WorldWideScience

Sample records for development surface modification

  1. Surface modification of polyester biomaterials for tissue engineering

    International Nuclear Information System (INIS)

    Jiao Yanpeng; Cui Fuzhai

    2007-01-01

    Surfaces play an important role in a biological system for most biological reactions occurring at surfaces and interfaces. The development of biomaterials for tissue engineering is to create perfect surfaces which can provoke specific cellular responses and direct new tissue regeneration. The improvement in biocompatibility of biomaterials for tissue engineering by directed surface modification is an important contribution to biomaterials development. Among many biomaterials used for tissue engineering, polyesters have been well documented for their excellent biodegradability, biocompatibility and nontoxicity. However, poor hydrophilicity and the lack of natural recognition sites on the surface of polyesters have greatly limited their further application in the tissue engineering field. Therefore, how to introduce functional groups or molecules to polyester surfaces, which ideally adjust cell/tissue biological functions, becomes more and more important. In this review, recent advances in polyester surface modification and their applications are reviewed. The development of new technologies or methods used to modify polyester surfaces for developing their biocompatibility is introduced. The results of polyester surface modifications by surface morphological modification, surface chemical group/charge modification, surface biomacromolecule modification and so on are reported in detail. Modified surface properties of polyesters directly related to in vitro/vivo biological performances are presented as well, such as protein adsorption, cell attachment and growth and tissue response. Lastly, the prospect of polyester surface modification is discussed, especially the current conception of biomimetic and molecular recognition. (topical review)

  2. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    Ion bombardment-induced modification of surfaces may be considered one of the significant scientific and technological developments of the last two decades. The understanding acquired concerning the underlying mechanisms of several phenomena occurring during ion-surface interactions has led to applications within different modern technologies. These include microelectronics, surface acoustical and optical technologies, solar energy conversion, thin film technology, ion implantation metallurgy, nuclear track technology, thermonuclear fusion, vacuum technology, cold welding technology, biomedicine (implantology). It has become clear that information on many relevant advances, regarding ion bombardment modification of surfaces is dispersed among journals involving fields sometimes not clearly related. This may result, in some cases, in a loss of the type of interdisciplinary exchange of ideas, which has proved to be so fruitful for the advancement of science and technology. This book has been planned in an attempt to collect at least some of today's relevant information about the experimental and theoretical knowledge related to surface modification and its application to technology. (Auth.)

  3. Surface Modification of Biomaterials: A Quest for Blood Compatibility

    Directory of Open Access Journals (Sweden)

    Achala de Mel

    2012-01-01

    Full Text Available Cardiovascular implants must resist thrombosis and intimal hyperplasia to maintain patency. These implants when in contact with blood face a challenge to oppose the natural coagulation process that becomes activated. Surface protein adsorption and their relevant 3D confirmation greatly determine the degree of blood compatibility. A great deal of research efforts are attributed towards realising such a surface, which comprise of a range of methods on surface modification. Surface modification methods can be broadly categorized as physicochemical modifications and biological modifications. These modifications aim to modulate platelet responses directly through modulation of thrombogenic proteins or by inducing antithrombogenic biomolecules that can be biofunctionalised onto surfaces or through inducing an active endothelium. Nanotechnology is recognising a great role in such surface modification of cardiovascular implants through biofunctionalisation of polymers and peptides in nanocomposites and through nanofabrication of polymers which will pave the way for finding a closer blood match through haemostasis when developing cardiovascular implants with a greater degree of patency.

  4. TEXTILE SURFACE MODIFICATION BY PYHSICAL VAPOR DEPOSITION – (REVIEW

    Directory of Open Access Journals (Sweden)

    YUCE Ismail

    2017-05-01

    Full Text Available Textile products are used in various branches of the industry from automotive to space products. Textiles produced for industrial use are generally referred to as technical textiles. Technical textiles are nowadays applied to several areas including transportation, medicine, agriculture, protection, sports, packaging, civil engineering and industry. There are rapid developments in the types of materials used in technical textiles. Therefore, modification and functionalization of textile surfaces is becoming more crucial. The improvements of the properties such as anti-bacterial properties, fire resistivity, UV radiation resistance, electrical conductivity, self cleaning, and super hydrophobic, is getting more concern with respect to developments in textile engineering. The properties of textile surfaces are closely related to the fiber structure, the differences in the polymer composition, the fiber mixture ratio, and the physical and chemical processes applied. Textile surface modifications can be examined in four groups under the name mechanical, chemical, burning and plasma. Surface modifications are made to improve the functionality of textile products. Textile surface modifications affect the properties of the products such as softness, adhesion and wettability. The purpose of this work is to reveal varieties of vapor deposition modifications to improve functionality. For this purpose, the pyhsical vapor deposition methods, their affects on textile products and their end-uses will be reviewed.

  5. The surface modification of polystyrene

    International Nuclear Information System (INIS)

    Tremlett, C.

    2000-03-01

    Polymers have ideal bulk properties for many applications. However, adhesion to many polymers is poor without surface pretreatment. This can result, for example, in peeling paint and printing, adhesive joint failure and bio-incompatibility. In applications such as painting, printing, adhesive bonding and biocompatibility, various cleaning or surface chemical modifications may be employed. A commodity polymer where pretreatment is sometimes needed is polystyrene. This project investigated, in detail, the effects of a novel method of modification namely mediated electrochemical oxidation (MEO), as a mode of surface modification on polystyrene and a comparison was made with other polymers. The resulting modification was investigated using a range of surface analysis techniques to obtain complementary information. These included, X-ray photoelectron spectroscopy, contact angles, static secondary ion mass spectrometry, atomic force microscopy, chemical derivatization, scanning electron microscopy, attenuated total reflection Fourier Transform infrared spectroscopy and composite lap shear joint testing. It has been shown that MEO modifies the surface of polystyrene introduced oxygen mainly as hydroxyl groups, and a small number of carbonyl groups, that are positioned only on the backbone hydrocarbon chain. This modification improved adhesion, was stable and samples could be stored in aqueous media. The resulting hydroxylation was further derivatized using an amino acid to provide a specialised surface. This was very different from the multiple oxygen functionalities introduced in the comparison studies by UV/ozone and plasma treatments. (author)

  6. Polymeric membranes: surface modification for minimizing (bio)colloidal fouling.

    Science.gov (United States)

    Kochkodan, Victor; Johnson, Daniel J; Hilal, Nidal

    2014-04-01

    This paper presents an overview on recent developments in surface modification of polymer membranes for reduction of their fouling with biocolloids and organic colloids in pressure driven membrane processes. First, colloidal interactions such as London-van der Waals, electrical, hydration, hydrophobic, steric forces and membrane surface properties such as hydrophilicity, charge and surface roughness, which affect membrane fouling, have been discussed and the main goals of the membrane surface modification for fouling reduction have been outlined. Thereafter the recent studies on reduction of (bio)colloidal of polymer membranes using ultraviolet/redox initiated surface grafting, physical coating/adsorption of a protective layer on the membrane surface, chemical reactions or surface modification of polymer membranes with nanoparticles as well as using of advanced atomic force microscopy to characterize (bio)colloidal fouling have been critically summarized. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. LASER SURFACE MODIFICATION OF TITANIUM ALLOYS — A REVIEW

    OpenAIRE

    Y. S. TIAN; C. Z. CHEN; D. Y. WANG; T. Q. LEI

    2005-01-01

    Recent developments of laser surface modification of titanium alloys for increasing their corrosion, wear and oxidation resistance are introduced. The effects of laser processing parameters on the resulting surface properties of titanium alloys are reviewed. The problems to be solved and the prospects in the field of laser modification of Ti alloys are discussed. Due to the intrinsic properties, a laser beam can be focused onto the metallic surface to produce a broad range of treatments depen...

  8. Energy conservation potential of surface modification technologies

    Energy Technology Data Exchange (ETDEWEB)

    Le, H.K.; Horne, D.M.; Silberglitt, R.S.

    1985-09-01

    This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

  9. Investigation of surface halide modification of nitrile butadiene rubber

    Science.gov (United States)

    Sukhareva, K. V.; Mikhailov, I. A.; Andriasyan, Yu O.; Mastalygina, E. E.; Popov, A. A.

    2017-12-01

    The investigation is devoted to the novel technology of surface halide modification of rubber samples based on nitrile butadiene rubber (NBR). 1,1,2-trifluoro-1,2,2-trichlorethane was used as halide modifier. The developed technology is characterized by production stages reduction to one by means of treating the rubber compound with a halide modifier. The surface halide modification of compounds based on nitrile butadiene rubber (NBR) was determined to result in increase of resistance to thermal oxidation and aggressive media. The conducted research revealed the influence of modification time on chemical resistance and physical-mechanical properties of rubbers under investigation.

  10. Surface Modification for Microreactor Fabrication

    Directory of Open Access Journals (Sweden)

    Wladyslaw Torbicz

    2006-04-01

    Full Text Available In this paper, methods of surface modification of different supports, i.e. glass andpolymeric beads for enzyme immobilisation are described. The developed method ofenzyme immobilisation is based on Schiff’s base formation between the amino groups onthe enzyme surface and the aldehyde groups on the chemically modified surface of thesupports. The surface of silicon modified by APTS and GOPS with immobilised enzymewas characterised by atomic force microscopy (AFM, time-of-flight secondary ion massspectroscopy (ToF-SIMS and infrared spectroscopy (FTIR. The supports withimmobilised enzyme (urease were also tested in combination with microreactors fabricatedin silicon and Perspex, operating in a flow-through system. For microreactors filled withurease immobilised on glass beads (Sigma and on polymeric beads (PAN, a very high andstable signal (pH change was obtained. The developed method of urease immobilisationcan be stated to be very effective.

  11. Development of Surface Modification Methods for Religaheart® Cardiac Support System

    Directory of Open Access Journals (Sweden)

    Major R.

    2016-09-01

    Full Text Available The work is a review of the methods of the surface modification performed by the authors dedicated for for cardiac support system. It presents the evolution of designing the surface dedicated to direct contact with blood. Initially thin and ultrathin coatings were developed. They were designed as a blood-polymer barrier. The pneumatic heart assist devices are made of a medical grade polyurethane. A major milestone was to create advanced ceramic thin films expressing the flexible effects deposited by physical techniques. Coatings have evolved. Another milestone was the surface reproducing the microenvironment to capture progenitor cells from the bloodstream. Thin coatings were prepared, using methods of ion been, controlled residual stresses were introduced. Wrinkles appeared without cracking. This enabled taking control over the process of cell differentiation. Alternatively, the tissue inspired structure resulted of the coating in the form of extracellular matrix. The outer surface was modified with synthetic materials. This enabled the effective proteins docking to induce cell growth, recreating the luminal side of the blood vessel. Coagulation processes have been slowed down. In addition, it was found pro-angiogenic effect.

  12. Surface modification of ceramics. Ceramics no hyomen kaishitsu

    Energy Technology Data Exchange (ETDEWEB)

    Hioki, T. (Toyota Central Research and Development Labs., Inc., Nagoya (Japan))

    1993-07-05

    Surface modification of ceramics and some study results using in implantation in surface modification are introduced. The mechanical properties (strength, fracture toughness, flaw resistance) of ceramics was improved and crack was repaired using surface modification by ion implantation. It is predicted that friction and wear properties are considerably affected because the hardness of ceramics is changed by ion implantation. Cementing and metalization are effective as methods for interface modification and the improvement of the adhesion power of the interface between metal and ceramic is their example. It was revealed that the improvement of mechanical properties of ceramics was achieved if appropriate surface modification was carried out. The market of ceramics mechanical parts is still small, therefore, the present situation is that the field of activities for surface modification of ceramics is also narrow. However, it is thought that in future, ceramics use may be promoted surely in the field like medicine and mechatronics. 8 refs., 4 figs.

  13. Microscale surface modifications for heat transfer enhancement.

    Science.gov (United States)

    Bostanci, Huseyin; Singh, Virendra; Kizito, John P; Rini, Daniel P; Seal, Sudipta; Chow, Louis C

    2013-10-09

    In this experimental study, two surface modification techniques were investigated for their effect on heat transfer enhancement. One of the methods employed the particle (grit) blasting to create microscale indentations, while the other used plasma spray coating to create microscale protrusions on Al 6061 (aluminum alloy 6061) samples. The test surfaces were characterized using scanning electron microscopy (SEM) and confocal scanning laser microscopy. Because of the surface modifications, the actual surface area was increased up to 2.8× compared to the projected base area, and the arithmetic mean roughness value (Ra) was determined to vary from 0.3 μm for the reference smooth surface to 19.5 μm for the modified surfaces. Selected samples with modified surfaces along with the reference smooth surface were then evaluated for their heat transfer performance in spray cooling tests. The cooling system had vapor-atomizing nozzles and used anhydrous ammonia as the coolant in order to achieve heat fluxes up to 500 W/cm(2) representing a thermal management setting for high power systems. Experimental results showed that the microscale surface modifications enhanced heat transfer coefficients up to 76% at 500 W/cm(2) compared to the smooth surface and demonstrated the benefits of these practical surface modification techniques to enhance two-phase heat transfer process.

  14. Development of bio/blood compatible polypropylene through low pressure nitrogen plasma surface modification

    International Nuclear Information System (INIS)

    Gomathi, N.; Rajasekar, R.; Babu, R. Rajesh; Mishra, Debasish; Neogi, S.

    2012-01-01

    Surface modification of polypropylene by nitrogen containing plasma was performed in this work in order to improve the wettability which resulted in enhanced biocompatibility and blood compatibility. Various nitrogen containing functional groups as well as oxygen containing functional groups were found to be incorporated to the polymer surface during plasma treatment and post plasma reaction respectively. Wettability of the polymers was evaluated by static contact angle measurement to show the improvement in hydrophilicity of plasma treated polypropylene. Cross linking and surface modification were reported to be dominating in the case of nitrogen plasma treatment compared to degradation. The effect of various process variables namely power, pressure, flow rate and treatment time on surface energy and weight loss was studied at various levels according to the central composite design of response surface methodology (RSM). Except pressure the other variables resulted in increased weight loss due to etching whereas with increasing pressure weight loss was found to increase and then decrease. The effect of process variables on surface morphology of polymers was evaluated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Well spread fibroblast cells on nitrogen plasma treated polypropylene due to the presence of CO, NH 2+ and NH + was observed. Reduced platelet adhesion and increased partial thromboplastin time evidenced the increased blood compatibility. - Highlights: ► Improved biocompatibility and blood compatibility of polypropylene. ► Nitrogen plasma surface modification. ► Maintaining a balance between polar group incorporation and weight loss due to etching. ► Optimization of process conditions by response surface methodology.

  15. Covalent Surface Modifications of Carbon Nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

    Pavia Sanders, Adriana [Sandia National Lab. (SNL-CA), Livermore, CA (United States); O' Bryan, Greg [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-07-01

    A report meant to document the chemistries investigated by the author for covalent surface modification of CNTs. Oxidation, cycloaddition, and radical reactions were explored to determine their success at covalently altering the CNT surface. Characterization through infrared spectroscopy, Raman spectroscopy, and thermo gravimetric analysis was performed in order to determine the success of the chemistries employed. This report is not exhaustive and was performed for CNT surface modification exploration as it pertains to the "Next Gen" project.

  16. Fabrication and surface-modification of implantable microprobes for neuroscience studies

    International Nuclear Information System (INIS)

    Cao, H; Nguyen, C M; Chiao, J C

    2012-01-01

    In this work implantable micro-probes for central nervous system (CNS) studies were developed on silicon and polyimide substrates. The probes which contained micro-electrode arrays with different surface modifications were designed for implantation in the CNS. The electrode surfaces were modified with nano-scale structures that could greatly increase the active surface area in order to enhance the electrochemical current outputs while maintaining micro-scale dimensions of the electrodes and probes. The electrodes were made of gold or platinum, and designed with different sizes. The silicon probes were modified by silicon nanowires fabricated with the vapor–liquid–solid mechanism at high temperatures. With polyimide substrates, the nanostructure modification was carried out by applying concentrated gold or silver colloid solutions onto the micro-electrodes at room temperature. The surfaces of electrodes before and after modification were observed by scanning electron microscopy. The silicon nanowire-modified surface was characterized by cyclic voltammetry. Experiments were carried out to investigate the improvement in sensing performance. The modified electrodes were tested with H 2 O 2 , electrochemical L-glutamate and dopamine. Comparisons between electrodes with and without nanostructure modification were conducted showing that the modifications have enhanced the signal outputs of the electrochemical neurotransmitter sensors

  17. Fabrication and surface-modification of implantable microprobes for neuroscience studies

    Science.gov (United States)

    Cao, H.; Nguyen, C. M.; Chiao, J. C.

    2012-06-01

    In this work implantable micro-probes for central nervous system (CNS) studies were developed on silicon and polyimide substrates. The probes which contained micro-electrode arrays with different surface modifications were designed for implantation in the CNS. The electrode surfaces were modified with nano-scale structures that could greatly increase the active surface area in order to enhance the electrochemical current outputs while maintaining micro-scale dimensions of the electrodes and probes. The electrodes were made of gold or platinum, and designed with different sizes. The silicon probes were modified by silicon nanowires fabricated with the vapor-liquid-solid mechanism at high temperatures. With polyimide substrates, the nanostructure modification was carried out by applying concentrated gold or silver colloid solutions onto the micro-electrodes at room temperature. The surfaces of electrodes before and after modification were observed by scanning electron microscopy. The silicon nanowire-modified surface was characterized by cyclic voltammetry. Experiments were carried out to investigate the improvement in sensing performance. The modified electrodes were tested with H2O2, electrochemical L-glutamate and dopamine. Comparisons between electrodes with and without nanostructure modification were conducted showing that the modifications have enhanced the signal outputs of the electrochemical neurotransmitter sensors.

  18. Corrosion principles and surface modification

    International Nuclear Information System (INIS)

    Kruger, J.

    1982-01-01

    This chapter examines the important strategies provided by the newer ideas of corrosion science and engineering that surface modification techniques must utilize to help prevent corrosion, especially the most damaging kind of aqueous corrosion, localized corrosion. Provides a brief introduction to the principles underlying the phenomenon of corrosion in order to use them to discuss surface modification strategies to combat corrosion. Discusses the electrochemistry of corrosion; the thermodynamics of corrosion; the kinetics of corrosion; thermodynamic strategies; and kinetic strategies (formation of more protective passive films; resistance to breakdown; ductility; repassivation)

  19. Research progress on laser surface modification of titanium alloys

    International Nuclear Information System (INIS)

    Tian, Y.S.; Chen, C.Z.; Li, S.T.; Huo, Q.H.

    2005-01-01

    Recent developments on laser surface modification of titanium and its alloys are reviewed. Due to the intrinsic properties of high coherence and directionality, laser beam can be focus onto metallic surface to perform a broad range of treatments such as remelting, alloying and cladding, which are used to improve the wear and corrosion resistance of titanium alloys. In addition, the fabrication of bioactive films on the surface of titanium alloys to improve their biocompatibility can be performed by the method of laser ablation deposition. The effect of some laser processing parameters on the resulting surface properties of titanium alloys is discussed. The problems to be solved and the prospects in the field of laser modification of titanium and its alloys are elucidated

  20. Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Han, Xiao [School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); Huang, Shiming [Department of Physics, Tongji University, Shanghai 200092 (China); Wang, Yilong, E-mail: yilongwang@tongji.edu.cn [Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); Shi, Donglu, E-mail: shid@ucmail.uc.edu [Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); The Materials Science and Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH 45221 (United States)

    2016-07-01

    Anisotropic yolk/shell or Janus inorganic/polystyrene nanocomposites were prepared by combining miniemulsion polymerization and sol–gel reaction. The morphologies of the anisotropic composites were found to be greatly influenced by surface modification of zinc oxide (ZnO) nanoparticle seeds. Two different types of the oleic acid modified ZnO nanoparticles (OA-ZnO) were prepared by post-treatment of commercial ZnO powder and homemade OA-ZnO nanoparticles. The morphologies and properties of the nanocomposites were investigated by transmission electron microscope (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDX). It was found that both post-treated OA-ZnO and in-situ prepared OA-ZnO nanoparticles resulted in the yolk–shell and Janus structure nanocomposites, but with varied size and morphology. These nanocomposites showed stable and strong fluorescence by introducing quantum dots as the co-seeds. The fluorescent anisotropic nanocomposites were decorated separately with surface carboxyl and hydroxyl groups. These composites with unique anisotropic properties will have high potential in biomedical applications, particularly in bio-detection. - Graphical abstract: Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles. - Highlights: • Non-magnetic anisotropic yolk/shell or Janus nanocomposites are prepared and characterized. • Different surface modification of zinc oxide (ZnO) nanoparticles results in varied morphology and size of the final product. • Fluorescent anisotropic nanocomposites embodying quantum dots are an ideal candidate for bio-detection applications.

  1. Surface Modification of Mg and Mg Alloys

    OpenAIRE

    Turhan, Can Metehan

    2012-01-01

    Progressively, the well explored and studied mechanical properties of a bulk metal are compared with the corrosion behaviour obtained from its surface, which enables promising improvements in desired applications. An example is magnesium metal: where, by developing new types of surface modifications by understanding its inconsistent corrosion behaviour, it would be possible to apply this engineering metal safely as a biocompatible metal, in addition to its widely used application areas such a...

  2. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    An historical overview of the main advances in the understanding of bombardment-induced surface topography is presented. The implantation and sputtering mechanisms which are relevant to ion bombardment modification of surfaces and consequent structural, electronic and compositional changes are described. Descriptions of plasma and ion-beam sputtering-induced film formation, primary ion-beam deposition, dual beam techniques, cluster of molecule ion-beam deposition, and modification of thin film properties by ion bombardment during deposition are presented. A detailed account is given of the analytical and computational modelling of topography from the viewpoint of first erosion theory. Finally, an account of the possible application and/or importance of textured surfaces in technologies and/or experimental techniques not considered in previous chapters is presented. refs.; figs.; tabs

  3. Tribological effects of polymer surface modification through plastic

    Indian Academy of Sciences (India)

    Tribological effects of polymer surface modification through plastic deformation. K O Low K J Wong ... In this regard, a surface modification technique through plastic deformation has been implemented. ... Bulletin of Materials Science | News.

  4. Organic light emitting diode with surface modification layer

    Science.gov (United States)

    Basil, John D.; Bhandari, Abhinav; Buhay, Harry; Arbab, Mehran; Marietti, Gary J.

    2017-09-12

    An organic light emitting diode (10) includes a substrate (12) having a first surface (14) and a second surface (16), a first electrode (32), and a second electrode (38). An emissive layer (36) is located between the first electrode (32) and the second electrode (38). The organic light emitting diode (10) further includes a surface modification layer (18). The surface modification layer (18) includes a non-planar surface (30, 52).

  5. Surface Modifications in Adhesion and Wetting

    Science.gov (United States)

    Longley, Jonathan

    Advances in surface modification are changing the world. Changing surface properties of bulk materials with nanometer scale coatings enables inventions ranging from the familiar non-stick frying pan to advanced composite aircraft. Nanometer or monolayer coatings used to modify a surface affect the macro-scale properties of a system; for example, composite adhesive joints between the fuselage and internal frame of Boeing's 787 Dreamliner play a vital role in the structural stability of the aircraft. This dissertation focuses on a collection of surface modification techniques that are used in the areas of adhesion and wetting. Adhesive joints are rapidly replacing the familiar bolt and rivet assemblies used by the aerospace and automotive industries. This transition is fueled by the incorporation of composite materials into aircraft and high performance road vehicles. Adhesive joints have several advantages over the traditional rivet, including, significant weight reduction and efficient stress transfer between bonded materials. As fuel costs continue to rise, the weight reduction is accelerating this transition. Traditional surface pretreatments designed to improve the adhesion of polymeric materials to metallic surfaces are extremely toxic. Replacement adhesive technologies must be compatible with the environment without sacrificing adhesive performance. Silane-coupling agents have emerged as ideal surface modifications for improving composite joint strength. As these coatings are generally applied as very thin layers (coatings using the buckling instability formed between two materials of a large elastic mismatch. The elastic modulus is found to effectively predict the joint strength of an epoxy/aluminum joint that has been reinforced with silane coupling agents. This buckling technique is extended to investigate the effects of chemical composition on the elastic modulus. Finally, the effect of macro-scale roughness on silane-reinforced joints is investigated

  6. Nanofibrillated Cellulose Surface Modification: A Review

    Directory of Open Access Journals (Sweden)

    Julien Bras

    2013-05-01

    Full Text Available Interest in nanofibrillated cellulose (NFC has increased notably over recent decades. This bio-based nanomaterial has been used essentially in bionanocomposites or in paper thanks to its high mechanical reinforcement ability or barrier property respectively. Its nano-scale dimensions and its capacity to form a strong entangled nanoporous network have encouraged the emergence of new high-value applications. It is worth noting that chemical surface modification of this material can be a key factor to achieve a better compatibility with matrices. In order to increase the compatibility in different matrices or to add new functions, surface chemical modification of NFC appears to be the prior choice to conserve its intrinsic nanofibre properties. In this review, the authors have proposed for the first time an overview of all chemical grafting strategies used to date on nanofibrillated cellulose with focus on surface modification such as physical adsorption, molecular grafting or polymer grafting.

  7. Modification of rubber surface by UV surface grafting

    International Nuclear Information System (INIS)

    Shanmugharaj, A.M.; Kim, Jin Kuk; Ryu, Sung Hun

    2006-01-01

    Rubber surface is subjected to ultraviolet radiation (UV) in the presence of allylamine and radiation sensitizer benzophenone (BP). Fourier transform infrared spectral studies reveal the presence of allylamine on the surface. The presence of irregular needle shapes on the surface as observed in scanning electron micrographs also confirms the polymerized allylamine on the surface. Allylamine coatings have been further confirmed from atomic force microscopy (AFM) analysis. Thermogravimetric analysis (TGA) reveals that allylamine coating on the rubber surface lowers the thermal degradation rate. The contact angle between the water and rubber surface decreases for the modified rubber surface confirming the surface modification due to UV surface grafting

  8. The process development of laser surface modification of commercially pure titanium (Grade 2) with rhenium

    Science.gov (United States)

    Kobiela, K.; Smolina, I.; Dziedzic, R.; Szymczyk, P.; Kurzynowski, T.; Chlebus, E.

    2016-12-01

    The paper presents the results of the process development of laser surface modification of commercially pure titanium with rhenium. The criterion of the successful/optimal process is the repetitive geometry of the surface, characterized by predictable and repetitive chemical composition over its entire surface as well as special mechanical properties (hardness and wear resistance). The analysis of surface geometry concluded measurements of laser penetration depth and heat affected zone (HAZ), the width of a single track as well as width of a clad. The diode laser installed on the industrial robot carried out the laser treatment. This solution made possible the continuous supply of powder to the substrate during the process. The aim of an investigation is find out the possibility of improving the tribological characteristics of the surface due to the rhenium alloying. The verification of the surface properties (tribological) concluded geometry measurements, microstructure observation, hardness tests and evaluation of wear resistance.

  9. Modification of surfaces and surface layers by non equilibrium processes

    International Nuclear Information System (INIS)

    Beamson, G.; Brennan, W.J.; Clark, D.T.; Howard, J.

    1988-01-01

    Plasmas are examples of non-equilibrium phenomena which are being used increasingly for the synthesis and modification of materials impossible by conventional routes. This paper introduces methods available by describing the construction and characteristics of some equipment used for the production of different types of plasmas and other non-equilibrium phenomena. This includes high energy ion beams. The special features, advantages and disadvantages of the techniques will be described. There are a multitude of potential application relevant to electronic, metallic, ceramic, and polymeric materials. However, scale-up from the laboratory to production equipment depends on establishing a better understanding of both the physics and chemistry of plasma as well as plasma-solid interactions. Examples are given of how such an understanding can be gained. The chemical analysis of polymer surfaces undergoing modification by inert gas, hydrogen or oxygen plasmas is shown to give physical information regarding the relative roles of diffusion of active species, and direct and radiative energy transfer from the plasma. Surface modification by plasma depositing a new material onto an existing substrate is discussed with particular reference to the deposition of amorphous carbon films. Applications of the unique properties of these films are outlined together with our current understanding of these properties based on chemical and physical methods of analysis of both the films and the plasmas producing them. Finally, surface modification by ion beams is briefly illustrated using examples from the electronics and metals industries where the modification has had a largely physical rather than chemical effect on the starting material. (orig.)

  10. Corrosion and surface modification on biocompatible metals: A review.

    Science.gov (United States)

    Asri, R I M; Harun, W S W; Samykano, M; Lah, N A C; Ghani, S A C; Tarlochan, F; Raza, M R

    2017-08-01

    Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Laser modification of macroscopic properties of metal surface layer

    Science.gov (United States)

    Kostrubiec, Franciszek

    1995-03-01

    Surface laser treatment of metals comprises a number of diversified technological operations out of which the following can be considered the most common: oxidation and rendering surfaces amorphous, surface hardening of steel, modification of selected physical properties of metal surface layers. In the paper basic results of laser treatment of a group of metals used as base materials for electric contacts have been presented. The aim of the study was to test the usability of laser treatment from the viewpoint of requirements imposed on materials for electric contacts. The results presented in the paper refer to two different surface treatment technologies: (1) modification of infusible metal surface layer: tungsten and molybdenum through laser fusing of their surface layer and its crystallization, and (2) modification of surface layer properties of other metals through laser doping of their surface layer with foreign elements. In the paper a number of results of experimental investigations obtained by the team under the author's supervision are presented.

  12. Surface Modification of Biomaterials: A Quest for Blood Compatibility

    OpenAIRE

    de Mel, Achala; Cousins, Brian G.; Seifalian, Alexander M.

    2012-01-01

    Cardiovascular implants must resist thrombosis and intimal hyperplasia to maintain patency. These implants when in contact with blood face a challenge to oppose the natural coagulation process that becomes activated. Surface protein adsorption and their relevant 3D confirmation greatly determine the degree of blood compatibility. A great deal of research efforts are attributed towards realising such a surface, which comprise of a range of methods on surface modification. Surface modification ...

  13. Plasma assisted surface coating/modification processes: An emerging technology

    Science.gov (United States)

    Spalvins, T.

    1986-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation). These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  14. Plasma assisted surface coating/modification processes - An emerging technology

    Science.gov (United States)

    Spalvins, T.

    1987-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation. These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  15. Excimer laser surface modification: Process and properties

    Energy Technology Data Exchange (ETDEWEB)

    Jervis, T.R.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hirvonen, J.P. [Technical Research Institute, Espoo (Finland). Metallurgy Lab.

    1992-12-01

    Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials.

  16. Stability studies of plasma modification effects of polylactide and polycaprolactone surface layers

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Stepczyńska, Magdalena [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, Marii Skłodowskiej-Curie 55, 87‐100 Toruń (Poland); Rytlewski, Piotr; Jagodziński, Bartłomiej; Żenkiewicz, Marian [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland)

    2016-07-30

    Highlights: • Plasma modification affects surface roughness, wettability and surface energy. • Polylactide and polycaprolactone aging causes decay of the modification effects. • Changes in the surface characteristic and wettability deterioration were observed. • The decay occurs due to migration of low molecular weight molecules to the surface. • Plasma modification effect lasts longer in the case of polycaprolactone. - Abstract: The article presents results of research on the stability of oxygen plasma modification effects of polylactide and polycaprolactone surface layers. The modified samples were aged for three, six or nine weeks. The studies were carried out using scanning electron microscopy, goniometry and Fourier transform infrared spectroscopy. Studies have shown that the plasma modification has significant impact on the geometric structure and chemical composition of the surface, wettability and surface energy of tested polymers. The modification effects are not permanent. It has been observed that over time the effects of plasma modification fade. Studies have shown that modifying effect lasts longer in the case of polycaprolactone.

  17. Plasma-Assisted Synthesis and Surface Modification of Electrode Materials for Renewable Energy.

    Science.gov (United States)

    Dou, Shuo; Tao, Li; Wang, Ruilun; El Hankari, Samir; Chen, Ru; Wang, Shuangyin

    2018-02-14

    Renewable energy technology has been considered as a "MUST" option to lower the use of fossil fuels for industry and daily life. Designing critical and sophisticated materials is of great importance in order to realize high-performance energy technology. Typically, efficient synthesis and soft surface modification of nanomaterials are important for energy technology. Therefore, there are increasing demands on the rational design of efficient electrocatalysts or electrode materials, which are the key for scalable and practical electrochemical energy devices. Nevertheless, the development of versatile and cheap strategies is one of the main challenges to achieve the aforementioned goals. Accordingly, plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices. Here, the recent progress on the development of nonthermal plasma technology is highlighted for the synthesis and surface modification of advanced electrode materials for renewable energy technology including electrocatalysts for fuel cells, water splitting, metal-air batteries, and electrode materials for batteries and supercapacitors, etc. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Surface modification of zinc oxide nanorods for potential applications in organic materials

    International Nuclear Information System (INIS)

    Zhang Lei; Zhong Min; Ge Hongliang

    2011-01-01

    A facile and simple modification method towards changing surface property of ZnO nanorods from a hydrophilic one to a hydrophobic one have been developed by refluxing precursor in three-necked flask. Comparing with the other modifiers discussed in the paper, NDZ-311w titanate coupling agent was selected as the best one not only because of the good lipophilic modification effect, but also for its multifunctional groups could play a crucial part in further composite with organic materials. Moreover, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively, were used to evaluate the morphology, structure and combinative way before and after surface modification. The TEM result showed, after modifying process, there was a thin layer capping on the surface of ZnO nanorods which could be considered as NDZ-311w titanate coupling agent. Through the structure analysis by XRD, it was found that the surface modification had not substantially altered crystalline structure. Besides, the FT-IR test proved that NDZ-311w titanate coupling agent was rather covalently bonded to the surface of ZnO nanorods than physically capping. More practically speaking, the NDZ-311w titanate coupling agent modified ZnO nanorods have much more potential applications in organic materials than unmodified ones.

  19. Laser surface modification of PEEK

    Energy Technology Data Exchange (ETDEWEB)

    Riveiro, A., E-mail: ariveiro@uvigo.es [Applied Physics Department, University of Vigo ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Centro Universitario de la Defensa, Escuela Naval Militar, Plaza de Espana 2, 36920 Marin (Spain); Soto, R.; Comesana, R.; Boutinguiza, M.; Val, J. del; Quintero, F.; Lusquinos, F.; Pou, J. [Applied Physics Department, University of Vigo ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Role of laser irradiation wavelength on the surface modification of PEEK (polyether-ether-ketone) was investigated. Black-Right-Pointing-Pointer Adequate processing conditions to improve wettability, roughness, and cell adhesion characteristics are determined. Black-Right-Pointing-Pointer A design of experiments (DOE) methodology was performed. Black-Right-Pointing-Pointer UV (355 nm) radiation is the most promising laser radiation for improving the adhesive surface properties of PEEK. - Abstract: Polyether-ether-ketone (PEEK) is a synthetic thermoplastic polymer with excellent mechanical and chemical properties, which make it attractive for the field of reconstructive surgery. Nevertheless, this material has a poor interfacial biocompatibility due to its large chemical stability which induces poor adhesive bonding properties. The possibilities of enhancing the PEEK adhesive properties by laser treatments have been explored in the past. This paper presents a systematic approach to discern the role of laser irradiation wavelength on the surface modification of PEEK under three laser wavelengths ({lambda} = 1064, 532, and 355 nm) with the aim to determine the most adequate processing conditions to increase the roughness and wettability, the main parameters affecting cell adhesion characteristics of implants. Overall results show that the ultraviolet ({lambda} = 355 nm) laser radiation is the most suitable one to enhance surface wettability of PEEK.

  20. Designing Pulse Laser Surface Modification of H13 Steel Using Response Surface Method

    Science.gov (United States)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2011-01-01

    This paper presents a design of experiment (DOE) for laser surface modification process of AISI H13 tool steel in achieving the maximum hardness and minimum surface roughness at a range of modified layer depth. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). The response surface method with Box-Behnken design approach in Design Expert 7 software was used to design the H13 laser surface modification process. Metallographic study and image analysis were done to measure the modified layer depth. The modified surface roughness was measured using two-dimensional surface profilometer. The correlation of the three laser processing parameters and the modified surface properties was specified by plotting three-dimensional graph. The hardness properties were tested at 981 mN force. From metallographic study, the laser modified surface depth was between 37 μm and 150 μm. The average surface roughness recorded from the 2D profilometry was at a minimum value of 1.8 μm. The maximum hardness achieved was between 728 and 905 HV0.1. These findings are significant to modern development of hard coatings for wear resistant applications.

  1. Development of Surface Modification Techniques for Enhanced Safety of Light Water Reactors: Recent Progress and Future Direction at THLAB

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Gwang Hyeok; Jeong, Ui Ju; Son, Hong Hyun; Jeun, Gyoo Dong; Kim, Sung Joong [Hanyang University, Daejeon (Korea, Republic of)

    2016-05-15

    They concluded that the CHF enhancement in nanofluid boiling was mainly affected by the surface characteristics of the developed layer. Furthermore, an introduction of surface modification can be utilized to secure the safety of nuclear reactor systems. At many components of the reactor systems, energetic boiling heat transfer occurs, and potential thermal attack to the systems is expected under normal or accident environments. In particular, during a reactor operation, fission energy is deposited in the fuel assemblies in a core. Also, under severe conditions, failure of a reactor vessel may occur by high temperature molten materials. In this article, we introduce the surface modification techniques and recent achievements. After a brief description of each deposition mechanism, an assessment of thermal margin for both the technologies is discussed based on pool boiling experiments conducted at THLAB. Moreover, in the latter part of each chapter, experimental facilities for applied heat transfer tests to consider reactor environments are presented.

  2. Development of Fabrication Methods of Filler/Polymer Nanocomposites: With Focus on Simple Melt-Compounding-Based Approach without Surface Modification of Nanofillers

    Science.gov (United States)

    Tanahashi, Mitsuru

    2010-01-01

    Many attempts have been made to fabricate various types of inorganic nanoparticle-filled polymers (filler/polymer nanocomposites) by a mechanical or chemical approach. However, these approaches require modification of the nanofiller surfaces and/or complicated polymerization reactions, making them unsuitable for industrial-scale production of the nanocomposites. The author and coworkers have proposed a simple melt-compounding method for the fabrication of silica/polymer nanocomposites, wherein silica nanoparticles without surface modification were dispersed through the breakdown of loose agglomerates of colloidal nano-silica spheres in a kneaded polymer melt. This review aims to discuss experimental techniques of the proposed method and its advantages over other developed methods.

  3. Development of Fabrication Methods of Filler/Polymer Nanocomposites: With Focus on Simple Melt-Compounding-Based Approach without Surface Modification of Nanofillers

    Directory of Open Access Journals (Sweden)

    Mitsuru Tanahashi

    2010-03-01

    Full Text Available Many attempts have been made to fabricate various types of inorganic nanoparticle-filled polymers (filler/polymer nanocomposites by a mechanical or chemical approach. However, these approaches require modification of the nanofiller surfaces and/or complicated polymerization reactions, making them unsuitable for industrial-scale production of the nanocomposites. The author and coworkers have proposed a simple melt-compounding method for the fabrication of silica/polymer nanocomposites, wherein silica nanoparticles without surface modification were dispersed through the breakdown of loose agglomerates of colloidal nano-silica spheres in a kneaded polymer melt. This review aims to discuss experimental techniques of the proposed method and its advantages over other developed methods.

  4. Covalent and stable CuAAC modification of silicon surfaces for control of cell adhesion

    DEFF Research Database (Denmark)

    Vutti, Surendra; Buch-Månson, Nina; Schoffelen, Sanne

    2015-01-01

    in the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging. We demonstrate that the vapor-phase functionalization only provided transient surface modification that was lost...... on extensive washing. For stable surface modification, a liquid-phase method was developed. In this method, silicon wafers were decorated with azides, either by silanization with (3-azidopropyl)triethoxysilane or by conversion of the amine groups of an aminopropylated surface by means of the azido...

  5. Surface modifications of magnesium alloys for biomedical applications.

    Science.gov (United States)

    Yang, Jingxin; Cui, Fuzhai; Lee, In Seop

    2011-07-01

    In recent years, research on magnesium (Mg) alloys had increased significantly for hard tissue replacement and stent application due to their outstanding advantages. Firstly, Mg alloys have mechanical properties similar to bone which avoid stress shielding. Secondly, they are biocompatible essential to the human metabolism as a factor for many enzymes. In addition, main degradation product Mg is an essential trace element for human enzymes. The most important reason is they are perfectly biodegradable in the body fluid. However, extremely high degradation rate, resulting in too rapid loss of mechanical strength in chloride containing environments limits their applications. Engineered artificial biomaterials with appropriate mechanical properties, surface chemistry, and surface topography are in a great demand. As the interaction between the cells and tissues with biomaterials at the tissue--implant interface is a surface phenomenon; surface properties play a major role in determining both the biological response to implants and the material response to the physiological condition. Therefore, the ability to modify the surface properties while preserve the bulk properties is important, and surface modification to form a hard, biocompatible and corrosion resistant modified layer have always been an interesting topic in biomaterials field. In this article, attempts are made to give an overview of the current research and development status of surface modification technologies of Mg alloys for biomedical materials research. Further, the advantages/disadvantages of the different methods and with regard to the most promising method for Mg alloys are discussed. Finally, the scientific challenges are proposed based on own research and the work of other scientists.

  6. Advancing Sustainable Catalysis with Magnetite Surface Modification and Synthetic Applications

    Science.gov (United States)

    This article surveys the recent developments in the synthesis, surface modification, and synthetic applications of magnetitenanoparticles. The emergence of iron(II,III) oxide (triiron tetraoxide or magnetite; Fe3O4, or FeO•Fe2O3) nanoparticles as a sustainable support in heteroge...

  7. Surface-enhanced Raman spectroscopy competitive binding biosensor development utilizing surface modification of silver nanocubes and a citrulline aptamer

    Science.gov (United States)

    Walton, Brian M.; Jackson, George W.; Deutz, Nicolaas; Cote, Gerard

    2017-07-01

    A point-of-care (PoC) device with the ability to detect biomarkers at low concentrations in bodily fluids would have an enormous potential for medical diagnostics outside the central laboratory. One method to monitor analytes at low concentrations is by using surface-enhanced Raman spectroscopy (SERS). In this preliminary study toward using SERS for PoC biosensing, the surface of colloidal silver (Ag) nanocubes has been modified to test the feasibility of a competitive binding SERS assay utilizing aptamers against citrulline. Specifically, Ag nanocubes were functionalized with mercaptobenzoic acid, as well as a heterobifunctional polyethylene glycol linker that forms an amide bond with the amino acid citrulline. After the functionalization, the nanocubes were characterized by zeta-potential, transmission electron microscopy images, ultraviolet/visible spectroscopy, and by SERS. The citrulline aptamers were developed and tested using backscattering interferometry. The data show that our surface modification method does work and that the functionalized nanoparticles can be detected using SERS down to a 24.5 picomolar level. Last, we used microscale thermophoresis to show that the aptamers bind to citrulline with at least a 50 times stronger affinity than other amino acids.

  8. Development of a High Efficiency Dry Powder Inhaler: Effects of Capsule Chamber Design and Inhaler Surface Modifications

    Science.gov (United States)

    Behara, Srinivas R.B.; Farkas, Dale R.; Hindle, Michael; Longest, P. Worth

    2013-01-01

    Purpose The objective of this study was to explore the performance of a high efficiency dry powder inhaler (DPI) intended for excipient enhanced growth (EEG) aerosol delivery based on changes to the capsule orientation and surface modifications of the capsule and device. Methods DPIs were constructed by combining newly designed capsule chambers (CC) with a previously developed three-dimensional (3D) rod array for particle deagglomeration and a previously optimized EEG formulation. The new CCs oriented the capsule perpendicular to the incoming airflow and were analyzed for different air inlets at a constant pressure drop across the device. Modifications to the inhaler and capsule surfaces included use of metal dispersion rods and surface coatings. Aerosolization performance of the new DPIs was evaluated and compared with commercial devices. Results The proposed capsule orientation and motion pattern increased capsule vibrational frequency and reduced the aerosol MMAD compared with commercial/modified DPIs. The use of metal rods in the 3D array further improved inhaler performance. Coating the inhaler and capsule with PTFE significantly increased emitted dose (ED) from the optimized DPI. Conclusions High efficiency performance is achieved for EEG delivery with the optimized DPI device and formulation combination producing an aerosol with MMAD 90%, and ED > 80%. PMID:23949304

  9. Development of a high efficiency dry powder inhaler: effects of capsule chamber design and inhaler surface modifications.

    Science.gov (United States)

    Behara, Srinivas R B; Farkas, Dale R; Hindle, Michael; Longest, P Worth

    2014-02-01

    The objective of this study was to explore the performance of a high efficiency dry powder inhaler (DPI) intended for excipient enhanced growth (EEG) aerosol delivery based on changes to the capsule orientation and surface modifications of the capsule and device. DPIs were constructed by combining newly designed capsule chambers (CC) with a previously developed three-dimensional (3D) rod array for particle deagglomeration and a previously optimized EEG formulation. The new CCs oriented the capsule perpendicular to the incoming airflow and were analyzed for different air inlets at a constant pressure drop across the device. Modifications to the inhaler and capsule surfaces included use of metal dispersion rods and surface coatings. Aerosolization performance of the new DPIs was evaluated and compared with commercial devices. The proposed capsule orientation and motion pattern increased capsule vibrational frequency and reduced the aerosol MMAD compared with commercial/modified DPIs. The use of metal rods in the 3D array further improved inhaler performance. Coating the inhaler and capsule with PTFE significantly increased emitted dose (ED) from the optimized DPI. High efficiency performance is achieved for EEG delivery with the optimized DPI device and formulation combination producing an aerosol with MMAD  90%, and ED > 80%.

  10. Surface morphological modification of crosslinked hydrophilic co-polymers by nanosecond pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Primo, Gastón A.; Alvarez Igarzabal, Cecilia I. [IMBIV (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba X5000HUA (Argentina); Pino, Gustavo A.; Ferrero, Juan C. [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina); Rossa, Maximiliano, E-mail: mrossa@fcq.unc.edu.ar [INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, and Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Córdoba X5000IUS (Argentina)

    2016-04-30

    Graphical abstract: - Highlights: • Laser-induced surface modification of crosslinked hydrophilic co-polymers by ns pulses. • Formation of ablation craters observed under most of the single-pulse experimental conditions. • UV laser foaming of dried hydrogel samples resulting from single- and multiple-pulse experiments. • Threshold values of the incident laser fluence reported for the observed surface modifications. • Lower threshold fluences for acrylate-based, compared to acrylamide-based hydrogels. - Abstract: This work reports an investigation of the surface modifications induced by irradiation with nanosecond laser pulses of ultraviolet and visible wavelengths on crosslinked hydrophilic co-polymeric materials, which have been functionalized with 1-vinylimidazole as a co-monomer. A comparison is made between hydrogels differing in the base co-monomer (N,N-dimethylaminoethyl methacrylate and N-[3-(dimethylamino)propyl] methacrylamide) and in hydration state (both swollen and dried states). Formation of craters is the dominant morphological change observed by ablation in the visible at 532 nm, whereas additional, less aggressive surface modifications, chiefly microfoams and roughness, are developed in the ultraviolet at 266 nm. At both irradiation wavelengths, threshold values of the incident laser fluence for the observation of the various surface modifications are determined under single-pulse laser irradiation conditions. It is shown that multiple-pulse irradiation at 266 nm with a limited number of laser shots can be used alternatively for generating a regular microfoam layer at the surface of dried hydrogels based on N,N-dimethylaminoethyl methacrylate. The observations are rationalized on the basis of currently accepted mechanisms for laser-induced polymer surface modification, with a significant contribution of the laser foaming mechanism. Prospective applications of the laser-foamed hydrogel matrices in biomolecule immobilization are suggested.

  11. MODIFICATION OF SURFACE KONDENSITSIONNYH AEROSOLS WELDING AND METALLURGICHESKIH PRODUCTIONS

    Directory of Open Access Journals (Sweden)

    A. A. Ennan

    2016-04-01

    Full Text Available Chemical modification of surface kondensitsionnyh aerosols (KA which formation when heat treatment metals (process of weld, foundry processes with application chlorosilanes are suggested. Adsorbtion vapor of water on modification powders KA decreases and changes in varies from modifier and conditions modification are setted.

  12. Comparison of several innovative bridge cable surface modifications

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos T.

    Over the last two decades, several bridge cable manufacturers have introduced surface modifications on the high-density polyethylene (HDPE) sheathing that is installed for the protection of inner cable strands or wires. The modifications are based on research undertaken predominantly in Europe...

  13. Induction of surface modification of polytetrafluoroethylene with proton ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Noh, I S; Kim, H R; Choi, Y J; Park, H S [Seoul National Univ. of Technology, Seoul (Korea, Republic of)

    2007-04-15

    Cardiovascular disease is one of the leading causes of the death in the USA and developed countries. More than 570,000 artery bypass graft surgeries per USA are performed each year, though percutaneous devices have abounded in extreme cases. Based on the surgery follow-ups, large diameter expanded polytetrafluoroethylene (ePTFE) (>5 mm) are clinically employed with good results but its clinical applications in smaller vessels is still problematic due to thrombosis and neointima formation. Achievement of high patency grafts has been to some extent achieved by numerous methods of surface modification techniques, but its results are less than its initial hopes. As examples, endothelial cells coated on the luminal surface of ePTFE has demonstrated limited success after recirculation. Surface modifications of PTFE film with either argon ion beam or UV light from Xe-excimer lamp were reported to increase its interaction with vascular endothelial cell. Surface modification of poly(lactide-co-glycolide)[PLGA] is also very important in tissue engineering, in where induction of its initial high cellular adhesion and spreading is a critical step for development of tissue engineering medical products. We previously reported tissue engineering of the hybrid ePTFE scaffold by seeding smooth muscle cells and subsequently evaluation of its tissue regeneration behaviors and stabilities with circulation of pulsatile flow. To improve its tissue engineering more quickly, we here performed surface modification of ePTFE and porous PLGA scaffold and evaluated its subsequent chemical and biological properties after treating its surface with low energy ion beams. The porous ePTFE was prepared in a round shape (diameter = 1 cm) and dried after organic solvent extraction for ion beam treatment. Another porous PLGA layers (d = 1 cm, t = 1 cm with approximately 92% porosity) were fabricated and treated its surface by irradiating low energy either nitrogen or argon ion beams (1 keV, 1x1015 ions

  14. Induction of surface modification of polytetrafluoroethylene with proton ion beams

    International Nuclear Information System (INIS)

    Noh, I. S.; Kim, H. R.; Choi, Y. J.; Park, H. S.

    2007-04-01

    Cardiovascular disease is one of the leading causes of the death in the USA and developed countries. More than 570,000 artery bypass graft surgeries per USA are performed each year, though percutaneous devices have abounded in extreme cases. Based on the surgery follow-ups, large diameter expanded polytetrafluoroethylene (ePTFE) (>5 mm) are clinically employed with good results but its clinical applications in smaller vessels is still problematic due to thrombosis and neointima formation. Achievement of high patency grafts has been to some extent achieved by numerous methods of surface modification techniques, but its results are less than its initial hopes. As examples, endothelial cells coated on the luminal surface of ePTFE has demonstrated limited success after recirculation. Surface modifications of PTFE film with either argon ion beam or UV light from Xe-excimer lamp were reported to increase its interaction with vascular endothelial cell. Surface modification of poly(lactide-co-glycolide)[PLGA] is also very important in tissue engineering, in where induction of its initial high cellular adhesion and spreading is a critical step for development of tissue engineering medical products. We previously reported tissue engineering of the hybrid ePTFE scaffold by seeding smooth muscle cells and subsequently evaluation of its tissue regeneration behaviors and stabilities with circulation of pulsatile flow. To improve its tissue engineering more quickly, we here performed surface modification of ePTFE and porous PLGA scaffold and evaluated its subsequent chemical and biological properties after treating its surface with low energy ion beams. The porous ePTFE was prepared in a round shape (diameter = 1 cm) and dried after organic solvent extraction for ion beam treatment. Another porous PLGA layers (d = 1 cm, t = 1 cm with approximately 92% porosity) were fabricated and treated its surface by irradiating low energy either nitrogen or argon ion beams (1 keV, 1x1015 ions

  15. Effects of aluminium surface morphology and chemical modification on wettability

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, M., E-mail: mar@sbi.aau.dk [Department of Energy and Environment, Danish Building Research Institute, Aalborg University, A.C. Meyers Vænge 15, 2450 København SV (Denmark); Fojan, P.; Gurevich, L. [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4, DK-9220 Aalborg East (Denmark); Afshari, A. [Department of Energy and Environment, Danish Building Research Institute, Aalborg University, A.C. Meyers Vænge 15, 2450 København SV (Denmark)

    2014-03-01

    Highlights: • Successful surface modification procedures on aluminium samples were performed involving formation of the layer of hydrophilic hyperbranched polyethyleneglycol (PEG) via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. • The groups of surfaces with hydrophobic behavior were found to follow the Wenzel model. • A transition from Cassie–Baxter's to Wenzel's regime was observed due to changing of the surface roughness upon mechanical polishing in aluminium samples. - Abstract: Aluminium alloys are some of the predominant metals in industrial applications such as production of heat exchangers, heat pumps. They have high heat conductivity coupled with a low specific weight. In cold working conditions, there is a risk of frost formation on the surface of aluminium in the presence of water vapour, which can lead to the deterioration of equipment performance. This work addresses the methods of surface modification of aluminium and their effect of the underlying surface morphology and wettability, which are the important parameters for frost formation. Three groups of real-life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types of surface modifications the contact angle of water droplets on aluminium samples can be varied from 12° to more than 120°. A crossover from Cassie–Baxter to Wenzel regime upon changing the surface

  16. Vacuum-based surface modification of organic and metallic substrates

    Science.gov (United States)

    Torres, Jessica

    Surface physico-chemical properties play an important role in the development and performance of materials in different applications. Consequently, understanding the chemical and physical processes involved during surface modification strategies is of great scientific and technological importance. This dissertation presents results from the surface modification of polymers, organic films and metallic substrates with reactive species, with the intent of simulating important modification processes and elucidating surface property changes of materials under different environments. The reactions of thermally evaporated copper and titanium with halogenated polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) are used to contrast the interaction of metals with polymers. Results indicate that reactive metallization is thermodynamically favored when the metal-halogen bond strength is greater than the carbon-halogen bond strength. X-ray post-metallization treatment results in an increase in metal-halide bond formation due to the production of volatile halogen species in the polymer that react with the metallic overlayer. The reactions of atomic oxygen (AO) and atomic chlorine with polyethylene (PE) and self-assembled monolayers (SAMs) films were followed to ascertain the role of radical species during plasma-induced polymer surface modification. The reactions of AO with X-ray modified SAMs are initially the dominated by the incorporation of new oxygen containing functionality at the vacuum/film interface, leading to the production of volatile carbon containing species such as CO2 that erodes the hydrocarbon film. The reaction of atomic chlorine species with hydrocarbon SAMs, reveals that chlorination introduces C-Cl and C-Cl2 functionalities without erosion. A comparison of the reactions of AO and atomic chlorine with PE reveal a maximum incorporation of the corresponding C-O and C-Cl functionalities at the polymer surface. A novel method to prepare phosphorous

  17. Wind-Tunnel Investigation of the Aerodynamic Performance of Surface-Modification Cables

    Directory of Open Access Journals (Sweden)

    Hiroshi Katsuchi

    2017-12-01

    Full Text Available The wind-induced vibration of stay cables of cable-stayed bridges, which includes rain-wind-induced vibration (RWIV and dry galloping (DG, has been studied for a considerable amount of time. In general, mechanical dampers or surface modification are applied to suppress the vibration. In particular, several types of surface-modification cable, including indentation, longitudinally parallel protuberance, helical fillet, and U-shaped grooving, have been developed. Recently, a new type of aerodynamically stable cable with spiral protuberances was developed. It was confirmed that the cable has a low drag force coefficient, like an indented cable, and that it prevented the formation of water rivulets on the cable surface. In this study, the stability for RWIV of this cable was investigated with various flow angles and protuberance dimensions in a wind-tunnel test. It was found that the spiral protuberance cable is aerodynamically stable against both RWIV and DG for all test wind angles. The effects of the protuberance dimensions were also clarified. Keywords: Rain-wind-induced vibration, Dry galloping, Stay cable, Wind-tunnel test

  18. Towards convective heat transfer enhancement: surface modification, characterization and measurement techniques

    NARCIS (Netherlands)

    Taha, T.J.; Thakur, D.B.; van der Meer, Theodorus H.

    2012-01-01

    In this work, heat transfer surface modification and heat transfer measurement technique is developed. Heat transfer investigation was aimed to study the effect of carbon nano fibers (extremely high thermal conductive material) on the enhancement level in heat transfer. Synthesis of these carbon

  19. Modification of Material Surface Using Plasma-Enhanced Ion Beams

    National Research Council Canada - National Science Library

    Bystritskii, V

    1998-01-01

    ...) Technology for Materials Surface Modification. Following second year programmatic plan, formulated in the conclusion of the 1-st year report we focused our effort on study of aluminum alloys modification (Al2024, 6061, 7075...

  20. Surface modification effects on defect-related photoluminescence in colloidal CdS quantum dots.

    Science.gov (United States)

    Lee, TaeGi; Shimura, Kunio; Kim, DaeGwi

    2018-05-03

    We investigated the effects of surface modification on the defect-related photoluminescence (PL) band in colloidal CdS quantum dots (QDs). A size-selective photoetching process and a surface modification technique with a Cd(OH)2 layer enabled the preparation of size-controlled CdS QDs with high PL efficiency. The Stokes shift of the defect-related PL band before and after the surface modification was ∼1.0 eV and ∼0.63 eV, respectively. This difference in the Stokes shifts suggests that the origin of the defect-related PL band was changed by the surface modification. Analysis by X-ray photoelectron spectroscopy revealed that the surface of the CdS QDs before and after the surface modification was S rich and Cd rich, respectively. These results suggest that Cd-vacancy acceptors and S-vacancy donors affect PL processes in CdS QDs before and after the surface modification, respectively.

  1. Surface Modification Of Implants For Bone Surgery

    Directory of Open Access Journals (Sweden)

    Marciniak J.

    2015-09-01

    Full Text Available The study discusses the methods of surface modification methods for AISAI 316 L steel and Ti6Al4V ELI titanium alloy, dedicated to complex design implants used in bone surgery. Results of structural tests have been presented along with those evaluating the physicochemical properties of the formed surface layers. Clinical feasibility of the surface layers has also been evaluated.

  2. Surface modification of protein enhances encapsulation in chitosan nanoparticles

    Science.gov (United States)

    Koyani, Rina D.; Andrade, Mariana; Quester, Katrin; Gaytán, Paul; Huerta-Saquero, Alejandro; Vazquez-Duhalt, Rafael

    2018-04-01

    Chitosan nanoparticles have a huge potential as nanocarriers for environmental and biomedical purposes. Protein encapsulation in nano-sized chitosan provides protection against inactivation, proteolysis, and other alterations due to environmental conditions, as well as the possibility to be targeted to specific tissues by ligand functionalization. In this work, we demonstrate that the chemical modification of the protein surface enhances the protein loading in chitosan nanocarriers. Encapsulation of green fluorescent protein and the cytochrome P450 was studied. The increase of electrostatic interactions between the free amino groups of chitosan and the increased number of free carboxylic groups in the protein surface enhance the protein loading, protein retention, and, thus, the enzymatic activity of chitosan nanoparticles. The chemical modification of protein surface with malonic acid moieties reduced drastically the protein isoelectric point increasing the protein interaction with the polycationic biomaterial and chitosan. The chemical modification of protein does not alter the morphology of chitosan nanoparticles that showed an average diameter of 18 nm, spheroidal in shape, and smooth surfaced. The strategy of chemical modification of protein surface, shown here, is a simple and efficient technique to enhance the protein loading in chitosan nanoparticles. This technique could be used for other nanoparticles based on polycationic or polyanionic materials. The increase of protein loading improves, doubtless, the performance of protein-loaded chitosan nanoparticles for biotechnological and biomedical applications.

  3. Surface modification and characterization Collaborative Research Center at ORNL

    International Nuclear Information System (INIS)

    1986-01-01

    The Surface Modification and Characterization Collaborative Research Center (SMAC/CRC) is a unique facility for the alteration and characterization of the near-surface properties of materials. The SMAC/CRC facility is equipped with particle accelerators and high-powered lasers which can be used to improve the physical, electrical, and/or chemical properties of solids and to create unique new materials not possible to obtain with conventional ''equilibrium'' processing techniques. Surface modification is achieved using such techniques as ion implantation doping, ion beam mixing, laser mixing, ion deposition, and laser annealing

  4. Effects of aluminium surface morphology and chemical modification on wettability

    DEFF Research Database (Denmark)

    Rahimi, Maral; Fojan, Peter; Gurevich, Leonid

    2014-01-01

    -life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition...... of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types...

  5. Surface modification for interaction study with bacteria and preosteoblast cells

    Science.gov (United States)

    Song, Qing

    Surface modification plays a pivotal role in bioengineering. Polymer coatings can provide biocompatibility and biofunctionalities to biomaterials through surface modification. In this dissertation, initiated chemical vapor deposition (iCVD) was utilized to coat two-dimensional (2D) and three-dimensional (3D) substrates with differently charged polyelectrolytes in order to generate antimicrobial and osteocompatible biomaterials. ICVD is a modified CVD technique that enables surface modification in an all-dry condition without substrate damage and solvent contamination. The free-radical polymerization allows the vinyl polymers to conformally coat on various micro- and nano-structured substrates and maintains the delicate structure of the functional groups. The vapor deposition of polycations provided antimicrobial activity to planar and porous substrates through destroying the negatively charged bacterial membrane and brought about high contact-killing efficiency (99.99%) against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli. Additionally, the polyampholytes synthesized by iCVD exhibited excellent antifouling performance against the adhesion of Gram-positive Listeria innocua and Gram-negative E. coli in phosphate buffered saline (PBS). Their antifouling activities were attributed to the electrostatic interaction and hydration layers that served as physical and energetic barriers to prevent bacterial adhesion. The contact-killing and antifouling polymers synthesized by iCVD can be applied to surface modification of food processing equipment and medical devices with the aim of reducing foodborne diseases and medical infections. Moreover, the charged polyelectrolyte modified 2D polystyrene surfaces displayed good osteocompatibility and enhanced osteogenesis of preosteoblast cells than the un-modified polystyrene surface. In order to promote osteoinduction of hydroxyapatite (HA) scaffolds, bioinspired polymer-controlled mineralization was conducted

  6. Printing-assisted surface modifications of patterned ultrafiltration membranes

    International Nuclear Information System (INIS)

    Wardrip, Nathaniel C.; Dsouza, Melissa; Urgun-Demirtas, Meltem; Snyder, Seth W.

    2016-01-01

    Understanding and restricting microbial surface attachment will enhance wastewater treatment with membranes. We report a maskless lithographic patterning technique for the generation of patterned polymer coatings on ultrafiltration membranes. Polyethylene glycol, zwitterionic, or negatively charged hydrophilic polymer compositions in parallel- or perpendicular-striped patterns with respect to feed flow were evaluated using wastewater. Membrane fouling was dependent on the orientation and chemical composition of the coatings. Modifications reduced alpha diversity in the attached microbial community (Shannon indices decreased from 2.63 to 1.89) which nevertheless increased with filtration time. Sphingomonas species, which condition membrane surfaces and facilitate cellular adhesion, were depleted in all modified membranes. Microbial community structure was significantly different between control, different patterns, and different chemistries. Lastly, this study broadens the tools for surface modification of membranes with polymer coatings and for understanding and optimization of antifouling surfaces.

  7. Surface modification by preparation of buffer zone in glow-discharge plasma

    International Nuclear Information System (INIS)

    Cho, D.L.

    1986-01-01

    Reactive species, energetic particles, and uv radiation in the plasma created by a glow discharge strongly interact with solid surfaces under the influence of the plasma. As a result of the strong interaction, various physical and chemical reactions, unique and advantageous for the surface modification of solid materials, occur on the solid surfaces. The surface modification is carried out through formation of a thin buffering layer on the solid surface. The preparation of a buffer zone on solid surfaces for surface modification is described. Two kinds of a buffer zone are prepared by plasma polymerization, or simultaneous sputter deposition of electrode material with plasma polymerization: a transitional buffer zone and a graded buffer zone. Important factors for preparation of the buffer zone (pre-conditioning of a substrate surface, thin-film deposition, post-treatment of the film, magnetron discharge, energy input, geometry of a substrate and a plasma) are discussed

  8. Surface modification and endothelialization of biomaterials as potential scaffolds for vascular tissue engineering applications.

    Science.gov (United States)

    Ren, Xiangkui; Feng, Yakai; Guo, Jintang; Wang, Haixia; Li, Qian; Yang, Jing; Hao, Xuefang; Lv, Juan; Ma, Nan; Li, Wenzhong

    2015-08-07

    Surface modification and endothelialization of vascular biomaterials are common approaches that are used to both resist the nonspecific adhesion of proteins and improve the hemocompatibility and long-term patency of artificial vascular grafts. Surface modification of vascular grafts using hydrophilic poly(ethylene glycol), zwitterionic polymers, heparin or other bioactive molecules can efficiently enhance hemocompatibility, and consequently prevent thrombosis on artificial vascular grafts. However, these modified surfaces may be excessively hydrophilic, which limits initial vascular endothelial cell adhesion and formation of a confluent endothelial lining. Therefore, the improvement of endothelialization on these grafts by chemical modification with specific peptides and genes is now arousing more and more interest. Several active peptides, such as RGD, CAG, REDV and YIGSR, can be specifically recognized by endothelial cells. Consequently, graft surfaces that are modified by these peptides can exhibit targeting selectivity for the adhesion of endothelial cells, and genes can be delivered by targeting carriers to specific tissues to enhance the promotion and regeneration of blood vessels. These methods could effectively accelerate selective endothelial cell recruitment and functional endothelialization. In this review, recent developments in the surface modification and endothelialization of biomaterials in vascular tissue engineering are summarized. Both gene engineering and targeting ligand immobilization are promising methods to improve the clinical outcome of artificial vascular grafts.

  9. Research Progress of Optical Fabrication and Surface-Microstructure Modification of SiC

    Directory of Open Access Journals (Sweden)

    Fang Jiang

    2012-01-01

    Full Text Available SiC has become the best candidate material for space mirror and optical devices due to a series of favorable physical and chemical properties. Fine surface optical quality with the surface roughness (RMS less than 1 nm is necessary for fine optical application. However, various defects are present in SiC ceramics, and it is very difficult to polish SiC ceramic matrix with the 1 nm RMS. Surface modification of SiC ceramics must be done on the SiC substrate. Four kinds of surface-modification routes including the hot pressed glass, the C/SiC clapping, SiC clapping, and Si clapping on SiC surface have been reported and reviewed here. The methods of surface modification, the mechanism of preparation, and the disadvantages and advantages are focused on in this paper. In our view, PVD Si is the best choice for surface modification of SiC mirror.

  10. Surface Topographical Modification of Coronary Stent: A Review

    Science.gov (United States)

    Tan, C. H.; Muhamad, N.; Abdullah, M. M. A. B.

    2017-06-01

    Driven by the urge of mediating the inflammatory response from coronary stent implant to improve patency rates of the current coronary stent, concern has been focusing on reducing the risk of in-stent restenosis and thrombosis for long-term safety. Surface modification approach has been found to carry great potential due to the surface is the vital parts that act as a buffer layer between the biomaterial and the organic material like blood and vessel tissues. Nevertheless, manipulating cell response in situ using physical patterning is very complex as the exact mechanism were yet elucidated. Thus, the aim of this review is to summarise the recent efforts on modifying the surface topography of coronary stent at the micro- and nanometer scale with the purpose of inducing rapid in situ endothelialization to regenerate a healthy endothelium layer on biomaterial surface. In particular, a discussion on the surface patterns that have been investigated on cell selective behaviour together with the methods used to generate them are presented. Furthermore, the probable future work involving the surface modification of coronary stent were indicated.

  11. Surface modification of porous titanium with rice husk as space holder

    Science.gov (United States)

    Wang, Xinsheng; Hou, Junjian; Liu, Yanpei

    2018-06-01

    Porous titanium was characterized after its surface modification by acid and alkali solution immersion. The results show that the acid surface treatment caused the emergence of flocculent sodium titanate and induced apatite formation. The surface modification of porous titanium promotes biological activation, and the application of porous titanium is also improved as an implant material because of the existence of C and Si.

  12. PES Surface Modification Using Green Chemistry: New Generation of Antifouling Membranes.

    Science.gov (United States)

    Nady, Norhan

    2016-04-18

    A major limitation in using membrane-based separation processes is the loss of performance due to membrane fouling. This drawback can be addressed thanks to surface modification treatments. A new and promising surface modification using green chemistry has been recently investigated. This modification is carried out at room temperature and in aqueous medium using green catalyst (enzyme) and nontoxic modifier, which can be safely labelled "green surface modification". This modification can be considered as a nucleus of new generation of antifouling membranes and surfaces. In the current research, ferulic acid modifier and laccase bio-catalyst were used to make poly(ethersulfone) (PES) membrane less vulnerable to protein adsorption. The blank and modified PES membranes are evaluated based on e.g., their flux and protein repellence. Both the blank and the modified PES membranes (or laminated PES on silicon dioxide surface) are characterized using many techniques e.g., SEM, EDX, XPS and SPM, etc. The pure water flux of the most modified membranes was reduced by 10% on average relative to the blank membrane, and around a 94% reduction in protein adsorption was determined. In the conclusions section, a comparison between three modifiers-ferulic acid, and two other previously used modifiers (4-hydroxybenzoic acid and gallic acid)-is presented.

  13. Nanoscale surface modification of Li-rich layered oxides for high-capacity cathodes in Li-ion batteries

    Science.gov (United States)

    Lan, Xiwei; Xin, Yue; Wang, Libin; Hu, Xianluo

    2018-03-01

    Li-rich layered oxides (LLOs) have been developed as a high-capacity cathode material for Li-ion batteries, but the structural complexity and unique initial charging behavior lead to several problems including large initial capacity loss, capacity and voltage fading, poor cyclability, and inferior rate capability. Since the surface conditions are critical to electrochemical performance and the drawbacks, nanoscale surface modification for improving LLO's properties is a general strategy. This review mainly summarizes the surface modification of LLOs and classifies them into three types of surface pre-treatment, surface gradient doping, and surface coating. Surface pre-treatment usually introduces removal of Li2O for lower irreversible capacity while surface doping is aimed to stabilize the structure during electrochemical cycling. Surface coating layers with different properties, protective layers to suppress the interface side reaction, coating layers related to structural transformation, and electronic/ionic conductive layers for better rate capability, can avoid the shortcomings of LLOs. In addition to surface modification for performance enhancement, other strategies can also be investigated to achieve high-performance LLO-based cathode materials.

  14. Surface modifications induced by pulsed-laser texturing—Influence of laser impact on the surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Costil, S., E-mail: sophie.costil@utbm.fr [IRTES-LERMPS, Université de Technologie de Belfort - Montbéliard, site de Sévenans, 90010 Belfort Cedex (France); Lamraoui, A.; Langlade, C. [IRTES-LERMPS, Université de Technologie de Belfort - Montbéliard, site de Sévenans, 90010 Belfort Cedex (France); Heintz, O.; Oltra, R. [ICB, Université de Bourgogne, 21078 Dijon Cedex (France)

    2014-01-01

    Laser cleaning technology provides a safe, environmentally friendly and very cost effective way to improve cleaning and surface preparation of metallic materials. Compared with efficient cleaning processes, it can avoid the disadvantages of ductile materials prepared by conventional technologies (cracks induced by sand-blasting for example) and treat only some selected areas (due to the optical fibers). By this way, laser technology could have several advantages and expand the range of thermal spraying. Moreover, new generations of lasers (fiber laser, disc laser) allow the development of new methods. Besides a significant bulk reduction, no maintenance, low operating cost, laser fibers can introduce alternative treatments. Combining a short-pulse laser with a scanner allows new applications in terms of surface preparation. By multiplying impacts using scanning laser, it is possible to shape the substrate surface to improve the coating adhesion as well as the mechanical behaviour. In addition, during the interactions of the laser beam with metallic surfaces, several modifications can be induced and particularly thermal effects. Indeed, under ambient conditions, a limited oxidation of the clean surface can occur. This phenomenon has been investigated in detail for silicon but few works have been reported concerning metallic materials. This paper aims at studying the surface modifications induced on aluminium alloy substrates after laser texturing. After morphological observations (SEM), a deeper surface analysis will be performed using XPS (X-ray photoelectron spectroscopy) measures and microhardness testing.

  15. Effects of surface atomistic modification on mechanical properties of gold nanowires

    International Nuclear Information System (INIS)

    Sun, Xiao-Yu; Xu, Yuanjie; Wang, Gang-Feng; Gu, Yuantong; Feng, Xi-Qiao

    2015-01-01

    Highlights: • Molecular dynamics simulations of surface modification effect of Au nanowires. • Surface modification can greatly affect the mechanical properties of nanowires. • Core–shell model is used to elucidate the effect of residual surface stress. - Abstract: Modulation of the physical and mechanical properties of nanowires is a challenging issue for their technological applications. In this paper, we investigate the effects of surface modification on the mechanical properties of gold nanowires by performing molecular dynamics simulations. It is found that by modifying a small density of silver atoms to the surface of a gold nanowire, the residual surface stress state can be altered, rendering a great improvement of its plastic yield strength. This finding is in good agreement with experimental measurements. The underlying physical mechanisms are analyzed by a core–shell nanowire model. The results are helpful for the design and optimization of advanced nanomaterial with superior mechanical properties

  16. Surface modification of ceramics and metals by ion implantation combined with plasma irradiation

    International Nuclear Information System (INIS)

    Miyagawa, Soji; Miyagawa, Yoshiko; Nakao, Setsuo; Ikeyama, Masami; Saitoh, Kazuo

    2000-01-01

    To develop a new surface modification technique using ion implantation combined with plasma irradiation, thin film formation by IBAD (Ion Beam Assisted Deposition) and atom relocation processes such as radiation enhanced diffusion and ion beam mixing under high dose implantation have been studied. It was confirmed that the computer simulation code, dynamic-SASAMAL (IBAD version) developed in this research, is quite useful to evaluate ballistic components in film formation by high dose implantation on ceramics and metals, by ion beam mixing of metal-ceramics bi-layer and by the IBAD method including hydrocarbon deposition. Surface modification process of SiC by simultaneous irradiation of ions with a radical beam has also been studied. A composite of SiC and β-Si 3 N 4 was found to be formed on a SiC surface by hot implantation of nitrogen. The amount of β- Si 3 N 4 crystallites increased with increasing the dosage of the hydrogen radical beam during nitrogen implantation. (author)

  17. Laser-Based Surface Modification of Microstructure for Carbon Fiber-Reinforced Plastics

    Science.gov (United States)

    Yang, Wenfeng; Sun, Ting; Cao, Yu; Li, Shaolong; Liu, Chang; Tang, Qingru

    2018-05-01

    Bonding repair is a powerful feature of carbon fiber-reinforced plastics (CFRP). Based on the theory of interface bonding, the interface adhesion strength and reliability of the CFRP structure will be directly affected by the microscopic features of the CFRP surface, including the microstructure, physical, and chemical characteristics. In this paper, laser-based surface modification was compared to Peel-ply, grinding, and polishing to comparatively evaluate the surface microstructure of CFRP. The surface microstructure, morphology, fiber damage, height and space parameters were investigated by scanning electron microscopy (SEM) and laser confocal microscopy (LCM). Relative to the conventional grinding process, laser modification of the CFRP surface can result in more uniform resin removal and better processing control and repeatability. This decreases the adverse impact of surface fiber fractures and secondary damage. The surface properties were significantly optimized, which has been reflected such things as the obvious improvement of surface roughness, microstructure uniformity, and actual area. The improved surface microstructure based on laser modification is more conducive to interface bonding of CFRP structure repair. This can enhance the interfacial adhesion strength and reliability of repair.

  18. Modification of Ti6Al4V surface by diazonium compounds

    Science.gov (United States)

    Sandomierski, Mariusz; Buchwald, Tomasz; Strzemiecka, Beata; Voelkel, Adam

    2018-02-01

    Ti6Al4V alloy is the most commonly used in orthopedic industry as an endoprosthesis. Ti6Al4V exhibits good mechanical properties, except the abrasion resistance. Surface modification of Ti6Al4V in order to obtain organic layer, and then the attachment of the polymer, can allow for overcoming this problem. The aim of the work was the modification of Ti6Al4V surface by diazonium compounds: salt or cation generated in situ and examine the influence of the reducing agent - ascorbic acid, and the temperature of reaction on modification process. Moreover, the simulated body fluid was used for the assessment of the organic layer stability on Ti6Al4V surface. The evaluation of the modification was carried out using the following methods: Raman microspectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Higher temperature of modification by 4-hydroxymethylbenzenediazonium cation, provides the largest amount of organic layer on the Ti6Al4V alloy. In the case of the Ti6Al4V modified by Variamine Blue B salt, the amount of organic layer is not dependent on the reaction condition. Moreover, the ascorbic acid and the presence of TiO2 does not effect on the modification. The modified surface is completely coated with the organic layer which is stable in simulated body fluid.

  19. Surface modification of steels by electrical discharge treatment in electrolyte

    International Nuclear Information System (INIS)

    Krastev, D.; Paunov, V.; Yordanov, B.; Lazarova, V.

    2013-01-01

    Full text: In this work are discussed some experimental data about the influence of applied electrical discharge treatment in electrolyte on the surface structure of steels. The electrical discharge treatment of steel surface in electrolyte gives a modified structure with specific combination of characteristics in result of nonequilibrium transformations. The modification goes by a high energy thermal process in a very small volume on the metallic surface involving melting, vaporisation, activation and alloying in electrical discharges, and after that cooling of this surface with high rate in the electrolyte. The surface layers obtain a different structure in comparison with the metal matrix and are with higher hardness, wear resistance and corrosion resistance. key words: surface modification, electrical discharge treatment in electrolyte, steels

  20. Surface modifications of polypropylene by high energy carbon ions

    International Nuclear Information System (INIS)

    Saha, A.; Chakraborty, V.; Dutta, R.K.; Chintalapudi, S.N.

    2000-01-01

    Polypropylene was irradiated with 12 C ions of 3.6 and 5.4 MeV energies using 3 MV tandem accelerator. The surface modification was investigated by Scanning Electron Microscopy (SEM). Optical changes were monitored by UV-VIS and FTIR spectroscopy. At the lowest ion fluence, only blister formation of various sizes (1-6 μm) was observed. Polymer when irradiated at a fluence of 1x10 14 ions/cm 2 exhibited a network structure. A comparative study on dose dependence of surface and bulk modification has been described. (author)

  1. PREFACE Surface Modifications and Functionalization of Materials for Biomedical Applications

    Science.gov (United States)

    Endrino, Jose Luis; Puértolas, Jose A.; Albella, Jose M.

    2010-11-01

    Conference photograph This special issue contains selected papers which were presented as invited and contributed communications at the workshop entitled 'Surface modification and functionalization of materials for biomedical applications' (BIO-COAT 2010) which was held on 24 June 2010 in Zaragoza (Spain). The surface of a material plays a major role in its interaction with the biological medium. Processes related to the mechanical stability of articular devices in contact, osseointegration, thrombogenicity, corrosion and leaching, or the inflammatory response of rejection of a material, are clearly conditioned by the surface properties. Therefore, the modification or functionalization of surfaces can have an important impact on these issues. New techniques for functionalization by thin film deposition or surface treatments help to improve superficial properties, while understanding the interaction of the surface-biological medium is critical for their application in new devices. Jointly organized by the Spanish Materials Research Society, BIO-COAT 2010 provided an open forum to discuss the progress and latest developments in thin film processing and the engineering of biomaterials. Invited lectures were particularly aimed at providing overviews on scientific topics and were given by recognized world-class scientists. Two of them have contributed with a proceedings article to this selected collection (articles 012001 and 012008). The contributed communications were focused on particular cutting-edge aspects of thin film science and functionalization technologies for biomaterials, showing the major scientific push of Spanish research groups in the field. The 2010 BIO-COAT conference was organized along four main topics: (1) functionalization and texture on surfaces, (2) tribology and corrosion, (3) the surface modification of biomaterials, and (4) surface-biological environment interactions. The papers published in this volume were accepted for publication after

  2. Enhancing the Properties of Carbon and Gold Substrates by Surface Modification

    Energy Technology Data Exchange (ETDEWEB)

    Harnisch, Jennifer Anne [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol (BHT) SAMs. BHT chemisorbs to the gold surface in a previously unprecedented planar fashion. Carbon and gold substrates can be chemically altered by several methodologies resulting in new surface properties. The development of modification protocols and their application in the analytical arena is considered herein.

  3. Flotation separation of polyvinyl chloride and polyethylene terephthalate plastics combined with surface modification for recycling.

    Science.gov (United States)

    Wang, Chongqing; Wang, Hui; Fu, Jiangang; Zhang, Lingling; Luo, Chengcheng; Liu, Younian

    2015-11-01

    Surface modification with potassium permanganate (KMnO4) solution was developed for separation of polyvinyl chloride (PVC) and polyethylene terephthalate (PET) waste plastics. The floatability of PVC decreases with increasing of KMnO4 concentration, treatment time, temperature and stirring rate, while that of PET is unaffected. Fourier transform infrared (FT-IR) analysis confirms that mechanism of surface modification may be due to oxidization reactions occurred on PVC surface. The optimum conditions are KMnO4 concentration 1.25 mM/L, treatment time 50 min, temperature 60°C, stirring rate 300 r/min, frother concentration 17.5 g/L and flotation time 1 min. PVC and PET with different particle sizes were separated efficiently through two-stage flotation. Additionally, after ultrasonic assisted surface modification, separation of PVC and PET with different mass ratios was obtained efficiently through one-stage flotation. The purity and the recovery of the obtained products after flotation separation are up to 99.30% and 99.73%, respectively. A flotation process was designed for flotation separation of PVC and PET plastics combined with surface modification. This study provides technical insights into physical separation of plastic wastes for recycling industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Chemical modifications of Au/SiO2 template substrates for patterned biofunctional surfaces.

    Science.gov (United States)

    Briand, Elisabeth; Humblot, Vincent; Landoulsi, Jessem; Petronis, Sarunas; Pradier, Claire-Marie; Kasemo, Bengt; Svedhem, Sofia

    2011-01-18

    The aim of this work was to create patterned surfaces for localized and specific biochemical recognition. For this purpose, we have developed a protocol for orthogonal and material-selective surface modifications of microfabricated patterned surfaces composed of SiO(2) areas (100 μm diameter) surrounded by Au. The SiO(2) spots were chemically modified by a sequence of reactions (silanization using an amine-terminated silane (APTES), followed by amine coupling of a biotin analogue and biospecific recognition) to achieve efficient immobilization of streptavidin in a functional form. The surrounding Au was rendered inert to protein adsorption by modification by HS(CH(2))(10)CONH(CH(2))(2)(OCH(2)CH(2))(7)OH (thiol-OEG). The surface modification protocol was developed by testing separately homogeneous SiO(2) and Au surfaces, to obtain the two following results: (i) SiO(2) surfaces which allowed the grafting of streptavidin, and subsequent immobilization of biotinylated antibodies, and (ii) Au surfaces showing almost no affinity for the same streptavidin and antibody solutions. The surface interactions were monitored by quartz crystal microbalance with dissipation monitoring (QCM-D), and chemical analyses were performed by polarization modulation-reflexion absorption infrared spectroscopy (PM-RAIRS) and X-ray photoelectron spectroscopy (XPS) to assess the validity of the initial orthogonal assembly of APTES and thiol-OEG. Eventually, microscopy imaging of the modified Au/SiO(2) patterned substrates validated the specific binding of streptavidin on the SiO(2)/APTES areas, as well as the subsequent binding of biotinylated anti-rIgG and further detection of fluorescent rIgG on the functionalized SiO(2) areas. These results demonstrate a successful protocol for the preparation of patterned biofunctional surfaces, based on microfabricated Au/SiO(2) templates and supported by careful surface analysis. The strong immobilization of the biomolecules resulting from the described

  5. Surface Modification of Polymer Substrates for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Oldřich Neděla

    2017-09-01

    Full Text Available While polymers are widely utilized materials in the biomedical industry, they are rarely used in an unmodified state. Some kind of a surface treatment is often necessary to achieve properties suitable for specific applications. There are multiple methods of surface treatment, each with their own pros and cons, such as plasma and laser treatment, UV lamp modification, etching, grafting, metallization, ion sputtering and others. An appropriate treatment can change the physico-chemical properties of the surface of a polymer in a way that makes it attractive for a variety of biological compounds, or, on the contrary, makes the polymer exhibit antibacterial or cytotoxic properties, thus making the polymer usable in a variety of biomedical applications. This review examines four popular methods of polymer surface modification: laser treatment, ion implantation, plasma treatment and nanoparticle grafting. Surface treatment-induced changes of the physico-chemical properties, morphology, chemical composition and biocompatibility of a variety of polymer substrates are studied. Relevant biological methods are used to determine the influence of various surface treatments and grafting processes on the biocompatibility of the new surfaces—mammalian cell adhesion and proliferation is studied as well as other potential applications of the surface-treated polymer substrates in the biomedical industry.

  6. Nanoscale surface modifications to control capillary flow characteristics in PMMA microfluidic devices

    Directory of Open Access Journals (Sweden)

    Mukhopadhyay Subhadeep

    2011-01-01

    Full Text Available Abstract Polymethylmethacrylate (PMMA microfluidic devices have been fabricated using a hot embossing technique to incorporate micro-pillar features on the bottom wall of the device which when combined with either a plasma treatment or the coating of a diamond-like carbon (DLC film presents a range of surface modification profiles. Experimental results presented in detail the surface modifications in the form of distinct changes in the static water contact angle across a range from 44.3 to 81.2 when compared to pristine PMMA surfaces. Additionally, capillary flow of water (dyed to aid visualization through the microfluidic devices was recorded and analyzed to provide comparison data between filling time of a microfluidic chamber and surface modification characteristics, including the effects of surface energy and surface roughness on the microfluidic flow. We have experimentally demonstrated that fluid flow and thus filling time for the microfluidic device was significantly faster for the device with surface modifications that resulted in a lower static contact angle, and also that the incorporation of micro-pillars into a fluidic device increases the filling time when compared to comparative devices.

  7. New surface modification method of bio-titanium alloy by EB polishing

    International Nuclear Information System (INIS)

    Okada, Akira; Uno, Yoshiyuki; Iio, Atsuo; Fujiwara, Kunihiko; Doi, Kenji

    2008-01-01

    A new surface modification for bio-titanium alloy products by electron beam (EB) polishing is proposed. In this EB polishing method, high energy density EB can be irradiated without concentrating the beam. Therefore, large-area EB with a maximum diameter of 60 mm can be used for instantaneously melting or evaporating metal surface. Experimental results made it clear that surface characteristics, such as repellency, corrosion resistance and coefficient of friction could be improved simultaneously with the surface smoothing in a few minutes under a proper condition. Therefore, EB polishing method has a possibility of high efficient surface smoothing and surface modification process for bio-titanium alloy. (author)

  8. Plasma polymerization surface modification of Carbon black and its effect in elastomers

    NARCIS (Netherlands)

    Mathew, T.; Datta, Rabin; Dierkes, Wilma K.; Talma, Auke; Ooij, W.J.; Noordermeer, Jacobus W.M.

    2011-01-01

    Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known

  9. Nanotubular surface modification of metallic implants via electrochemical anodization technique.

    Science.gov (United States)

    Wang, Lu-Ning; Jin, Ming; Zheng, Yudong; Guan, Yueping; Lu, Xin; Luo, Jing-Li

    2014-01-01

    Due to increased awareness and interest in the biomedical implant field as a result of an aging population, research in the field of implantable devices has grown rapidly in the last few decades. Among the biomedical implants, metallic implant materials have been widely used to replace disordered bony tissues in orthopedic and orthodontic surgeries. The clinical success of implants is closely related to their early osseointegration (ie, the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant), which relies heavily on the surface condition of the implant. Electrochemical techniques for modifying biomedical implants are relatively simple, cost-effective, and appropriate for implants with complex shapes. Recently, metal oxide nanotubular arrays via electrochemical anodization have become an attractive technique to build up on metallic implants to enhance the biocompatibility and bioactivity. This article will thoroughly review the relevance of electrochemical anodization techniques for the modification of metallic implant surfaces in nanoscale, and cover the electrochemical anodization techniques used in the development of the types of nanotubular/nanoporous modification achievable via electrochemical approaches, which hold tremendous potential for bio-implant applications. In vitro and in vivo studies using metallic oxide nanotubes are also presented, revealing the potential of nanotubes in biomedical applications. Finally, an outlook of future growth of research in metallic oxide nanotubular arrays is provided. This article will therefore provide researchers with an in-depth understanding of electrochemical anodization modification and provide guidance regarding the design and tuning of new materials to achieve a desired performance and reliable biocompatibility.

  10. Femtosecond laser-induced surface wettability modification of polystyrene surface

    Science.gov (United States)

    Wang, Bing; Wang, XinCai; Zheng, HongYu; Lam, YeeCheong

    2016-12-01

    In this paper, we demonstrated a simple method to create either a hydrophilic or hydrophobic surface. With femtosecond laser irradiation at different laser parameters, the water contact angle (WCA) on polystyrene's surface can be modified to either 12.7° or 156.2° from its original WCA of 88.2°. With properly spaced micro-pits created, the surface became hydrophilic probably due to the spread of the water droplets into the micro-pits. While with properly spaced micro-grooves created, the surface became rough and more hydrophobic. We investigated the effect of laser parameters on WCAs and analyzed the laser-treated surface roughness, profiles and chemical bonds by surface profilometer, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). For the laser-treated surface with low roughness, the polar (such as C—O, C=O, and O—C=O bonds) and non-polar (such as C—C or C—H bonds) groups were found to be responsible for the wettability changes. While for a rough surface, the surface roughness or the surface topography structure played a more significant role in the changes of the surface WCA. The mechanisms involved in the laser surface wettability modification process were discussed.

  11. PES Surface Modification Using Green Chemistry: New Generation of Antifouling Membranes

    Directory of Open Access Journals (Sweden)

    Norhan Nady

    2016-04-01

    Full Text Available A major limitation in using membrane-based separation processes is the loss of performance due to membrane fouling. This drawback can be addressed thanks to surface modification treatments. A new and promising surface modification using green chemistry has been recently investigated. This modification is carried out at room temperature and in aqueous medium using green catalyst (enzyme and nontoxic modifier, which can be safely labelled “green surface modification”. This modification can be considered as a nucleus of new generation of antifouling membranes and surfaces. In the current research, ferulic acid modifier and laccase bio-catalyst were used to make poly(ethersulfone (PES membrane less vulnerable to protein adsorption. The blank and modified PES membranes are evaluated based on e.g., their flux and protein repellence. Both the blank and the modified PES membranes (or laminated PES on silicon dioxide surface are characterized using many techniques e.g., SEM, EDX, XPS and SPM, etc. The pure water flux of the most modified membranes was reduced by 10% on average relative to the blank membrane, and around a 94% reduction in protein adsorption was determined. In the conclusions section, a comparison between three modifiers—ferulic acid, and two other previously used modifiers (4-hydroxybenzoic acid and gallic acid—is presented.

  12. Effect of surface modification and hybridization on dynamic ...

    Indian Academy of Sciences (India)

    Epoxy; Roystonea regia; glass; surface modification; hybridization; dynamic mechanical ... other advantages such as light weight, low cost, high specific ... ful technique to study the mechanical behaviour of mate- ... The test reveals response.

  13. Surface modification on silicon with chitosan and biological research

    International Nuclear Information System (INIS)

    Lue Xiaoying; Cui Wei; Huang Yan; Zhao Yi; Wang Zhigong

    2009-01-01

    The aim of the present study was to investigate the effect of chitosan modification of silicon (Si) on protein adsorption, cell adhesion and cell proliferation. Chitosan was first immobilized on the Si surface through a (3-aminopropyl)triethoxysilane (APTES) bridge. The surface was then characterized by contact angle measurement, atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectroscopy (EDX). The amount of protein adsorbed on the native Si and chitosan-modified Si surface was evaluated by a modified Coomassie brilliant blue (CBB) protein assay. The adhesion and proliferation behavior of L-929 and pc12 cells were then assessed by microscopy and methylthiazoltetrazolium (MTT) tests. The results showed that the chitosan modification could resist protein adsorption and inhibit the adhesion and proliferation of two kinds of cells on Si.

  14. Augmented liver targeting of exosomes by surface modification with cationized pullulan.

    Science.gov (United States)

    Tamura, Ryo; Uemoto, Shinji; Tabata, Yasuhiko

    2017-07-15

    Exosomes are membrane nanoparticles containing biological substances that are employed as therapeutics in experimental inflammatory models. Surface modification of exosomes for better tissue targetability and enhancement of their therapeutic ability was recently attempted mainly using gene transfection techniques. Here, we show for the first time that the surface modification of exosomes with cationized pullulan, which has the ability to target hepatocyte asialoglycoprotein receptors, can target injured liver and enhance the therapeutic effect of exosomes. Surface modification can be achieved by a simple mixing of original exosomes and cationized pullulan and through an electrostatic interaction of both substances. The exosomes modified with cationized pullulan were internalized into HepG2 cells in vitro to a significantly greater extent than unmodified ones and this internalization was induced through the asialoglycoprotein receptor that was specifically expressed on HepG2 cells and hepatocytes. When injected intravenously into mice with concanavalin A-induced liver injury, the modified exosomes accumulated in the liver tissue, resulting in an enhanced anti-inflammatory effect in vivo. It is concluded that the surface modification with cationized pullulan promoted accumulation of the exosomes in the liver and the subsequent biological function, resulting in a greater therapeutic effect on liver injury. Exosomes have shown potentials as therapeutics for various inflammatory disease models. This study is the first to show the specific accumulation of exosomes in the liver and enhanced anti-inflammatory effect via the surface modification of exosomes using pullulan, which is specifically recognized by the asialoglycoprotein receptor (AGPR) on HepG2 cells and hepatocytes. The pullulan was expressed on the surface of PKH-labeled exosomes, and it led increased accumulation of PKH into HepG2 cells, whereas the accumulation was canceled by AGPR inhibitor. In the mouse

  15. Thermal performance enhancement of erythritol/carbon foam composites via surface modification of carbon foam

    Science.gov (United States)

    Li, Junfeng; Lu, Wu; Luo, Zhengping; Zeng, Yibing

    2017-03-01

    The thermal performance of the erythritol/carbon foam composites, including thermal diffusivity, thermal capacity, thermal conductivity and latent heat, were investigated via surface modification of carbon foam using hydrogen peroxide as oxider. It was found that the surface modification enhanced the wetting ability of carbon foam surface to the liquid erythritol of the carbon foam surface and promoted the increase of erythritol content in the erythritol/carbon foam composites. The dense interfaces were formed between erythritol and carbon foam, which is due to that the formation of oxygen functional groups C=O and C-OH on the carbon surface increased the surface polarity and reduced the interface resistance of carbon foam surface to the liquid erythritol. The latent heat of the erythritol/carbon foam composites increased from 202.0 to 217.2 J/g through surface modification of carbon foam. The thermal conductivity of the erythritol/carbon foam composite before and after surface modification further increased from 40.35 to 51.05 W/(m·K). The supercooling degree of erythritol also had a large decrease from 97 to 54 °C. Additionally, the simple and effective surface modification method of carbon foam provided an extendable way to enhance the thermal performances of the composites composed of carbon foams and PCMs.

  16. Nano-scale surface modification of materials with slow, highly charged ion beams

    International Nuclear Information System (INIS)

    Sakurai, M.; Tona, M.; Takahashi, S.; Watanabe, H.; Nakamura, N.; Yoshiyasu, N.; Yamada, C.; Ohtani, S.; Sakaue, H.A.; Kawase, Y.; Mitsumori, K.; Terui, T.; Mashiko, S.

    2007-01-01

    Some results on surface modification of Si and graphite with highly charged ions (HCIs) are presented. Modified surfaces were observed using scanning tunneling microscopy. Crater-like structure with a diameter in nm region is formed on a Si(1 1 1)-(7 x 7) surface by the incidence of a single HCI. The protrusion structure is formed on a highly oriented pyrolytic graphite surface on the other hand, and the structure becomes an active site for molecular adsorption. A new, intense HCI source and an experimental apparatus are under development in order to process and observe aligned nanostructures created by the impact of collimated HCI beam

  17. Low-temperature plasma techniques in surface modification of biomaterials

    International Nuclear Information System (INIS)

    Feng Xiangfen; Xie Hankun; Zhang Jing

    2002-01-01

    Since synthetic polymers usually can not meet the biocompatibility and bio-functional demands of the human body, surface treatment is a prerequisite for them to be used as biomaterials. A very effective surface modification method, plasma treatment, is introduced. By immobilizing the bio-active molecules with low temperature plasma, polymer surfaces can be modified to fully satisfy the requirements of biomaterials

  18. Surface defect modification of ZnO quantum dots based on rare earth acetylacetonate and their impacts on optical performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lixi, E-mail: wanglixi_njut@163.com [School of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210009, Jiangsu (China); Jiangsu Collaboration Innovation Center for Advanced Inorganic Function Composites, Nanjing, 210009, Jiangsu (China); Yang, Xiaojuan; Yang, Weimin [School of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210009, Jiangsu (China); Jiangsu Collaboration Innovation Center for Advanced Inorganic Function Composites, Nanjing, 210009, Jiangsu (China); Zhang, Jing [China Geol Survey, Nanjing Ctr, Nanjing, 210016, Jiangsu (China); Zhang, Qitu [School of Materials Science and Engineering, Nanjing Tech University, Nanjing, 210009, Jiangsu (China); Jiangsu Collaboration Innovation Center for Advanced Inorganic Function Composites, Nanjing, 210009, Jiangsu (China); Song, Bo; Wong, Chingping [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, 30332, GA (United States)

    2017-03-15

    Graphical abstract: RE(AcAc){sub 3} (RE = Ce, Dy and Tb) can realize the defects modification of ZnO QDs based on the linkage occurs between the protons of the hydroxyl groups on the surface of ZnO QDs and the π–system of acetylacetone. The color coordinate could be shifted among yellow-green, blue-green, and green region by changing the RE (AcAc){sub 3} ratios. The stable Ce(AcAc){sub 3}/ZnO QDs with average sizes of about 3.0 nm can be obtained. The calculated band gap data also proved the efficient modification of Ce(AcAc){sub 3} for ZnO QDs with the largest variation of band gap energy of 0.039 eV (from 3.583 eV to 3.544 eV). - Highlights: • Defects modification of ZnO QDs based on rare earth acetylacetonate. • Stable Ce(AcAc){sub 3}/ZnO QDs with an average sizes of about 3.0 nm. • The color coordinate could be shifted among yellow-green, blue-green, and green region by changing the RE (AcAc){sub 3} ratios. - Abstract: The surface defect modification has an important effect on the application of ZnO quantum dots, and it has gained much progress in recently years, propelled by the development of additives. Our research efforts are directed toward developing a new surface modification additive RE(AcAc){sub 3} (RE = Ce, Dy, Tb) to achieve fine ZnO QDs and adjust their surface properties. RE(AcAc){sub 3}/ZnO QDs nanostructured materials have been designed and prepared, and particular emphasis has been given to the relation between the surface modification and optical properties. The effects of RE(III) acetylacetonate modification on the FT-IR, TEM images and photoluminescence (PL) spectra were investigated, and the surface defect modification principle and effect were discussed in details. The band gap (E{sub g}) was also calculated to prove the surface modification effect. For the RE(AcAc){sub 3}/ZnO QDs complex materials, stable linkage occurs because of the affinity of −COOH from acetylacetonate anionic ligand to zinc oxide surfaces, with attachment

  19. Long-term stable surface modification of DLC coatings

    Directory of Open Access Journals (Sweden)

    Gotzmann Gaby

    2017-09-01

    Full Text Available The use of coatings based on diamond like carbon (DLC for medical applications was established during the last years. Main advantages of these coatings are its high hardness, good wear and friction behavior and its biocompatibility. Using low-energy electron-beam treatment, we addressed the surface modification of DLC coatings. The aim was to generate new biofunctional surface characteristics that are long-term stable.

  20. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Ki [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Park, Daewon; Kim, Hoonbae [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Hyerim; Park, Heonyong [Department of Molecular Biology, Dankook University, Yongin 448-701 (Korea, Republic of); Kim, Hong Ja [Department of Internal Medicine, Dankook University, Cheonan 330-714 (Korea, Republic of); Jung, Donggeun, E-mail: djung@skku.ac.kr [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-03-01

    Graphical abstract: - Highlights: • The surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts. • Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment using micro plasma discharge. - Abstract: Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature

  1. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    International Nuclear Information System (INIS)

    Cho, Yong Ki; Park, Daewon; Kim, Hoonbae; Lee, Hyerim; Park, Heonyong; Kim, Hong Ja; Jung, Donggeun

    2014-01-01

    Graphical abstract: - Highlights: • The surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts. • Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment using micro plasma discharge. - Abstract: Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature

  2. Improvement of Polypropylene Biological Interactions by using Superhydrophobic Surface Modification

    Directory of Open Access Journals (Sweden)

    E. Shirani

    2018-03-01

    Full Text Available The significance of producing superhydrophobic surfaces through modification of surface chemistry and structure is in preventing or delaying biofilm formation. This is done to improve biocompatibility and chemical and biological properties of the surface by creating micro-nano multilevel rough structure; and to decrease surface free energy by Fault Tolerant Control Strategy (FTCS . Here, we produced a superhydrophobic surface through TiO2 coating and flurosilanization methods. Then, in order to evaluate the physicochemical properties of the modified surfaces, they were characterized by Scanning Electron Microscope (SEM, Fourier Transform Infrared Spectroscopy (FTIR, Contact Angle (CA, cell viability assay (using Hela and MCF-7 cancer cell lines as well as non-cancerous human fibroblast cells by MTT, Bovine Serum Abumin (BSA protein adsorption using Bradford and bacterial adhesion assay (Staphylococcus aureus and Staphylococcus epidermidis using microtiter. Results showed that contact angle and surface energey of superhydrophobic modified surface increased to 150° and decreased to 5.51 mj/m2, respectively due to physicochemical modifications of the surface. In addition, the results showed a substantial reduction in protein adsorption and bacterial cell adhesion in superhydrophobic surface.

  3. Laser and chemical surface modifications of titanium grade 2 for medical application

    Energy Technology Data Exchange (ETDEWEB)

    Kwaśniak, P. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Pura, J., E-mail: jaroslawpura@gmail.com [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Zwolińska, M.; Wieciński, P. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Skarżyński, H.; Olszewski, L. [Institute of Physiology and Pathology of Hearing, Warsaw (Poland); World Hearing Center, Kajetany (Poland); Marczak, J. [Military University of Technology, Institute of Optoelectronics, Warsaw (Poland); Garbacz, H.; Kurzydłowski, K.J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland)

    2015-05-01

    Highlights: • DLIL technique and etching were used for functionalization of Ti grade 2 surface. • Modification was performed on semi-finished flat and curved Ti surfaces. • Modification results in periodic multimodal (micro and nano-size) Ti topography. - Abstract: The article presents combined, chemical and physical approach to titanium surface functionalization designed for biomedical applications. The topography modification has been obtained by employing the double laser beam interference technique and chemical etching. In the outcome, clean and smooth Ti surface as well as periodic striated topography with the roughness range from nano- to micrometers were created. The obtained structures were characterized in terms of shape, roughness, chemical composition, mechanical properties and microstructures. In order to achieve all information, numerous of research methods have been used: scanning electron microscopy, atomic force microscopy, optical profilometry and microhardness measurements. Demonstrated methodology can be used as an effective tool for manufacturing controlled surface structures improving the bone–implants interactions.

  4. Surface modification of food contact materials for processing and packaging applications

    Science.gov (United States)

    Barish, Jeffrey A.

    This body of work investigates various techniques for the surface modification of food contact materials for use in food packaging and processing applications. Nanoscale changes to the surface of polymeric food packaging materials enables changes in adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is used in applications such as antimicrobial or non-fouling materials, biosensors, and active packaging. Non-migratory active packagings, in which bioactive components are tethered to the package, offer the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing non-migratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. Polyethylene glycol (PEG), a biocompatible polymer, is grafted from the surface of ozone treated low-density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine-terminated bioactive molecules can be immobilized. The grafting of PEG onto the surface of polymer packaging films is accomplished by free radical graft polymerization, and to covalently link an amine-terminated molecule to the PEG tether, demonstrating that amine-terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG-grafted LDPE in the development of non-migratory active packaging. Fouling on food contact surfaces during food processing has a significant impact on operating efficiency and can promote biofilm development. Processing raw milk on plate heat exchangers results in significant fouling of proteins as well as minerals, and is exacerbated by the wall heating effect. An electroless nickel coating is co-deposited with polytetrafluoroethylene onto stainless steel to test its ability to resist fouling on a pilot plant scale plate heat exchanger. Further

  5. Surface modification on PMMA : PVDF polyblend: hardening under ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Polyblend; surface modification; microhardness; hardening; plasticization; segmental mobility. 1. Introduction. Polymeric materials have a specific feature of stability towards various aggressive chemical environments, which depends on a multiplicity of factors like structure and nature of the polymers and chemical ...

  6. Microwave plasma induced surface modification of diamond-like carbon films

    Science.gov (United States)

    Rao Polaki, Shyamala; Kumar, Niranjan; Gopala Krishna, Nanda; Madapu, Kishore; Kamruddin, Mohamed; Dash, Sitaram; Tyagi, Ashok Kumar

    2017-12-01

    Tailoring the surface of diamond-like carbon (DLC) film is technically relevant for altering the physical and chemical properties, desirable for useful applications. A physically smooth and sp3 dominated DLC film with tetrahedral coordination was prepared by plasma-enhanced chemical vapor deposition technique. The surface of the DLC film was exposed to hydrogen, oxygen and nitrogen plasma for physical and chemical modifications. The surface modification was based on the concept of adsorption-desorption of plasma species and surface entities of films. Energetic chemical species of microwave plasma are adsorbed, leading to desorbtion of the surface carbon atoms due to energy and momentum exchange. The interaction of such reactive species with DLC films enhanced the roughness, surface defects and dangling bonds of carbon atoms. Adsorbed hydrogen, oxygen and nitrogen formed a covalent network while saturating the dangling carbon bonds around the tetrahedral sp3 valency. The modified surface chemical affinity depends upon the charge carriers and electron covalency of the adsorbed atoms. The contact angle of chemically reconstructed surface increases when a water droplet interacts either through hydrogen or van dear Waals bonding. These weak interactions influenced the wetting property of the DLC surface to a great extent.

  7. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

    2016-01-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties. PMID:27363670

  8. Surface modification of materials by ion implantations for industrial and medical applications. Final report of a co-ordinated research project

    International Nuclear Information System (INIS)

    2000-07-01

    The objectives of the Co-ordinated Research Project on Modification of Materials by Ion Treatment for Industrial Applications were to develop economically acceptable surface modification techniques leading to thick treated layers, to predict ion beam mixing and impurity atom migration during and after implantation, and to evaluate the tribological post-implantation properties and performance of treated components. This TECDOC summarises the current status and prospects in surface modification by ion implantation methodology and technology, providing new information in basic and applied research

  9. Surface modification of materials by ion implantations for industrial and medical applications. Final report of a co-ordinated research project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The objectives of the Co-ordinated Research Project on Modification of Materials by Ion Treatment for Industrial Applications were to develop economically acceptable surface modification techniques leading to thick treated layers, to predict ion beam mixing and impurity atom migration during and after implantation, and to evaluate the tribological post-implantation properties and performance of treated components. This TECDOC summarises the current status and prospects in surface modification by ion implantation methodology and technology, providing new information in basic and applied research.

  10. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. (c) 2010 Wiley Periodicals, Inc.

  11. Effect of surface roughness and surface modification of indium tin oxide electrode on its potential response to tryptophan

    International Nuclear Information System (INIS)

    Khan, Md. Zaved Hossain; Nakanishi, Takuya; Kuroiwa, Shigeki; Hoshi, Yoichi; Osaka, Tetsuya

    2011-01-01

    Highlights: → We examine factors affecting potential response of ITO electrode to tryptophan. → Surface roughness of ITO electrode affects the stability of its rest potential. → Surface modification is effective for ITO electrode with a certain roughness. → Optimum values of work function exist for potential response of ITO to tryptophan. - Abstract: The effect of surface modification of indium tin oxide (ITO) electrode on its potential response to tryptophan was investigated for ITO substrates with different surface roughness. It was found that a small difference in surface roughness, between ∼1 and ∼2 nm of R a evaluated by atomic force microscopy, affects the rest potential of ITO electrode in the electrolyte. A slight difference in In:Sn ratio at the near surface of the ITO substrates, measured by angle-resolved X-ray photoelectron spectrometry and Auger electron spectroscopy is remarkable, and considered to relate with surface roughness. Interestingly, successive modification of the ITO surface with aminopropylsilane and disuccinimidyl suberate, of which essentiality to the potential response to indole compounds we previously reported, improved the stability of the rest potential and enabled the electrodes to respond to tryptophan in case of specimens with R a values ranging between ∼2 and ∼3 nm but not for those with R a of ∼1 nm. It was suggested that there are optimum values of effective work function of ITO for specific potential response to tryptophan, which can be obtained by the successive modification of ITO surface.

  12. Modification of inorganic surface with 1-alkenes and 1-alkynes

    NARCIS (Netherlands)

    Maat, ter J.

    2012-01-01

    Surface modification is important because it allows the tuning of surface properties, thereby enabling new applications of a material. It can change physical properties such as wettability and friction, but can also introduce chemical functionalities and binding specificity. Several techniques

  13. Silane surface modification for improved bioadhesion of esophageal stents

    Science.gov (United States)

    Karakoy, Mert; Gultepe, Evin; Pandey, Shivendra; Khashab, Mouen A.; Gracias, David H.

    2014-08-01

    Stent migration occurs in 10-40% of patients who undergo placement of esophageal stents, with higher migration rates seen in those treated for benign esophageal disorders. This remains a major drawback of esophageal stent therapy. In this paper, we propose a new surface modification method to increase the adhesion between self-expandable metallic stents (SEMS) and tissue while preserving their removability. Taking advantage of the well-known affinity between epoxide and amine terminated silane coupling agents with amine and carboxyl groups that are abundant in proteins and related molecules in the human body; we modified the surfaces of silicone coated esophageal SEMS with these adhesive self-assembled monolayers (SAMs). We utilized vapor phase silanization to modify the surfaces of different substrates including PDMS strips and SEMS, and measured the force required to slide these substrates on a tissue piece. Our results suggest that surface modification of esophageal SEMS via covalent attachment of protein-binding coupling agents improves adhesion to tissue and could offer a solution to reduce SEMS migration while preserving their removability.

  14. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    Science.gov (United States)

    Cho, Yong Ki; Park, Daewon; Kim, Hoonbae; Lee, Hyerim; Park, Heonyong; Kim, Hong Ja; Jung, Donggeun

    2014-03-01

    Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature-mimetic model systems, and to medical vascular grafts.

  15. Vapor phase modification of sol-gel derived titania (TiO{sub 2}) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Piwonski, Ireneusz [University of Lodz, Department of Chemical Technology and Environmental Protection, Pomorska 163, 90-236 Lodz (Poland)]. E-mail: irek@uni.lodz.pl; Ilik, Aneta [University of Lodz, Department of Chemical Technology and Environmental Protection, Pomorska 163, 90-236 Lodz (Poland)

    2006-12-30

    Chemical vapor deposition (CVD) method was used in titania surface modification. Titania layers were obtained in sol-gel process and prepared as thin films on silicon wafers in dip-coating method. In order to define the influence of modification on titania surface properties (e.g., friction), various types of fluoroalkylsilanes were used. The effectiveness of the modification was monitored by FT-IR spectroscopy. The topography and frictional measurements were investigated with the use of atomic force microscopy (AFM)

  16. Study of Textile Surface Characteristic Modification by Using Electron Beam Radiation

    International Nuclear Information System (INIS)

    Iswani Gitawati; Rany Saptaaji

    2007-01-01

    The success of accelerator technology application in various field of industry, medical and pharmacy, environment, agricultural, food increase each year as the increasing of people needs, not excepted for surface treatment of fibers and textiles in textile industry. This writing aim is to asses the application of electron beam accelerator for textile surface treatment on finishing step. Surface treatment was done with electron beam low energy (100 - 500 keV), and because of its low penetration it was suitable used to gain the improvement of chemical, physical and mechanical properties of textile surface such as adhesion, wettability, printability, dyes-intake, crease recovery, wrinkle-resistance, flammability, abrasion resistance, soil and stain release to get better result. Modification of fibers and textiles surface properties on finishing process can be caused by crosslinking, grafting and degradation reactions. The assesment results showed that the greatest impact on commercial application of radiation in textiles were crease recovery and surface modification of wetting properties (soil and stain release). The radiation dose used for those purposes were 5 - 50 kGy. The bach process of graft textiles surface modification before and after irradiation by Co-60 source (gamma energies of 1.33 and 1.17 MeV) and continue process by electron beam were presented. The assesment results were reported in this paper. (author)

  17. The third generation multi-purpose plasma immersion ion implanter for surface modification of materials

    CERN Document Server

    Tang Bao Yin; Wang Xiao Feng; Gan Kong Yin; Wang Song Yan; Chu, P K; Huang Nian Ning; Sun Hong

    2002-01-01

    The third generation multi-purpose plasma immersion ion implantation (PIII) equipment has been successfully used for research and development of surface modification of biomedical materials, metals and their alloys in the Southwest Jiaotong University. The implanter equipped with intense current, pulsed cathodic arc metal plasma sources which have both strong coating function and gas and metal ion implantation function. Its pulse high voltage power supply can provide big output current. It can acquire very good implantation dose uniformity. The equipment can both perform ion implantation and combine ion implantation with sputtering deposition and coating to form many kinds of synthetic surface modification techniques. The main design principles, features of important components and achievement of research works in recent time have been described

  18. Ion-Induced Surface Modification of Magnetically Operated Contacts

    Directory of Open Access Journals (Sweden)

    Karen Arushanov

    2012-02-01

    Full Text Available A study has been made of permalloy (iron-nickel contacts of reed switches before and after ion-induced surface modification using atomic force and optical microscopy, Auger electron and X-ray photoelectron spectroscopy. It has been found that the formation of surface nitride layers enhances corrosion and erosion resistance of contacts. We proposed to produce such layers directly into sealed reed switches by means of pulsing glow-discharge nitrogen plasma.

  19. Modeling nanostructural surface modifications in metal cutting by an approach of thermodynamic irreversibility: Derivation and experimental validation

    Science.gov (United States)

    Buchkremer, S.; Klocke, F.

    2017-01-01

    Performance and operational safety of many metal parts in engineering depend on their surface integrity. During metal cutting, large thermomechanical loads and high gradients of the loads concerning time and location act on the surfaces and may yield significant structural material modifications, which alter the surface integrity. In this work, the derivation and validation of a model of nanostructural surface modifications in metal cutting are presented. For the first time in process modeling, initiation and kinetics of these modifications are predicted using a thermodynamic potential, which considers the interdependent developments of plastic work, dissipation, heat conduction and interface energy as well as the associated productions and flows of entropy. The potential is expressed based on the free Helmholtz energy. The irreversible thermodynamic state changes in the workpiece surface are homogenized over the volume in order to bridge the gap between discrete phenomena involved with the initiation and kinetics of dynamic recrystallization and its macroscopic implications for surface integrity. The formulation of the thermodynamic potential is implemented into a finite element model of orthogonal cutting of steel AISI 4140. Close agreement is achieved between predicted nanostructures and those obtained in transmission electron microscopical investigations of specimen produced in cutting experiments.

  20. Plasma surface modification of rigid contact lenses decreases bacterial adhesion.

    Science.gov (United States)

    Wang, Yingming; Qian, Xuefeng; Zhang, Xiaofeng; Xia, Wei; Zhong, Lei; Sun, Zhengtai; Xia, Jing

    2013-11-01

    Contact lens safety is an important topic in clinical studies. Corneal infections usually occur because of the use of bacteria-carrying contact lenses. The current study investigated the impact of plasma surface modification on bacterial adherence to rigid contact lenses made of fluorosilicone acrylate materials. Boston XO and XO2 contact lenses were modified using plasma technology (XO-P and XO2-P groups). Untreated lenses were used as controls. Plasma-treated and control lenses were incubated in solutions containing Staphylococcus aureus or Pseudomonas aeruginosa. MTT colorimetry, colony-forming unit counting method, and scanning electron microscopy were used to measure bacterial adhesion. MTT colorimetry measurements showed that the optical density (OD) values of XO-P and XO2-P were significantly lower than those of XO and XO2, respectively, after incubation with S. aureus (P lenses and to the XO2-P versus XO2 lenses incubated with S. aureus (P lenses incubated with P. aeruginosa (P lenses. Plasma surface modification can significantly decrease bacterial adhesion to fluorosilicone acrylate contact lenses. This study provides important evidence of a unique benefit of plasma technology in contact lens surface modification.

  1. Effect of Reaction Conditions on the Surface Modification of Cellulose Nanofibrils with Aminopropyl Triethoxysilane

    Directory of Open Access Journals (Sweden)

    Eduardo Robles

    2018-04-01

    Full Text Available Nine different surface modifications of cellulose nanofibrils (CNF with 3-aminopropyl triethoxysilane (ATS by using three different solvent systems (water, ethanol, and a mixture of both were investigated. The effect of reaction conditions, such as silane to cellulose ratio and solvent type were evaluated to determine their contribution to the extent of the silane modification. Nanofibril properties were evaluated by infrared spectroscopy, powder X-ray diffraction, surface free energy, thermogravimetry, 13C and 29Si nuclear magnetic resonance, and electronic microscopy. The influence of the solvent in the solvolysis of the silane was reflected in the presence or absence of ethoxy groups in the silane. On the other hand, whereas the surface modification was increased directly proportionally to silane ratio on the reaction, the aggregation of nanofibrils was also increased, which can play a negative role in certain applications. The increment of silane modification also had substantial repercussions on the crystallinity of the nanofibrils by the addition of amorphous components to the crystalline unit; moreover, silane surface modifications enhanced the hydrophobic character of the nanofibrils.

  2. Ion beam modifications of near-surface compositions in ternary alloys

    International Nuclear Information System (INIS)

    Lam, N.Q.; Tang, S.; Yacout, A.M.; Rehn, L.E.; Stubbins, J.F.

    1990-11-01

    Changes in the surface and subsurface compositions of ternary alloys during elevated-temperature sputtering with inert-gas ions were investigated. Theoretically, a comprehensive kinetic model which includes all the basic processes, such as preferential sputtering, displacement mixing, Gibbsian segregation, radiation-enhanced diffusion and radiation-induced segregation, was developed. This phenomenological approach enabled to predict the effects of each individual process or of a combination of processes on the compositional modification in model alloys. Experimentally, measurements of compositional changes at the surface of a Ag-40at%Au -- 20at%Cu alloy during 3-keV Ne + bombardment at various temperatures were made, using ion scattering spectroscopy. These measurements were interpreted on the basis of the results of theoretical modeling. 8 refs., 2 figs

  3. Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media

    International Nuclear Information System (INIS)

    Kamiya, Hidehiro; Iijima, Motoyuki

    2010-01-01

    Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM). Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between nanoparticles and the effect of surface modification on the nanoparticle dispersion in liquids. (topical review)

  4. Surface modification and characterization for dispersion stability of inorganic nanometer-scaled particles in liquid media

    Directory of Open Access Journals (Sweden)

    Hidehiro Kamiya and Motoyuki Iijima

    2010-01-01

    Full Text Available Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM. Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between nanoparticles and the effect of surface modification on the nanoparticle dispersion in liquids.

  5. Green aqueous surface modification of polypropylene for novel polymer nanocomposites.

    Science.gov (United States)

    Thakur, Vijay Kumar; Vennerberg, Danny; Kessler, Michael R

    2014-06-25

    Polypropylene is one of the most widely used commercial commodity polymers; among many other applications, it is used for electronic and structural applications. Despite its commercial importance, the hydrophobic nature of polypropylene limits its successful application in some fields, in particular for the preparation of polymer nanocomposites. Here, a facile, plasma-assisted, biomimetic, environmentally friendly method was developed to enhance the interfacial interactions in polymer nanocomposites by modifying the surface of polypropylene. Plasma treated polypropylene was surface-modified with polydopamine (PDA) in an aqueous medium without employing other chemicals. The surface modification strategy used here was based on the easy self-polymerization and strong adhesion characteristics of dopamine (DA) under ambient laboratory conditions. The changes in surface characteristics of polypropylene were investigated using FTIR, TGA, and Raman spectroscopy. Subsequently, the surface modified polypropylene was used as the matrix to prepare SiO2-reinforced polymer nanocomposites. These nanocomposites demonstrated superior properties compared to nanocomposites prepared using pristine polypropylene. This simple, environmentally friendly, green method of modifying polypropylene indicated that polydopamine-functionalized polypropylene is a promising material for various high-performance applications.

  6. Topological surface states of Bi{sub 2}Te{sub 2}Se are robust against surface chemical modification

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Conor R.; Sahasrabudhe, Girija; Kushwaha, Satya Kumar; Cava, Robert J.; Schwartz, Jeffrey [Department of Chemistry, Princeton University, Princeton, NJ (United States); Xiong, Jun [Department of Physics, Princeton University, Princeton, NJ (United States)

    2014-12-01

    The robustness of the Dirac-like electronic states on the surfaces of topological insulators (TIs) during materials process-ing is a prerequisite for their eventual device application. Here, the (001) cleavage surfaces of crystals of the topological insulator Bi{sub 2}Te{sub 2}Se (BTS) were subjected to several surface chemical modification procedures that are common for electronic materials. Through measurement of Shubnikov-de Hass (SdH) oscillations, which are the most sensitive measure of their quality, the surface states of the treated surfaces were compared to those of pristine BTS that had been exposed to ambient conditions. In each case - surface oxidation, deposition of thin layers of Ti or Zr oxides, or chemical modification of the surface oxides - the robustness of the topological surface electronic states was demonstrated by noting only very small changes in the frequency and amplitude of the SdH oscillations. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Work function modifications of graphite surface via oxygen plasma treatment

    Science.gov (United States)

    Duch, J.; Kubisiak, P.; Adolfsson, K. H.; Hakkarainen, M.; Golda-Cepa, M.; Kotarba, A.

    2017-10-01

    The surface modification of graphite by oxygen plasma was investigated experimentally (X-ray diffraction, nanoparticle tracking analysis, laser desorption ionization mass spectrometry, thermogravimetry, water contact angle) and by molecular modelling (Density Functional Theory). Generation of surface functional groups (mainly sbnd OHsurf) leads to substantial changes in electrodonor properties and wettability gauged by work function and water contact angle, respectively. The invoked modifications were analyzed in terms of Helmholtz model taking into account the theoretically determined surface dipole moment of graphite-OHsurf system (μ = 2.71 D) and experimentally measured work function increase (from 0.75 to 1.02 eV) to determine the sbnd OH surface coverage (from 0.70 to 1.03 × 1014 groups cm-2). Since the plasma treatment was confined to the surface, the high thermal stability of the graphite material was preserved as revealed by the thermogravimetric analysis. The obtained results provide a suitable quantitative background for tuning the key operating parameters of carbon electrodes: electronic properties, interaction with water and thermal stability.

  8. Ultralow energy ion beam surface modification of low density polyethylene.

    Science.gov (United States)

    Shenton, Martyn J; Bradley, James W; van den Berg, Jaap A; Armour, David G; Stevens, Gary C

    2005-12-01

    Ultralow energy Ar+ and O+ ion beam irradiation of low density polyethylene has been carried out under controlled dose and monoenergetic conditions. XPS of Ar+-treated surfaces exposed to ambient atmosphere show that the bombardment of 50 eV Ar+ ions at a total dose of 10(16) cm(-2) gives rise to very reactive surfaces with oxygen incorporation at about 50% of the species present in the upper surface layer. Using pure O+ beam irradiation, comparatively low O incorporation is achieved without exposure to atmosphere (approximately 13% O in the upper surface). However, if the surface is activated by Ar+ pretreatment, then large oxygen contents can be achieved under subsequent O+ irradiation (up to 48% O). The results show that for very low energy (20 eV) oxygen ions there is a dose threshold of about 5 x 10(15) cm(-2) before surface oxygen incorporation is observed. It appears that, for both Ar+ and O+ ions in this regime, the degree of surface modification is only very weakly dependent on the ion energy. The results suggest that in the nonequilibrium plasma treatment of polymers, where the ion flux is typically 10(18) m(-2) s(-1), low energy ions (<50 eV) may be responsible for surface chemical modification.

  9. Methodological guidelines for developing accident modification functions

    DEFF Research Database (Denmark)

    Elvik, Rune

    2015-01-01

    This paper proposes methodological guidelines for developing accident modification functions. An accident modification function is a mathematical function describing systematic variation in the effects of road safety measures. The paper describes ten guidelines. An example is given of how to use...... limitations in developing accident modification functions are the small number of good evaluation studies and the often huge variation in estimates of effect. It is therefore still not possible to develop accident modification functions for very many road safety measures. © 2015 Elsevier Ltd. All rights...... the guidelines. The importance of exploratory analysis and an iterative approach in developing accident modification functions is stressed. The example shows that strict compliance with all the guidelines may be difficult, but represents a level of stringency that should be strived for. Currently the main...

  10. Surface Modification of Poly(tetrafluoroethylene) by Magnesium Amalgam

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Janda, Pavel; Weber, Jan

    2001-01-01

    Roč. 36, - (2001), s. 879-885 ISSN 0022-2461 R&D Projects: GA ČR GA203/98/1168; GA ČR GA203/98/1181 Institutional research plan: CEZ:AV0Z4040901 Keywords : poly(tetrafluoroethylene) * surface modification * ESCA Subject RIV: CG - Electrochemistry Impact factor: 0.728, year: 2001

  11. Surface modification of steels and magnesium alloy by high current pulsed electron beam

    Science.gov (United States)

    Hao, Shengzhi; Gao, Bo; Wu, Aimin; Zou, Jianxin; Qin, Ying; Dong, Chuang; An, Jian; Guan, Qingfeng

    2005-11-01

    High current pulsed electron beam (HCPEB) is now developing as a useful tool for surface modification of materials. When concentrated electron flux transferring its energy into a very thin surface layer within a short pulse time, superfast processes such as heating, melting, evaporation and consequent solidification, as well as dynamic stress induced may impart the surface layer with improved physico-chemical and mechanical properties. This paper presents our research work on surface modification of steels and magnesium alloy with HCPEB of working parameters as electron energy 27 keV, pulse duration ∼1 μs and energy density ∼2.2 J/cm2 per pulse. Investigations performed on carbon steel T8, mold steel D2 and magnesium alloy AZ91HP have shown that the most pronounced changes of phase-structure state and properties occurring in the near-surface layers, while the thickness of the modified layer with improved microhardness (several hundreds of micrometers) is significantly greater than that of the heat-affected zone. The formation mechanisms of surface cratering and non-stationary hardening effect in depth are discussed based on the elucidation of non-equilibrium temperature filed and different kinds of stresses formed during pulsed electron beam melting treatment. After the pulsed electron beam treatments, samples show significant improvements in measurements of wear and corrosion resistance.

  12. Surface modification of steels and magnesium alloy by high current pulsed electron beam

    International Nuclear Information System (INIS)

    Hao, Shengzhi; Gao, Bo; Wu, Aimin; Zou, Jianxin; Qin, Ying; Dong, Chuang; An, Jian; Guan, Qingfeng

    2005-01-01

    High current pulsed electron beam (HCPEB) is now developing as a useful tool for surface modification of materials. When concentrated electron flux transferring its energy into a very thin surface layer within a short pulse time, superfast processes such as heating, melting, evaporation and consequent solidification, as well as dynamic stress induced may impart the surface layer with improved physico-chemical and mechanical properties. This paper presents our research work on surface modification of steels and magnesium alloy with HCPEB of working parameters as electron energy 27 keV, pulse duration ∼1 μs and energy density ∼2.2 J/cm 2 per pulse. Investigations performed on carbon steel T8, mold steel D2 and magnesium alloy AZ91HP have shown that the most pronounced changes of phase-structure state and properties occurring in the near-surface layers, while the thickness of the modified layer with improved microhardness (several hundreds of micrometers) is significantly greater than that of the heat-affected zone. The formation mechanisms of surface cratering and non-stationary hardening effect in depth are discussed based on the elucidation of non-equilibrium temperature filed and different kinds of stresses formed during pulsed electron beam melting treatment. After the pulsed electron beam treatments, samples show significant improvements in measurements of wear and corrosion resistance

  13. Modification of polymer surfaces to enhance enzyme activity and stability

    DEFF Research Database (Denmark)

    Hoffmann, Christian

    Enzyme immobilization is an important concept for the development of improved biocatalytic processes, primarily through facilitated separation procedures. However, enzyme immobilization usually comes at a price of reduced biocatalytic activity. For this reason, different immobilization methods have...... already been developed, combining the same goal to improve enzyme activity, stability and selectivity. Polymer materials have shown, due to their easy processibility and versatile properties, high potential as enzyme support. However, in order to achieve improved enzyme performance, the combination...... on their tailored surface modification in order to obtain improved enzyme-support systems. Firstly, an off-stoichiometric thiol-ene (OSTE) thermosetting material was used for the development of a screening platform allowing the investigation of micro-environmental effects and their impact on the activity...

  14. Surface modification of metals by ion implantation

    International Nuclear Information System (INIS)

    Iwaki, Masaya

    1988-01-01

    Ion implantation in metals has attracted the attention as a useful technology for the formation of new metastable alloys and compounds in metal surface layers without thermal equilibrium. Current studies of metal surface modification by ion implantation with high fluences have expanded from basic research areas and to industrial applications for the improvement of life time of tools. Many results suggest that the high fluence implantation produces the new surface layers with un-expected microscopic characteristics and macroscopic properties due to implant particles, radiation damage, sputtering, and knock-on doping. In this report, the composition, structure and chemical bonding state in surface layers of iron, iron-based alloy and aluminum sheets implanted with high fluences have been investigated by means of secondary ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Tribological properties such as hardness, friction and wear are introduced. (author)

  15. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Singh, Shailendra Vikram; Norrman, Kion

    and the material surface, and thus many reactive species generated in the plasma can reach the surface before inactivated, and be efficiently utilized for surface modification. In the present work polyester plates are treated using a dielectric barrier discharge (DBD) and a gliding arc at atmospheric pressure......Atmospheric pressure plasma treatment can be highly enhanced by simultaneous high-power ultrasonic irradiation onto the treating surface. It is because ultrasonic waves with a sound pressure level (SPL) above approximately 140 dB can reduce the thickness of a boundary gas layer between the plasma...... irradiation, the water contact angle dropped markedly, and tended to decrease furthermore at higher power. The ultrasonic irradiation during the plasma treatment consistently improved the wettability. Oxygen containing polar functional groups were introduced at the surface by the plasma treatment...

  16. Surface modification of polyethylene by plasma

    International Nuclear Information System (INIS)

    Colin O, E.

    2003-01-01

    The products made of polyethylene (PE) go from construction materials, electric insulating until packing material. The films for bags and pack occupy 83.6% of the distribution of the market of PE approximately. The enormous quantity of PE that is generated by its indiscriminate use brings as consequence a deterioration to the atmosphere, due to the long life that they present as waste. This work is a study on the modification of low density polyethylene films. In this type of thin materials, the changes in the surface meet with largely on the conformation of the rest of the material. To induce changes that modify the surface of PE, plasmas were used with reactive atmospheres of air, oxygen and nitrogen. The experimentation that was carries out went to introduce the PE to a cylindrical reactor where it was generated the plasma of air, oxygen and nitrogen to different times of exposure. After having carried out the exposure to the plasma, it was found that in the polyethylene it modifies their morphology, crystallinity, hydrophobicity, composition and electric conductivity. The analytical techniques that were used to characterize later to the polyethylene of being in contact with the plasma were: X-ray diffraction, Scanning Electron Microscopy, Infrared spectroscopy, Electric conductivity, Angle of contact and finally Thermal Gravimetric Analysis. The content of this work it is presented in five chapters: In the chapter 1 there are presented some general concepts of plasma and of the one polymer in study PE. In the chapter 2 it is made a general revision on modification of surfaces, as well as the properties that were modified in polymeric materials that were exposed to plasma in previous works. In the chapter 3 the experimental part and the conditions used are described in the modification of the PE. Also in this chapter a brief description it is made of the used characterization techniques. The results and discussion are presented in the chapter 4. These results

  17. Surface modification of malachite with ethanediamine and its effect on sulfidization flotation

    Science.gov (United States)

    Feng, Qicheng; Zhao, Wenjuan; Wen, Shuming

    2018-04-01

    Ethanediamine was used to modify the mineral surface of malachite to improve its sulfidization and flotation behavior. The activation mechanism was investigated by adsorption experiments, X-ray photoelectron spectroscopy (XPS) analysis, and zeta potential measurements. Microflotation experiments showed that the flotation recovery of malachite was enhanced after the pretreatment of the mineral particles with ethanediamine prior to the addition of Na2S. Adsorption tests revealed that numerous sulfide ion species in the pulp solution were transferred onto the mineral surface through the formation of more copper sulfide species. This finding was confirmed by the results of the XPS measurements. Ethanediamine modification not only increased the contents of copper sulfide species on the malachite surface but also enhanced the reactivity of the sulfidization products. During sulfidization, Cu(II) species on the mineral surface were reduced into Cu(I) species, and the percentages of S22- and Sn2- relative to the total S increased after modification, resulting in increased surface hydrophobicity. The results of zeta potential measurements showed that the ethanediamine-modified mineral surface adsorbed with more sulfide ion species was advantageous to the attachment of xanthate species, thereby improving malachite floatability. The proposed ethanediamine modification followed by sulfidization xanthate flotation exhibits potential for industrial application.

  18. Use of modern methods of fibre surface modification to obtain the multifunctional properties of textile materials

    Directory of Open Access Journals (Sweden)

    Jocić Dragan

    2003-01-01

    Full Text Available The modern textile fibre treatments aim to obtain the required level of beneficial effect while attempting to confine the modification to the fibre surface. Recently, much attention has been focused on different physical methods of fibre surface modification, cold plasma treatment being considered as very useful. Moreover, there are efficient chemical methods available, such as peroxide, biopolymer and enzyme treatment. Some interesting combinations of these physical and chemical surface modification methods as means to modify fibre surface topography and thus controlling the surface-related properties of the fibre are presented in this paper. The properties obtained are discussed on the basis of the physico-chemical changes in the surface layer of the fibre, being assessed by wettability and contact angle measurements, as well as by FTIR-ATR and XPS analysis. The SEM and AFM technique are used to assess the changes in the fibre surface topography and to correlate these changes to the effectiveness, uniformity and severity of the textile fibre surface modification treatments.

  19. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    International Nuclear Information System (INIS)

    To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

    2015-01-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

  20. Benefits of aggregates surface modification in concrete production

    Science.gov (United States)

    Junak, J.; Sicakova, A.

    2017-10-01

    In our study, recycled concrete aggregates (RCA), which surfaces had been modified by geopolymer material based on coal fly ash, were used to produce the concrete samples. In these samples, fraction 4/8 mm was replaced by recycled concrete aggregate with a range of 100%. To modify the surface of RCA was “Solo” and “Triple stage” modification used. On these samples real density, total water absorption and compressive strength were examined after 28, 90, 180 and 365 days of hardening. The highest compressive strength 56.8 MPa, after 365 days hardening, reached sample which had improved RCA surface by “Triple stage mixing”.

  1. Surface modification of GC and HOPG with diazonium, amine, azide, and olefin derivatives.

    Science.gov (United States)

    Tanaka, Mutsuo; Sawaguchi, Takahiro; Sato, Yukari; Yoshioka, Kyoko; Niwa, Osamu

    2011-01-04

    Surface modification of glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) was carried out with diazonium, amine, azide, and olefin derivatives bearing ferrocene as an electroactive moiety. Features of the modified surfaces were evaluated by surface concentrations of immobilized molecule, blocking effect of the modified surface against redox reaction, and surface observation using cyclic voltammetry and electrochemical scanning tunneling microscope (EC-STM). The measurement of surface concentrations of immobilized molecule revealed the following three aspects: (i) Diazonium and olefin derivatives could modify substrates with the dense-monolayer concentration. (ii) The surface concentration of immobilized amine derivative did not reach to the dense-monolayer concentration reflecting their low reactivity. (iii) The surface modification with the dense-monolayer concentration was also possible with azide derivative, but the modified surface contained some oligomers produced by the photoreaction of azides. Besides, the blocking effect against redox reaction was observed for GC modified with diazonium derivative and for HOPG modified with diazonium and azide derivatives, suggesting fabrication of a densely modified surface. Finally, the surface observation for HOPG modified with diazonium derivative by EC-STM showed a typical monolayer structure, in which the ferrocene moieties were packed densely at random. On the basis of those results, it was demonstrated that surface modification of carbon substrates with diazonium could afford a dense monolayer similar to the self-assembled monolayer (SAM) formation.

  2. Effect of surface modification on carbon fiber and its reinforced phenolic matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Hua [Key Laboratory for Liquid phase chemical oxidation Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Carbon Fibre Engineering Research Center, Faculty of Materials Science, Shandong University, Jinan 250061 (China); Wang Chengguo, E-mail: sduwangchg@gmail.com [Carbon Fibre Engineering Research Center, Faculty of Materials Science, Shandong University, Jinan 250061 (China); Zhang Shan; Lin Xue [Carbon Fibre Engineering Research Center, Faculty of Materials Science, Shandong University, Jinan 250061 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We used very simple and effective modification method to treat PAN-based carbon fiber by liquid oxidation and coupling agent. Black-Right-Pointing-Pointer Carbon fiber surface functional groups were analyzed by LRS and XPS. Black-Right-Pointing-Pointer Proper treatment of carbon fiber can prove an effective way to increase composite's performance. Black-Right-Pointing-Pointer Carbon fiber surface modifications by oxidation and APS could strengthen fiber activity and enlarge surface area as well as its roughness. - Abstract: In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H{sub 2}SO{sub 4}, KClO{sub 3} and silane coupling agent ({gamma}-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make C-O-R content increase and O-C=O content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor

  3. Effect of surface modification on carbon fiber and its reinforced phenolic matrix composite

    International Nuclear Information System (INIS)

    Yuan Hua; Wang Chengguo; Zhang Shan; Lin Xue

    2012-01-01

    Highlights: ► We used very simple and effective modification method to treat PAN-based carbon fiber by liquid oxidation and coupling agent. ► Carbon fiber surface functional groups were analyzed by LRS and XPS. ► Proper treatment of carbon fiber can prove an effective way to increase composite's performance. ► Carbon fiber surface modifications by oxidation and APS could strengthen fiber activity and enlarge surface area as well as its roughness. - Abstract: In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H 2 SO 4 , KClO 3 and silane coupling agent (γ-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make C-O-R content increase and O-C=O content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor performance of the resulting fiber/resin composites.

  4. Surface modification of fluorocarbon polymers by synchrotron radiation

    CERN Document Server

    Kanda, K; Matsui, S; Ideta, T; Ishigaki, H

    2003-01-01

    The surface modification of a poly (tetrafluoroethylene) sheet was carried out by synchrotron radiation in the soft X-ray region. The poly (tetrafluoroethylene) substrate was exposed to synchrotron radiation while varying the substrate temperature from room temperature to 200degC. The contact angle of the modified surfaces with a water drop decreased from 96deg to 72deg by the irradiation at room temperature, while the contact angle increased to 143deg by the irradiation at the substrate temperature of 200degC. Scanning electron microscopy suggested that this repellence was ascribable to the microstructure of the poly (tetrafluoroethylene) surface. We succeeded in controlling the wettability of the poly (tetrafluoroethylene) surface from hydrophobic to hydrophilic by irradiation of the soft X-ray light. (author)

  5. Plasma-implantation-based surface modification of metals with single-implantation mode

    Science.gov (United States)

    Tian, X. B.; Cui, J. T.; Yang, S. Q.; Fu, Ricky K. Y.; Chu, Paul K.

    2004-12-01

    Plasma ion implantation has proven to be an effective surface modification technique. Its biggest advantage is the capability to treat the objects with irregular shapes without complex manipulation of target holder. Many metal materials such as aluminum, stainless steel, tool steel, titanium, magnesium etc, has been treated using this technique to improve their wear-resistance, corrosion-resistance, fatigue-resistance, oxidation-resistance, bio-compatiblity etc. However in order to achieve thicker modified layers, hybrid processes combining plasma ion implantation with other techniques have been frequently employed. In this paper plasma implantation based surface modification of metals using single-implantation mode is reviewed.

  6. Fast surface modification by microwave assisted click reactions on silicon substrates

    NARCIS (Netherlands)

    Haensch, C.; Erdmenger, T.; Fijten, M.W.M.; Höppener, S.; Schubert, U.S.

    2009-01-01

    Microwave irradiation has been used for the chemical modification of functional monolayers on silicon surfaces. The thermal and chemical stability of these layers was tested under microwave irradiation to investigate the possibility to use this alternative heating process for the surface

  7. Laser surface modification of boronickelized medium carbon steel

    Science.gov (United States)

    Bartkowska, Aneta; Pertek, Aleksandra; Kulka, Michał; Klimek, Leszek

    2015-11-01

    A two-step process was applied to produce the multicomponent boride layers. Boronickelizing consisted of nickel plating and diffusion boriding. Two different methods of heat treatment of boronickelized C45 steel were used: a typical through-hardening, and a laser surface modification with remelting. Microstructure and some mechanical properties of these layers were examined. Microstructural characterization was studied using optical microscope, Scanning Electron Microscope, energy-dispersive X-ray microanalysis, Electron Back-Scatter Diffraction and X-ray diffraction. The laser modification improved wear resistance, cohesion as well as low-cycle fatigue of the boronickelized layer. Compressive stresses, occurring after laser remelting, could be the reason for the advantageous mechanical behavior of the layer.

  8. Surface charging, discharging and chemical modification at a sliding contact

    DEFF Research Database (Denmark)

    Singh, Shailendra Vikram; Kusano, Yukihiro; Morgen, Per

    2012-01-01

    Electrostatic charging, discharging, and consequent surface modification induced by sliding dissimilar surfaces have been studied. The surface-charge related phenomena were monitored by using a home-built capacitive, non-contact electrical probe, and the surface chemistry was studied by X...... are also able to comment on the behavior and the charge decay time in the ambient air-like condition, once the sliding contact is discontinued. XPS analysis showed a marginal deoxidation effect on the polyester disks due to the charging and discharging of the surfaces. Moreover, these XPS results clearly...

  9. The effects of size and surface modification of amorphous silica particles on biodistribution and liver metabolism in mice

    Science.gov (United States)

    Lu, Xiaoyan; Ji, Cai; Jin, Tingting; Fan, Xiaohui

    2015-05-01

    Engineered nanoparticles, with unconventional properties, are promising platforms for biomedical applications. Since they may interact with a wide variety of biomolecules, it is critical to understand the impact of the physicochemical properties of engineered nanoparticles on biological systems. In this study, the effects of particle size and surface modification alone or in combination of amorphous silica particles (SPs) on biological responses were determined using a suite of general toxicological assessments and metabonomics analysis in mice model. Our results suggested that amino or carboxyl surface modification mitigated the liver toxicity of plain-surface SPs. 30 nm SPs with amino surface modification were found to be the most toxic SPs among all the surface-modified SP treatments at the same dosage. When treatment dose was increased, submicro-sized SPs with amino or carboxyl surface modification also induced liver toxicity. Biodistribution studies suggested that 70 nm SPs were mainly accumulated in liver and spleen regardless of surface modifications. Interestingly, these two organs exhibited different uptake trends. Furthermore, metabonomics studies indicated that surface modification plays a more dominant role to affect the liver metabolism than particle size.

  10. Long-term drug modification to the surface of mesenchymal stem cells by the avidin-biotin complex method.

    Science.gov (United States)

    Takayama, Yukiya; Kusamori, Kosuke; Hayashi, Mika; Tanabe, Noriko; Matsuura, Satoru; Tsujimura, Mari; Katsumi, Hidemasa; Sakane, Toshiyasu; Nishikawa, Makiya; Yamamoto, Akira

    2017-12-05

    Mesenchymal stem cells (MSCs) have various functions, making a significant contribution to tissue repair. On the other hand, the viability and function of MSCs are not lasting after an in vivo transplant, and the therapeutic effects of MSCs are limited. Although various chemical modification methods have been applied to MSCs to improve their viability and function, most of conventional drug modification methods are short-term and unstable and cause cytotoxicity. In this study, we developed a method for long-term drug modification to C3H10T1/2 cells, murine mesenchymal stem cells, without any damage, using the avidin-biotin complex method (ABC method). The modification of NanoLuc luciferase (Nluc), a reporter protein, to C3H10T1/2 cells by the ABC method lasted for at least 14 days in vitro without major effects on the cellular characteristics (cell viability, cell proliferation, migration ability, and differentiation ability). Moreover, in vivo, the surface Nluc modification to C3H10T1/2 cells by the ABC method lasted for at least 7 days. Therefore, these results indicate that the ABC method may be useful for long-term surface modification of drugs and for effective MSC-based therapy.

  11. Effects of combinative surface modification on the stability and conductivity of the copper particles

    International Nuclear Information System (INIS)

    Zeng, Yike; Li, Tongtong; Fu, Ming; Jiang, Shenglin; Zhang, Guangzu

    2014-01-01

    Highlights: • A combinative method is used to improve the performance of the copper powder. • The method integrates passivation, silver-coating, and coupling agent treatment. • The stability of the copper powder has been improved after the modification. • The sheet resistance of the conductive film is reduced to 15 mΩ. -- Abstract: The specific goal of the present study is to evaluate the surface performance of the copper particles and get excellent copper powder by surface modification. This paper proposes a combinative modification method integrating passivation, silver-coated, and coupling agent. As a result, after 600 h at room temperature the copper powder has the stabilization improved and is well combined with organic matters, and the sheet resistance of the film fabricated by the copper conductive filler is reduced to 15 mΩ. The performance of the copper powder has been greatly enhanced by the combinative modification, and the cost of the copper conductive filler is decreased significantly by this method. The results indicate that the combinative surface modification method can be used for practical electronic application

  12. Application of xenon difluoride for surface modification of polymers

    International Nuclear Information System (INIS)

    Barsamyan, G.B.; Belokonov, K.V.; Vargasova, N.A.; Sokolov, V.B.; Chaivanov, B.B.; Zubov, V.P.

    1994-01-01

    Chemical interaction between xenon difluoride (XeF 2 ) and polymeric materials was investigated. It was shown that the reaction occurs on the surface of solid polymer layer and brings to chemical modification of the surface properties of the polymer leaving the bulk properties unchanged. The results of various analysis of the fluorinated samples (IR, FTIR-ATR, ESCA, bulk analysis etc) are presented. The mechanism of reaction is proposed. 12 refs.; 13 figs

  13. Hydrophilic Surface Modification of PDMS Microchannel for O/W and W/O/W Emulsions

    Directory of Open Access Journals (Sweden)

    Shazia Bashir

    2015-09-01

    Full Text Available A surface modification method for bonded polydimethylsiloxane (PDMS microchannels is presented herein. Polymerization of acrylic acid was performed on the surface of a microchannel using an inline atmospheric pressure dielectric barrier microplasma technique. The surface treatment changes the wettability of the microchannel from hydrophobic to hydrophilic. This is a challenging task due to the fast hydrophobic recovery of the PDMS surface after modification. This modification allows the formation of highly monodisperse oil-in-water (O/W droplets. The generation of water-in-oil-in-water (W/O/W double emulsions was successfully achieved by connecting in series a hydrophobic microchip with a modified hydrophilic microchip. An original channel blocking technique to pattern the surface wettability of a specific section of a microchip using a viscous liquid comprising a mixture of honey and glycerol, is also presented for generating W/O/W emulsions on a single chip.

  14. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    International Nuclear Information System (INIS)

    Bai Liqiang; Zhu Liangjun; Min Sijia; Liu Lin; Cai Yurong; Yao Juming

    2008-01-01

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH 2 )-NGIVKAGPAIAVLGEAAL-CONH 2 , using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

  15. Surface modification and properties of Bombyx mori silk fibroin films by antimicrobial peptide

    Energy Technology Data Exchange (ETDEWEB)

    Bai Liqiang [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Zhu Liangjun; Min Sijia [College of Animal Sciences, Zhejiang University, Hangzhou 310029 (China); Liu Lin; Cai Yurong [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China); Yao Juming [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Park, Hangzhou 310018 (China)], E-mail: yaoj@zstu.edu.cn

    2008-03-15

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH{sub 2})-NGIVKAGPAIAVLGEAAL-CONH{sub 2}, using the carbodiimide chemistry method. In order to avoid the dissolution of films during the modification procedure, the SFFs were first treated with 60% (v/v) ethanol aqueous solution, resulting a structural transition from unstable silk I to silk II. The investigation of modification conditions showed that the surface-modified SFFs had the satisfied antimicrobial activity and durability when they were activated by EDC.HCl/NHS solution followed by a treatment in CB peptide/PBS buffer (pH 6.5 or 8) solution at ambient temperature for 2 h. Moreover, the surface-modified SFFs showed the smaller contact angle due to the hydrophilic antimicrobial peptides coupled on the film surface, which is essential for the cell adhesion and proliferation. AFM results indicated that the surface roughness of SFFs was considerably increased after the modification by the peptides. The elemental composition analysis results also suggested that the peptides were tightly coupled to the surface of SFFs. This approach may provide a new option to engineer the surface-modified implanted materials preventing the biomaterial-centered infection (BCI)

  16. Surface modification of promising cerium oxide nanoparticles for nanomedicine applications

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-11-14

    Cerium oxide nanoparticles (CNPs) or nanoceria have emerged as a potential nanomedicine for the treatment of several diseases such as cancer. CNPs have a natural tendency to aggregate or agglomerate in their bare state, which leads to sedimentation in a biological environment. Since the natural biological environment is essentially aqueous, nanoparticle surface modification using suitable biocompatible hydrophilic chemical moieties is highly desirable to create effective aqueous dispersions. In this report, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)triethoxysilane was used as a functional, biocompatible organosilane to modify the surface of CNPs to produce promising nanoparticles which open substantial therapeutic avenues. The surface modified nanoparticles were produced in situ via an ammonia-induced ethylene glycol-assisted precipitation method and were characterized using complimentary characterization techniques. The interaction between the functional moiety and the nanoparticle was studied using powerful cross polarization/magic angle sample spinning solid state nuclear magnetic resonance spectroscopy. The surface-modified nanoparticles were extremely small and demonstrated a significant improvement in aqueous dispersibility. Moreover, the existence of a strong ionic coordination between the functional moiety and the surface of the nanoparticle was realised, indicating that the surface modified nanoceria are stable and that the nanoparticles should demonstrate an enhanced circulation time in a biological environment. The surface modification approach should be promising for the production of CNPs for nanomedicine applications. © The Royal Society of Chemistry.

  17. Pore channel surface modification for enhancing anti-fouling membrane distillation

    Science.gov (United States)

    Qiu, Haoran; Peng, Yuelian; Ge, Lei; Villacorta Hernandez, Byron; Zhu, Zhonghua

    2018-06-01

    Membrane surface modification by forming a functional layer is an effective way to improve the anti-fouling properties of membranes; however, the additional layer and the potential blockage of bulk pores may increase the mass transfer resistance and reduce the permeability. In this study, we applied a novel method of preparing anti-fouling membranes for membrane distillation by dispersing graphene oxide (GO) on the channel surface of polyvinylidene fluoride membranes. The surface morphology and properties were characterized by scanning electron microscopy, atomic force microscope, and Fourier transform infrared spectrometry. Compared to the membrane surface modification by nanoparticles (e.g. SiO2), GO was mainly located on the pore surface of the membrane bulk, rather than being formed as an individual layer onto the membrane surface. The performance was evaluated via a direct-contact membrane distillation process with anionic and cationic surfactants as the foulants, separately. Compared to the pristine PVDF membrane, the anti-fouling behavior and distillate flux of the GO-modified membranes were improved, especially when using the anionic surfactant as the foulant. The enhanced anti-fouling performance can be attributed to the oxygen containing functional groups in GO and the healing of the membrane pore defects. This method may provide an effective route to manipulate membrane pore surface properties for anti-fouling separation without increasing mass transfer resistance.

  18. In-situ investigation of laser surface modifications of WC-Co hard metals inside a scanning electron microscope

    Science.gov (United States)

    Mueller, H.; Wetzig, K.; Schultrich, B.; Pompe, Wolfgang; Chapliev, N. I.; Konov, Vitaly I.; Pimenov, S. M.; Prokhorov, Alexander M.

    1989-05-01

    The investigation of laser interaction with solid surfaces and of the resulting mechanism of surface modification are of technical interest to optimize technological processes, and they are also of fundamental scientific importance. Most instructive indormation is available with the ail of the in-situ techniques. For instance, measuring of the photon emission of the irradiated surface ane the plasma torch (if it is produced) simultaneously to laser action, makes it possible to gain a global characterization of the laser-solid interaction. In order to obtain additional information about surface and structure modifications in microscopic detail , a laser and scanning electron microscope were combined in to a tandem equipment (LASEM). Inside this eqiipment the microscopic observation is carried out directly at the laser irradiated area without any displacement of the sample. In this way, the stepwise development of surface modification during multipulse irradiation is visible in microscopic details and much more reliable information about the surface modification process is obtainable in comparison to an external laser irradiation. Such kind of equipments were realized simultaneously and independently in the Institut of General Physics (Moscow) and the Central Institute of Solid State Physics and Material Research (Dresden) using a CO2 and a LTd-glass-laser, respectively. In the following the advantages and possibilities of a LASEM shall be demonstrated by some selected investigations of WC-CO hardmeta. The results were obtained in collaboration by both groups with the aid of the pulsed CO2-laser. The TEA CO2 laser was transmitted through a ZnSe-window into the sample chamber of the SEM and focused ofAo tfte sample surface. It was operated in TEM - oo mode with a repetition rate of about 1 pulse per second. A peak power density of about 160 MW/cm2 was achieved in front of the sample surface.

  19. A study of laser surface modification of polymers: A comparison in air and water

    DEFF Research Database (Denmark)

    Marla, Deepak; Andersen, Sebastian A.; Zhang, Yang

    2018-01-01

    Laser surface modification is a technique to modify polymer surfaces for various applications. In our earlier work [Physics Procedia, 83:211–217, 2016], we showed that when the laser surface modification process was carried out in water instead of air, the obtained surface characteristics were...... research. The observed images of laser modified surfaces suggest that a hemispherical hump is formed in the case of water at lower laser fluences that breakup with an increase in fluence. Such a behavior was not observed when the process was carried out in air. We explain this phenomenon by simulating...

  20. Surface modifications of dental implants.

    Science.gov (United States)

    Stanford, C M

    2008-06-01

    Dental implant surface technologies have been evolving rapidly to enhance a more rapid bone formation on their surface and hold a potential to increase the predictability of expedited implant therapy. While implant outcomes have become highly predictable, there are sites and conditions that result in elevated implant loss. This paper reviews the impact of macro-retentive features which includes approaches to surface oxide modification, thread design, press-fit and sintered-bead technologies to increase predictability of outcomes. Implant designs that lead to controlled lateral compression of the bone can improve primary stability as long as the stress does not exceed the localized yield strength of the cortical bone. Some implant designs have reduced crestal bone loss by use of multiple cutting threads that are closely spaced, smoothed on the tip but designed to create a hoop-stress stability of the implant as it is completely seated in the osteotomy. Following the placement of the implant, there is a predictable sequence of bone turnover and replacement at the interface that allows the newly formed bone to adapt to microscopic roughness on the implant surface, and on some surfaces, a nanotopography (<10(-9) m scale) that has been shown to preferably influence the formation of bone. Newly emerging studies show that bone cells are exquisitely sensitive to these topographical features and will upregulate the expression of bone related genes for new bone formation when grown on these surfaces. We live in an exciting time of rapid changes in the modalities we can offer patients for tooth replacement therapy. Given this, it is our responsibility to be critical when claims are made, incorporate into our practice what is proven and worthwhile, and to continue to support and provide the best patient care possible.

  1. Boiling and quenching heat transfer advancement by nanoscale surface modification.

    Science.gov (United States)

    Hu, Hong; Xu, Cheng; Zhao, Yang; Ziegler, Kirk J; Chung, J N

    2017-07-21

    All power production, refrigeration, and advanced electronic systems depend on efficient heat transfer mechanisms for achieving high power density and best system efficiency. Breakthrough advancement in boiling and quenching phase-change heat transfer processes by nanoscale surface texturing can lead to higher energy transfer efficiencies, substantial energy savings, and global reduction in greenhouse gas emissions. This paper reports breakthrough advancements on both fronts of boiling and quenching. The critical heat flux (CHF) in boiling and the Leidenfrost point temperature (LPT) in quenching are the bottlenecks to the heat transfer advancements. As compared to a conventional aluminum surface, the current research reports a substantial enhancement of the CHF by 112% and an increase of the LPT by 40 K using an aluminum surface with anodized aluminum oxide (AAO) nanoporous texture finish. These heat transfer enhancements imply that the power density would increase by more than 100% and the quenching efficiency would be raised by 33%. A theory that links the nucleation potential of the surface to heat transfer rates has been developed and it successfully explains the current finding by revealing that the heat transfer modification and enhancement are mainly attributed to the superhydrophilic surface property and excessive nanoscale nucleation sites created by the nanoporous surface.

  2. Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hak-Sung Jung

    2012-01-01

    Full Text Available Aminofunctional trialkoxysilanes such as aminopropyltrimethoxysilane (APTMS and (3-trimethoxysilylpropyldiethylenetriamine (DETAS were employed as a surface modification molecule for generating monolayer modification on the surface of silica (SiO2 nanoparticles. We were able to quantitatively analyze the number of amine functional groups on the modified SiO2 nanoparticles by acid-base back titration method and determine the effective number of amine functional groups for the successive chemical reaction by absorption measurements after treating with fluorescent rhodamine B isothiocyanate (RITC molecules. The numbers of amine sites measured by back titration were 2.7 and 7.7 ea/nm2 for SiO2-APTMS and SiO2-DETAS, respectively, while the numbers of effective amine sites measured by absorption calibration were about one fifth of the total amine sites, namely, 0.44 and 1.3 ea/nm2 for SiO2-APTMS(RITC and SiO2-DETAS(RITC, respectively. Furthermore, it was confirmed that the reactivity of amino groups on the surface-modified silica nanoparticles could be maintained in ethanol for more than 1.5 months without showing any significant differences in the reactivity.

  3. Surface modification of polystyrene with atomic oxygen radical anions-dissolved solution

    International Nuclear Information System (INIS)

    Wang Lian; Yan Lifeng; Zhao Peitao; Torimoto, Yoshifumi; Sadakata, Masayoshi; Li Quanxin

    2008-01-01

    A novel approach to surface modification of polystyrene (PS) polymer with atomic oxygen radical anions-dissolved solution (named as O - water) has been investigated. The O - water, generated by bubbling of the O - (atomic oxygen radical anion) flux into the deionized water, was characterized by UV-absorption spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. The O - water treatments caused an obvious increase of the surface hydrophilicity, surface energy, surface roughness and also caused an alteration of the surface chemical composition for PS surfaces, which were indicated by the variety of contact angle and material characterization by atomic force microscope (AFM) imaging, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and attenuated total-reflection Fourier transform infrared (ATR-FTIR) measurements. Particularly, it was found that some hydrophilic groups such as hydroxyl (OH) and carbonyl (C=O) groups were introduced onto the polystyrene surfaces via the O - water treatment, leading to the increases of surface hydrophilicity and surface energy. The active oxygen species would react with the aromatic ring molecules on the PS surfaces and decompose the aromatic compounds to produce hydrophilic hydroxyl and carbonyl compounds. In addition, the O - water is also considered as a 'clean solution' without adding any toxic chemicals and it is easy to be handled at room temperature. Present method may suit to the surface modification of polymers and other heat-sensitive materials potentially

  4. The effects of size and surface modification of amorphous silica particles on biodistribution and liver metabolism in mice

    International Nuclear Information System (INIS)

    Lu, Xiaoyan; Ji, Cai; Jin, Tingting; Fan, Xiaohui

    2015-01-01

    Engineered nanoparticles, with unconventional properties, are promising platforms for biomedical applications. Since they may interact with a wide variety of biomolecules, it is critical to understand the impact of the physicochemical properties of engineered nanoparticles on biological systems. In this study, the effects of particle size and surface modification alone or in combination of amorphous silica particles (SPs) on biological responses were determined using a suite of general toxicological assessments and metabonomics analysis in mice model. Our results suggested that amino or carboxyl surface modification mitigated the liver toxicity of plain-surface SPs. 30 nm SPs with amino surface modification were found to be the most toxic SPs among all the surface-modified SP treatments at the same dosage. When treatment dose was increased, submicro-sized SPs with amino or carboxyl surface modification also induced liver toxicity. Biodistribution studies suggested that 70 nm SPs were mainly accumulated in liver and spleen regardless of surface modifications. Interestingly, these two organs exhibited different uptake trends. Furthermore, metabonomics studies indicated that surface modification plays a more dominant role to affect the liver metabolism than particle size. (paper)

  5. Surface modification of polyacrylonitrile-based carbon fiber and its interaction with imide

    International Nuclear Information System (INIS)

    Xu Bing; Wang Xiaoshu; Lu Yun

    2006-01-01

    In this work, sized polyacrylonitrile (PAN)-based carbon fibers were chemically modified with nitric acid and maleic anhydride (MA) in order to improve the interaction between carbon fiber surface and polyimide matrix. Bismaleimide (BMI) was selected as a model compound of polyimide to react with modified carbon fiber. The surface characteristic changing after modification and surface reaction was investigated by element analysis (EA), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and surface enhanced Raman scattering (SERS). The results indicated that the modification of carbon fiber surface with MA might follow the Diels Alder reaction mechanism. In the surface reaction between modified fibers and BMI, among the various surface functional groups, the hydroxyl group provided from phenolic hydroxyl group and bridged structure on carbon fiber may be the most effective group reacted with imide structure. The results may shed some light on the design of the appropriate surface structure, which could react with polyimide, and the manufacture of the carbon fiber-reinforced polyimide matrix composites

  6. Studies on surface modification of poly(tetrafluoroethylene) film by remote and direct Ar plasma

    International Nuclear Information System (INIS)

    Wang Chen; Chen Jierong; Li Ru

    2008-01-01

    Poly(tetrafluoroethylene) (PTFE) surfaces are modified with remote and direct Ar plasma, and the effects of the modification on the hydrophilicity of PTFE are investigated. The surface microstructures and compositions of the PTFE film were characterized with the goniometer, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results show that the remote and direct plasma treatments modify the PTFE surface in morphology and composition, and both modifications cause surface oxidation of PTFE films, in the forming of some polar functional groups enhancing polymer wettability. When the remote and direct Ar plasma treats PTFE film, the contact angles decrease from the untreated 108-58 o and 65.2 o , respectively. The effect of the remote Ar plasma is more noticeable. The role of all kinds of active species, e.g. electrons, ions and free radicals involved in plasma surface modification is further evaluated. This shows that remote Ar plasma can restrain the ion and electron etching reaction and enhance radical reaction

  7. Modification of surface/neuron interfaces for neural cell-type specific responses: a review

    International Nuclear Information System (INIS)

    Chen, Cen; Kong, Xiangdong; Lee, In-Seop

    2016-01-01

    Surface/neuron interfaces have played an important role in neural repair including neural prostheses and tissue engineered scaffolds. This comprehensive literature review covers recent studies on the modification of surface/neuron interfaces. These interfaces are identified in cases both where the surfaces of substrates or scaffolds were in direct contact with cells and where the surfaces were modified to facilitate cell adhesion and controlling cell-type specific responses. Different sources of cells for neural repair are described, such as pheochromocytoma neuronal-like cell, neural stem cell (NSC), embryonic stem cell (ESC), mesenchymal stem cell (MSC) and induced pluripotent stem cell (iPS). Commonly modified methods are discussed including patterned surfaces at micro- or nano-scale, surface modification with conducting coatings, and functionalized surfaces with immobilized bioactive molecules. These approaches to control cell-type specific responses have enormous potential implications in neural repair. (paper)

  8. Thermal desorption and surface modification of He+ implanted into tungsten

    International Nuclear Information System (INIS)

    Fu Zhang; Yoshida, N.; Iwakiri, H.; Xu Zengyu

    2004-01-01

    Tungsten divertor plates in fusion reactors will be subject to helium bombardment. Helium retention and thermal desorption is a concerned issue in controlling helium ash. In the present study, fluence dependence of thermal desorption behavior of helium in tungsten was studied at different irradiation temperatures and ion energies. Results showed that helium desorption could start at ∼400 K with increasing fluence, while no noticeable peaks were detected at low fluence. Total helium desorption reached a saturation value at high fluence range, which was not sensitive to irradiation temperature or ion energy for the conditions evaluated. Surface modifications caused by either ion irradiation or thermal desorption were observed by SEM. The relationship of surface modifications and helium desorption behavior was discussed. Some special features of elevated irradiation temperature and lower ion energy were also indicated

  9. Surface modification of silicon carbide with silane coupling agent and hexadecyl iodiele

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Xujing, E-mail: shangxujing@tju.edu.cn; Zhu, Yumei, E-mail: zymtju@163.com; Li, Zhihong, E-mail: lzhtju@163.com

    2017-02-01

    Highlights: • A novel universal method was performed to enhance hydrophobicity of SiC powder. • The modification effects of KH550 and KH590 were compared and the optimum reaction parameters were established. • Hexadecyl iodiele was successfully grafted on the surface of SiC-KH590 powder. • Surface changes on SiC powder before and after modification were analyzed via FTIR, XPS, SEM. • The related reaction mechanisms were discussed. - Abstract: In this paper, two kinds of silane coupling agents, namely 3-aminopropyl triethoxysilane (KH550) and 3-mercaptopropyl trimethoxysilane (KH590), were adopted as preliminary modifiers to improve the hydrophobic surface properties of silicon carbide (SiC) powder for the first step. The factors that influence the modification effects were investigated by measuring the contact angle. The results showed that KH590 has a better effect than KH550 for the hydrophobic modification of SiC, and the contact angle improved most after SiC powder was reacted with 0.3 g KH590 at 75 °C in aqueous/alcohol solution for 4 h. On account of further enhancement of hydrophobicity, the study was focused on utilizing nucleophilic substitution between KH590 and hexadecyl iodiele to extend the length of alkyl chain. Compared with using KH590 alone, SiC powder modified by KH590 and hexadecyl iodiele showed better water resistance with an increase of contact angle from 106.8° to 127.5°. The Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectra (XPS) as well as X-ray diffraction (XRD) analysis results showed that KH550/KH590 and hexadecyl iodiele can be covalently bonded to the surface of SiC powder without altering its crystal configuration. This methodology may provide a new way of the modification of inorganic materials in further.

  10. Self-assembling triblock proteins for biofunctional surface modification

    Science.gov (United States)

    Fischer, Stephen E.

    Despite the tremendous promise of cell/tissue engineering, significant challenges remain in engineering functional scaffolds to precisely regulate the complex processes of tissue growth and development. As the point of contact between the cells and the scaffold, the scaffold surface plays a major role in mediating cellular behaviors. In this dissertation, the development and utility of self-assembling, artificial protein hydrogels as biofunctional surface modifiers is described. The design of these recombinant proteins is based on a telechelic triblock motif, in which a disordered polyelectrolyte central domain containing embedded bioactive ligands is flanked by two leucine zipper domains. Under moderate conditions of temperature and pH, the leucine zipper end domains form amphiphilic alpha-helices that reversibly associate into homo-trimeric aggregates, driving hydrogel formation. Moreover, the amphiphilic nature of these helical domains enables surface adsorption to a variety of scaffold materials to form biofunctional protein coatings. The nature and stability of these coatings in various solution conditions, and their interaction with mammalian cells is the primary focus of this dissertation. In particular, triblock protein coatings functionalized with cell recognition sequences are shown to produce well-defined surfaces with precise control over ligand density. The impact of this is demonstrated in multiple cell types through ligand density-dependent cell-substrate interactions. To improve the stability of these physically self-assembled coatings, two covalent crosslinking strategies are described---one in which a zero-length chemical crosslinker (EDC) is utilized and a second in which disulfide bonds are engineered into the recombinant proteins. These targeted crosslinking approaches are shown to increase the stability of surface adsorbed protein layers with minimal effect on the presentation of many bioactive ligands. Finally, to demonstrate the versatility

  11. Surface modification of positive electrode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Julien, C.M., E-mail: Christian.Julien@upmc.fr [Sorbonne Universités, UPMC Univ. Paris 6, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), UMR 8234, 75005 Paris (France); Mauger, A. [Institut de Minéralogie de Physique des Matériaux et de Cosmochimie (IMPMC), UPMC Univ. Paris 6, 4 place Jussieu, 75005 Paris (France); Groult, H. [Sorbonne Universités, UPMC Univ. Paris 6, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), UMR 8234, 75005 Paris (France); Zaghib, K. [Energy Storage and Conversion, Research Institute of Hydro-Québec, Varennes, Québec J3X 1S1 (Canada)

    2014-12-01

    The advanced lithium-ion batteries are critically important for a wide range of applications, from portable electronics to electric vehicles. The research on their electrodes aims to increase the energy density and the power density, improve the calendar and the cycling life, without sacrificing the safety issues. A constant progress through the years has been obtained owing to the surface treatment of the particles, in particular the coating of the nanoparticles with a layer that protects the core region from side reactions with the electrolyte, prevents the loss of oxygen, and the dissolution of the metal ions in the electrolyte, or simply improve the conductivity of the powder. The purpose of the present work is to present the different surface modifications that have been tried for three families of positive electrodes: layered, spinel and olivine frameworks that are currently considered as promising materials. The role of the different coats used to improve either the surface conductivity, or the thermal stability, or the structural integrity is discussed. - Highlights: • Report the various surface modifications tried for the positive electrodes of Li-ion batteries. • The role of different coats used to improve the conductivity, or the thermal stability, or the structural integrity. • Improvement of electrochemical properties of electrodes after coating or surface treatment.

  12. A new green methodology for surface modification of diatomite filler in elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Lamastra, F.R. [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133, Rome (Italy); Mori, S.; Cherubini, V. [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133, Rome (Italy); Department of Enterprise Engineering, University of Rome ' Tor Vergata' , Via del Politecnico 1, 00133, Rome (Italy); Scarselli, M. [Department of Physics, University of Rome ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Rome (Italy); Nanni, F., E-mail: fnanni@ing.uniroma2.it [Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata, Via del Politecnico 1, 00133, Rome (Italy); Department of Enterprise Engineering, University of Rome ' Tor Vergata' , Via del Politecnico 1, 00133, Rome (Italy)

    2017-06-15

    In this work a new, simple and green protocol to introduce a limited content of silanol groups on the surface of an hydrophobic diatomite, in order to be slightly hydrophilic and susceptible to be silanized by bifunctional, sulfur-containing organosilanes for rubber applications, is proposed. The chemical modification was carried out at 85 °C in a solution of H{sub 2}O:NaOH:H{sub 2}O{sub 2}. The modified diatomite was then silanized with bis(triethoxysilylpropyl) disulfide by a procedure that does not involve toxic solvent. Morphological features and elemental composition of diatomite were investigated by Field emission scanning electron microscopy coupled with Energy dispersive X-ray spectroscopy. The surface modification and silanization process were assessed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Diatomite was composed by micrometric frustules from different diatom species with pore size ranging from 25 nm to 1 μm. The spectroscopic characterizations confirmed the surface modification of diatomite with some silanols that acted as sites for silanization reaction. The silanized diatomite and the untreated one were used as filler in unvulcanized solvent-cast SBR films in order to verify that the modification does not negatively affect the polymer/filler interface and as consequence the mechanical properties. Mechanical properties of the realized samples were assessed by uniaxial tensile tests. Films filled with 10 wt% of diatomite (untreated or silanized) showed an increase of Elastic Modulus about of 50% and a decrease of the strain at break with respect to SBR samples, while the tensile strength was not significantly affected by the diatomite addition. SEM images of fracture surfaces of tested specimens showed a fine dispersion of both untreated and silanized diatomite in the polymeric matrix and the achieving of a good interfacial adhesion SBR/fillers. The silanized diatomite, as it is potentially able to bind

  13. A new green methodology for surface modification of diatomite filler in elastomers

    International Nuclear Information System (INIS)

    Lamastra, F.R.; Mori, S.; Cherubini, V.; Scarselli, M.; Nanni, F.

    2017-01-01

    In this work a new, simple and green protocol to introduce a limited content of silanol groups on the surface of an hydrophobic diatomite, in order to be slightly hydrophilic and susceptible to be silanized by bifunctional, sulfur-containing organosilanes for rubber applications, is proposed. The chemical modification was carried out at 85 °C in a solution of H_2O:NaOH:H_2O_2. The modified diatomite was then silanized with bis(triethoxysilylpropyl) disulfide by a procedure that does not involve toxic solvent. Morphological features and elemental composition of diatomite were investigated by Field emission scanning electron microscopy coupled with Energy dispersive X-ray spectroscopy. The surface modification and silanization process were assessed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Diatomite was composed by micrometric frustules from different diatom species with pore size ranging from 25 nm to 1 μm. The spectroscopic characterizations confirmed the surface modification of diatomite with some silanols that acted as sites for silanization reaction. The silanized diatomite and the untreated one were used as filler in unvulcanized solvent-cast SBR films in order to verify that the modification does not negatively affect the polymer/filler interface and as consequence the mechanical properties. Mechanical properties of the realized samples were assessed by uniaxial tensile tests. Films filled with 10 wt% of diatomite (untreated or silanized) showed an increase of Elastic Modulus about of 50% and a decrease of the strain at break with respect to SBR samples, while the tensile strength was not significantly affected by the diatomite addition. SEM images of fracture surfaces of tested specimens showed a fine dispersion of both untreated and silanized diatomite in the polymeric matrix and the achieving of a good interfacial adhesion SBR/fillers. The silanized diatomite, as it is potentially able to bind chemically to

  14. Surface modification of polyethylene by diffuse barrier discharge plasma

    Czech Academy of Sciences Publication Activity Database

    Novák, I.; Števiar, M.; Popelka, A.; Chodák, I.; Mosnáček, J.; Špírková, Milena; Janigová, I.; Kleinová, A.; Sedliačik, J.; Šlouf, Miroslav

    2013-01-01

    Roč. 53, č. 3 (2013), s. 516-523 ISSN 0032-3888 R&D Projects: GA AV ČR(CZ) IAAX08240901 Institutional research plan: CEZ:AV0Z40500505 Keywords : low-density polyethylene * plasma discharge * surface modification Subject RIV: JI - Composite Materials Impact factor: 1.441, year: 2013

  15. Selective cell culture on UV transparent polymer by F2 laser surface modification

    International Nuclear Information System (INIS)

    Hanada, Yasutaka; Sugioka, Koji; Kawano, Hiroyuki; Tsuchimoto, Takayoshi; Miyamoto, Iwao; Miyawaki, Atsushi; Midorikawa, Katsumi

    2009-01-01

    A microchip made of UV transparent polymer (CYTOP) that can perform selective cell culture has been fabricated by F 2 laser surface modification. The refractive index of CYTOP is almost the same as that of culture medium, which is essential for three-dimensional (3D) observation of cells. The F 2 laser modification of CYTOP achieves hydrophilicity only on the laser irradiated area with little deterioration of the optical properties and surface smoothness. After the laser modification, HeLa cells were successfully cultured and strongly adhered only on the modified area of CYTOP. The cells patterned on CYTOP were applied for clear 3D observation using an optical microscope in phase contrast mode.

  16. Biomimetic surface modification of polypropylene by surface chain transfer reaction based on mussel-inspired adhesion technology and thiol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Zhijun; Zhao, Yang; Sun, Wei; Shi, Suqing, E-mail: shisq@nwu.edu.cn; Gong, Yongkuan

    2016-11-15

    Highlights: • Biomimetic surface modification of PP was successfully conducted by integrating mussel-inspired technology, thiol chemistry and cell outer membranes-like structures. • The resultant biomimetic surface exhibits good interface and surface stability. • The obvious suppression of protein adsorption and platelet adhesion is also achieved. • The residue thoil groups on the surface could be further functionalized. - Abstract: Biomimetic surface modification of polypropylene (PP) is conducted by surface chain transfer reaction based on the mussel-inspired versatile adhesion technology and thiol chemistry, using 2-methacryloyloxyethylphosphorylcholine (MPC) as a hydrophilic monomer mimicking the cell outer membrane structure and 2,2-azobisisobutyronitrile (AIBN) as initiator in ethanol. A layer of polydopamine (PDA) is firstly deposited onto PP surface, which not only offers good interfacial adhesion with PP, but also supplies secondary reaction sites (-NH{sub 2}) to covalently anchor thiol groups onto PP surface. Then the radical chain transfer to surface-bonded thiol groups and surface re-initiated polymerization of MPC lead to the formation of a thin layer of polymer brush (PMPC) with cell outer membrane mimetic structure on PP surface. X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle measurements are used to characterize the PP surfaces before and after modification. The protein adsorption and platelet adhesion experiments are also employed to evaluate the interactions of PP surface with biomolecules. The results show that PMPC is successfully grafted onto PP surface. In comparison with bare PP, the resultant PP-PMPC surface exhibits greatly improved protein and platelet resistance performance, which is the contribution of both increased surface hydrophilicity and zwitterionic structure. More importantly, the residue thiol groups on PP-PMPC surface create a new pathway to further functionalize such

  17. Biomimetic surface modification of polypropylene by surface chain transfer reaction based on mussel-inspired adhesion technology and thiol chemistry

    International Nuclear Information System (INIS)

    Niu, Zhijun; Zhao, Yang; Sun, Wei; Shi, Suqing; Gong, Yongkuan

    2016-01-01

    Highlights: • Biomimetic surface modification of PP was successfully conducted by integrating mussel-inspired technology, thiol chemistry and cell outer membranes-like structures. • The resultant biomimetic surface exhibits good interface and surface stability. • The obvious suppression of protein adsorption and platelet adhesion is also achieved. • The residue thoil groups on the surface could be further functionalized. - Abstract: Biomimetic surface modification of polypropylene (PP) is conducted by surface chain transfer reaction based on the mussel-inspired versatile adhesion technology and thiol chemistry, using 2-methacryloyloxyethylphosphorylcholine (MPC) as a hydrophilic monomer mimicking the cell outer membrane structure and 2,2-azobisisobutyronitrile (AIBN) as initiator in ethanol. A layer of polydopamine (PDA) is firstly deposited onto PP surface, which not only offers good interfacial adhesion with PP, but also supplies secondary reaction sites (-NH 2 ) to covalently anchor thiol groups onto PP surface. Then the radical chain transfer to surface-bonded thiol groups and surface re-initiated polymerization of MPC lead to the formation of a thin layer of polymer brush (PMPC) with cell outer membrane mimetic structure on PP surface. X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle measurements are used to characterize the PP surfaces before and after modification. The protein adsorption and platelet adhesion experiments are also employed to evaluate the interactions of PP surface with biomolecules. The results show that PMPC is successfully grafted onto PP surface. In comparison with bare PP, the resultant PP-PMPC surface exhibits greatly improved protein and platelet resistance performance, which is the contribution of both increased surface hydrophilicity and zwitterionic structure. More importantly, the residue thiol groups on PP-PMPC surface create a new pathway to further functionalize such

  18. The effects of surface modification on carbon felt electrodes for use in vanadium redox flow batteries

    International Nuclear Information System (INIS)

    Kim, Ki Jae; Kim, Young-Jun; Kim, Jae-Hun; Park, Min-Sik

    2011-01-01

    Highlights: ► We observed the physical and chemical changes on the surface of carbon felts after various surface modifications. ► The surface area and chemistry of functional groups formed on the surface of carbon felt are critical to determine the kinetics of the redox reactions of vanadium ions. ► By incorporation of the surface modifications into the electrode preparation, the electrochemical activity of carbon felts could be notably enhanced. - Abstract: The surface of carbon felt electrodes has been modified for improving energy efficiency of vanadium redox flow batteries. For comparative purposes, the effects of various surface modifications such as mild oxidation, plasma treatment, and gamma-ray irradiation on the electrochemical properties of carbon felt electrodes were investigated at optimized conditions. The cell energy efficiency was improved from 68 to 75% after the mild oxidation of the carbon felt at 500 °C for 5 h. This efficiency improvement could be attributed to the increased surface area of the carbon felt electrode and the formation of functional groups on its surface as a result of the modification. On the basis of various structural and electrochemical characterizations, a relationship between the surface nature and electrochemical activity of the carbon felt electrodes is discussed.

  19. Chemical surface reactions by click chemistry: coumarin dye modification of 11-bromoundecyltrichlorosilane monolayers

    International Nuclear Information System (INIS)

    Haensch, Claudia; Hoeppener, Stephanie; Schubert, Ulrich S

    2008-01-01

    The functionalization of surfaces and the ability to tailor their properties with desired physico-chemical functions is an important field of research with a broad spectrum of applications. These applications range from the modification of wetting properties, over the alteration of optical properties, to the fabrication of molecular electronic devices. In each of these fields, it is of specific importance to be able to control the quality of the layers with high precision. The present study demonstrates an approach that utilizes the 1,3-dipolar cycloaddition of terminal acetylenes to prepare triazole-terminated monolayers on different substrates. The characterization of the precursor monolayers, the optimization of the chemical surface reactions as well as the clicking of a fluorescent dye molecule on such azide-terminated monolayers was carried out. A coumarin 343 derivative was utilized to discuss the aspects of the functionalization approach. Based on this approach, a number of potential surface reactions, facilitated via the acetylene-substituted functional molecules, for a broad range of applications is at hand, thus leading to numerous possibilities where surface modifications are concerned. These modifications can be applied on non-structured surfaces of silicon or glass or can be used on structured surfaces. Various possibilities are discussed

  20. Direct modification of silicon surface by nanosecond laser interference lithography

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Wang, Zuobin, E-mail: wangz@cust.edu.cn [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Zhang, Ziang [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); Yue, Yong [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Li, Dayou [JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom); Maple, Carsten [JR3CN and CNM (Changchun University of Science and Technology), Changchun 130022 (China); JR3CN and IRAC (University of Bedfordshire), Luton LU1 3JU (United Kingdom)

    2013-10-01

    Periodic and quasi-periodic structures on silicon surface have numerous significant applications in photoelectronics and surface engineering. A number of technologies have been developed to fabricate the structures in various research fields. In this work, we take the strategy of direct nanosecond laser interference lithography technology, and focus on the silicon material to create different well-defined surface structures based on theoretical analysis of the formation of laser interference patterns. Two, three and four-beam laser interference systems were set up to fabricate the grating, regular triangle and square structures on silicon surfaces, respectively. From the AFM micrographs, the critical features of structures have a dependence on laser fluences. For a relative low laser fluence, grating and dot structures formed with bumps due to the Marangoni Effect. With the increase of laser fluences, melt and evaporation behaviors can be responsible for the laser modification. By properly selecting the process parameters, well-defined grating and dot structures can been achieved. It can be demonstrated that direct laser interference lithography is a facile and efficient technology with the advantage of a single process procedure over macroscale areas for the fabrication of micro and nano structures.

  1. Surface Modification of Ceramic Membranes with Thin-film Deposition Methods for Wastewater Treatment

    KAUST Repository

    Jahangir, Daniyal

    2017-12-01

    Membrane fouling, which is caused by deposition/adsorption of foulants on the surface or within membrane pores, still remains a bottleneck that hampers the widespread application of membrane bioreactor (MBR) technology for wastewater treatment. Recently membrane surface modification has proved to be a useful method in water/wastewater treatment to improve the surface hydrophilicity of membranes to obtain higher water fluxes and to reduce fouling. In this study, membrane modification was investigated by depositing a thin film of same thickness of TiO2 on the surface of an ultrafiltration alumina membrane. Various thin-film deposition (TFD) methods were employed, i.e. electron-beam evaporation, sputter and atomic layer deposition (ALD), and a comparative study of the methods was conducted to assess fouling inhibition performance in a lab-scale anaerobic MBR (AnMBR) fed with synthetic municipal wastewater. Thorough surface characterization of all modified membranes was carried out along with clean water permeability (CWP) tests and fouling behavior by bovine serum albumin (BSA) adsorption tests. The study showed better fouling inhibition performance of all modified membranes; however the effect varied due to different surface characteristics obtained by different deposition methods. As a result, ALD-modified membrane showed a superior status in terms of surface characteristics and fouling inhibition performance in AnMBR filtration tests. Hence ALD was determined to be the best TFD method for alumina membrane surface modification for this study. ALD-modified membranes were further characterized to determine an optimum thickness of TiO2-film by applying different ALD cycles. ALD treatment significantly improved the surface hydrophilicity of the unmodified membrane. Also ALD-TiO2 modification was observed to reduce the surface roughness of original alumina membrane, which in turn enhanced the anti-fouling properties of modified membranes. Finally, a same thickness of ALD

  2. Surface chemical modification for exceptional wear life of MEMS materials

    Directory of Open Access Journals (Sweden)

    R. Arvind Singh

    2011-12-01

    Full Text Available Micro-Electro-Mechanical-Systems (MEMS are built at micro/nano-scales. At these scales, the interfacial forces are extremely strong. These forces adversely affect the smooth operation and cause wear resulting in the drastic reduction in wear life (useful operating lifetime of actuator-based devices. In this paper, we present a surface chemical modification method that reduces friction and significantly extends the wear life of the two most popular MEMS structural materials namely, silicon and SU-8 polymer. The method includes surface chemical treatment using ethanolamine-sodium phosphate buffer, followed by coating of perfluoropolyether (PFPE nanolubricant on (i silicon coated with SU-8 thin films (500 nm and (ii MEMS process treated SU-8 thick films (50 μm. After the surface chemical modification, it was observed that the steady-state coefficient of friction of the materials reduced by 4 to 5 times and simultaneously their wear durability increased by more than three orders of magnitude (> 1000 times. The significant reduction in the friction coefficients is due to the lubrication effect of PFPE nanolubricant, while the exceptional increase in their wear life is attributed to the bonding between the -OH functional group of ethanolamine treated SU-8 thin/thick films and the -OH functional group of PFPE. The surface chemical modification method acts as a common route to enhance the performance of both silicon and SU-8 polymer. It is time-effective (process time ≤ 11 min, cost-effective and can be readily integrated into MEMS fabrication/assembly processes. It can also work for any kind of structural material from which the miniaturized devices are/can be made.

  3. Air-spun PLA nanofibers modified with reductively sheddable hydrophilic surfaces for vascular tissue engineering: synthesis and surface modification.

    Science.gov (United States)

    Ko, Na Re; Sabbatier, Gad; Cunningham, Alexander; Laroche, Gaétan; Oh, Jung Kwon

    2014-02-01

    Polylactide (PLA) is a class of promising biomaterials that hold great promise for various biological and biomedical applications, particularly in the field of vascular tissue engineering where it can be used as a fibrous mesh to coat the inside of vascular prostheses. However, its hydrophobic surface providing nonspecific interactions and its limited ability to further modifications are challenges that need to be overcome. Here, the development of new air-spun PLA nanofibers modified with hydrophilic surfaces exhibiting reduction response is reported. Surface-initiated atom transfer radical polymerization allows for grafting pendant oligo(ethylene oxide)-containing polymethacrylate (POEOMA) from PLA air-spun fibers labeled with disulfide linkages. The resulting PLA-ss-POEOMA fibers exhibit enhanced thermal stability and improved surface properties, as well as thiol-responsive shedding of hydrophilic POEOMA by the cleavage of its disulfide linkages in response to reductive reactions, thus tuning the surface properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Surface Modification and Surface - Subsurface Exchange Processes on Europa

    Science.gov (United States)

    Phillips, C. B.; Molaro, J.; Hand, K. P.

    2017-12-01

    The surface of Jupiter's moon Europa is modified by exogenic processes such as sputtering, gardening, radiolysis, sulfur ion implantation, and thermal processing, as well as endogenic processes including tidal shaking, mass wasting, and the effects of subsurface tectonic and perhaps cryovolcanic activity. New materials are created or deposited on the surface (radiolysis, micrometeorite impacts, sulfur ion implantation, cryovolcanic plume deposits), modified in place (thermal segregation, sintering), transported either vertically or horizontally (sputtering, gardening, mass wasting, tectonic and cryovolcanic activity), or lost from Europa completely (sputtering, plumes, larger impacts). Some of these processes vary spatially, as visible in Europa's leading-trailing hemisphere brightness asymmetry. Endogenic geologic processes also vary spatially, depending on terrain type. The surface can be classified into general landform categories that include tectonic features (ridges, bands, cracks); disrupted "chaos-type" terrain (chaos blocks, matrix, domes, pits, spots); and impact craters (simple, complex, multi-ring). The spatial distribution of these terrain types is relatively random, with some differences in apex-antiapex cratering rates and latitudinal variation in chaos vs. tectonic features. In this work, we extrapolate surface processes and rates from the top meter of the surface in conjunction with global estimates of transport and resurfacing rates. We combine near-surface modification with an estimate of surface-subsurface (and vice versa) transport rates for various geologic terrains based on an average of proposed formation mechanisms, and a spatial distribution of each landform type over Europa's surface area. Understanding the rates and mass balance for each of these processes, as well as their spatial and temporal variability, allows us to estimate surface - subsurface exchange rates over the average surface age ( 50myr) of Europa. Quantifying the timescale

  5. Surface Modification of Sputtered Ga.5In.5Sb Thin Films ISHU ...

    African Journals Online (AJOL)

    MICHAEL

    IR detectors useful for fiber optic communication. Since the efficiency of detector depends very much on the surface properties of the substrate material, improvement of substrate surfaces is a challenging task in device technology. Reports on the improved electrical properties of GaAs and InP surfaces by. Ru3+ modification ...

  6. Effects of surface modification on the critical behaviour in multiple-surface-layer ferroelectric thin films

    International Nuclear Information System (INIS)

    Lu, Z X

    2013-01-01

    Using the usual mean-field theory approximation, the critical behaviour (i.e. the Curie temperature T c and the critical surface transverse field Ω sc ) in a multiple-surface-layer ferroelectric thin film is studied on the basis of the spin- 1/2 transverse Ising model. The dependence of the Curie temperature T c on the surface transverse field Ω s and the surface layer number N s are discussed in detail. Meanwhile the dependence of the critical surface transverse field Ω sc on the surface layer number N s is also examined. The numerical results indicate that the critical behaviour of ferroelectric thin films is obviously affected by modifications of the surface transverse field Ω s and surface layer number N s .

  7. Modification of Au surfaces using new ferrocene derivatives

    International Nuclear Information System (INIS)

    Diaz-Ortiz, Tanya L.; Malave-Leon, Maria; Rivera-Claudio, Mirna; Castillo-Ramirez, Jorge; Cabrera-Martinez, Carlos R.; Brito-Gomez, Rosa; Tremont, Rolando J.

    2008-01-01

    Gold surfaces have been modified by self-assembled techniques. Here the adsorption time of diasteroisomers (1R, 3S)-1-ferrocenyl-3-methyl-4,4-diphenyl-2,5-dioxacyclopentane and (1S, 3S)-1-ferrocenyl-3-methyl-4,4-diphenyl-2,5-dioxacyclopentane (, 3a and 3b) at a Au surface in ethanol solution was controlled. This study was followed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) analysis. The method used for the surface modification was the control of exposure time of a Au surface in the modifier/ethanol solution. It was demonstrated by EIS and XPS that the Au surface was modified with mixture of compounds 3a + 3b, avoiding the electron transference in the interface. It was also observed that the organometallic molecule indeed had been adsorbed on the Au surface. In addition, evidence seems to conclude that the molecule-Au interaction is through the electrons of cyclopentadienyl moiety, where the oxygen atoms are near the air-molecule interface and the iron atom is near the Au surface. This type of interaction of the ferrocene derivatives with gold surfaces has not been reported by any other author

  8. Deaggregation, Modification, and Developing Applications for Detonation Nanodiamond

    Science.gov (United States)

    Mochalin, Vadym

    2017-06-01

    Nanodiamond powder (ND) is one of the most promising materials for advanced composites and biomedical applications. It is also a commercial precursor for carbon nanoonions - material for high power micrometer size supercapacitors and potentially, Li-ion batteries. ND is produced by detonation of explosives with negative oxygen balance in a closed chamber, where extremely high pressures and temperatures develop during detonation. ND consists of diamond particles of 5 nm diameter, combining fully accessible large surface and rich and tailorable surface chemistry. ND has unique properties including optical, electrical, thermal, and mechanical, and is biocompatible and non-toxic. Due to numerous surface functional groups, ND has catalytic and electrochemical activity. Several techniques have been proposed for ND deaggregation based on milling with costly ceramic microbeads, leaving difficult to remove contaminations in the resulting ND suspension. We have recently discovered a novel, green technique for ND deaggregation using sonication in aqueous sodium chloride slurry. Upon completion of the process sodium chloride can be easily washed out with water leaving behind no contaminants and yielding stable single-digit ND colloids. Modification and development of applications for ND in composites, drug delivery, biomedical imaging, etc., will be also discussed.

  9. Laser-assisted modification of polystyrene surfaces for cell culture applications

    International Nuclear Information System (INIS)

    Pfleging, Wilhelm; Bruns, Michael; Welle, Alexander; Wilson, Sandra

    2007-01-01

    Laser-assisted patterning and modification of polystyrene (PS) was investigated with respect to applications in micro-fluidics and cell culture. For this purpose the wettability, the adsorption of proteins and the adhesion of animal cells were investigated as function of laser- and processing parameters. The change of surface chemistry was characterized by X-ray photoelectron spectroscopy. The local formation of chemical structures suitable for improved cell adhesion was realized on PS surfaces by UV laser irradiation. Above and below the laser ablation threshold two different mechanisms affecting cell adhesion were detected. In the first case the debris deposited on and along laser irradiated areas was responsible for improved cell adhesion, while in the second case a photolytic activation of the polymer surface including a subsequent oxidization in oxygen or ambient air is leading to a highly localized alteration of protein adsorption from cell culture media and finally to increased cell adhesion. Laser modifications of PS using suitable exposure doses and an appropriate choice of the processing gas (helium or oxygen) enabled a highly localized control of wetting. The dynamic advancing contact angle could be adjusted between 2 o and 150 o . The hydrophilic and hydrophobic behaviour are caused by chemical and topographical surface changes

  10. Effects of surface modification on the mechanical and structural properties of nanofibrous poly(ε-caprolactone)/forsterite scaffold for tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Kharaziha, M., E-mail: Kharaziha.ma@yahoo.com [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Fathi, M.H. [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Edris, H. [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of); Department of Materials Engineering, Isfahan University of Technology, Isfahan 8415683111 (Iran, Islamic Republic of)

    2013-12-01

    Composite scaffolds consisting of polymers reinforced with ceramic nanoparticles are widely applied for hard tissue engineering. However, due to the incompatible polarity of ceramic nanoparticles with polymers, they tend to agglomerate in the polymer matrix which results in undesirable effects on the integral properties of composites. In this research, forsterite (Mg{sub 2}SiO{sub 4}) nanoparticles was surface esterified by dodecyl alcohol and nanofibrous poly(ε-caprolactone)(PCL)/modified forsterite scaffolds were developed through electrospinning technique. The aim of this research was to investigate the properties of surface modified forsterite nanopowder and PCL/modified forsterite scaffolds, before and after hydrolytic treatment, as well as the cellular attachment and proliferation. Results demonstrated that surface modification of nanoparticles significantly enhanced the tensile strength and toughness of scaffolds upon 1.5- and 4-folds compared to unmodified samples, respectively, due to improved compatibility between matrix and filler. Hydrolytic treatment of scaffolds also modified the bioactivity and cellular attachment and proliferation due to greatly enhanced hydrophilicity of the forsterite nanoparticles after this process compared to surface modified samples. Results suggested that surface modification of forsterite nanopowder and hydrolytic treatment of the developed scaffolds were effective approaches to address the issues in the formation of composite fibers and resulted in development of bioactive composite scaffolds with ideal mechanical and structural properties for bone tissue engineering applications. - Highlights: • Forsterite nanopowder was surface modified with dodecyl alcohol. • Nanofibrous PCL/forsterite scaffolds were developed through electrospinning. • Composite scaffolds were treated in boiled water to remove the dodecyl chains. • Surface modification resulted in improved mechanical properties. • Hydrolytic treatment

  11. Construction of mechanically durable superhydrophobic surfaces by thermal spray deposition and further surface modification

    Science.gov (United States)

    Chen, Xiuyong; Gong, Yongfeng; Suo, Xinkun; Huang, Jing; Liu, Yi; Li, Hua

    2015-11-01

    Here we report a simple and cost-effective technical route for constructing superhydrophobic surfaces with excellent abrasion resistance on various substrates. Rough surface structures were fabricated by thermal spray deposition of a variety of inorganic materials, and further surface modification was made by applying a thin layer of polytetrafluoroethylene. Results show that the Al, Cu, or NiCrBSi coatings with the surface roughness of up to 13.8 μm offer rough surface profile to complement the topographical morphology in micro-/nano-scaled sizes, and the hydrophobic molecules facilitate the hydrophobicity. The contact angles of water droplets of ∼155° with a sliding angle of up to 3.5° on the samples have been achieved. The newly constructed superhydrophobic coatings tolerate strong abrasion, giving clear insight into their long-term functional applications.

  12. Surface modification of closed plastic bags for adherent cell cultivation

    Science.gov (United States)

    Lachmann, K.; Dohse, A.; Thomas, M.; Pohl, S.; Meyring, W.; Dittmar, K. E. J.; Lindenmeier, W.; Klages, C.-P.

    2011-07-01

    In modern medicine human mesenchymal stem cells are becoming increasingly important. However, a successful cultivation of this type of cells is only possible under very specific conditions. Of great importance, for instance, are the absence of contaminants such as foreign microbiological organisms, i.e., sterility, and the chemical functionalization of the ground on which the cells are grown. As cultivation of these cells makes high demands, a new procedure for cell cultivation has been developed in which closed plastic bags are used. For adherent cell growth chemical functional groups have to be introduced on the inner surface of the plastic bag. This can be achieved by a new, atmospheric-pressure plasma-based method presented in this paper. The method which was developed jointly by the Fraunhofer IST and the Helmholtz HZI can be implemented in automated equipment as is also shown in this contribution. Plasma process gases used include helium or helium-based gas mixtures (He + N2 + H2) and vapors of suitable film-forming agents or precursors such as APTMS, DACH, and TMOS in helium. The effect of plasma treatment is investigated by FTIR-ATR spectroscopy as well as surface tension determination based on contact angle measurements and XPS. Plasma treatment in nominally pure helium increases the surface tension of the polymer foil due to the presence of oxygen traces in the gas and oxygen diffusing through the gas-permeable foil, respectively, reacting with surface radical centers formed during contact with the discharge. Primary amino groups are obtained on the inner surface by treatment in mixtures with nitrogen and hydrogen albeit their amount is comparably small due to diffusion of oxygen through the gas-permeable bag, interfering with the plasma-amination process. Surface modifications introducing amino groups on the inner surface turned out to be most efficient in the promotion of cell growth.

  13. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    International Nuclear Information System (INIS)

    Verma, Pallavi; Maire, Pascal; Novak, Petr

    2011-01-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH 2 ) 3 OCO 2 Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C 6 H 4 NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C 6 H 4 CH 2 OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  14. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Pallavi; Maire, Pascal [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland); Novak, Petr, E-mail: petr.novak@psi.c [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland)

    2011-04-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH{sub 2}){sub 3}OCO{sub 2}Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C{sub 6}H{sub 4}NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C{sub 6}H{sub 4}CH{sub 2}OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  15. Pool boiling CHF enhancement by micro/nanoscale modification of zircaloy-4 surface

    International Nuclear Information System (INIS)

    Ahn, Ho Seon; Lee, Chan; Kim, Hyungdae; Jo, HangJin; Kang, SoonHo; Kim, Joonwon; Shin, Jeongseob; Kim, Moo Hwan

    2010-01-01

    Consideration of the critical heat flux (CHF) requires difficult compromises between economy and safety in many types of thermal systems, including nuclear power plants. Much research has been directed towards enhancing the CHF, and many recent studies have revealed that the significant CHF enhancement in nanofluids is due to surface deposition of nanoparticles. The surface deposition of nanoparticles influenced various surface characteristics. This fact indicated that the surface wettability is a key parameter for CHF enhancement and so is the surface morphology. In this study, surface wettability of zircaloy-4 used as cladding material of fuel rods in nuclear power plants was modified using surface treatment technique (i.e. anodization). Pool boiling experiments of distilled water on the prepared surfaces was conducted at atmospheric and saturated conditions to examine effects of the surface modification on CHF. The experimental results showed that CHF of zircaloy-4 can be significantly enhanced by the improvement in surface wettability using the surface modification, but only the wettability effect cannot explain the CHF increase on the treated zircaloy-4 surfaces completely. It was found that below a critical value of contact angle (10 o ), micro/nanostructures created by the surface treatment increased spreadability of liquid on the surface, which could lead to further increase in CHF even beyond the prediction caused only by the wettability improvement. These micro/nanostructures with multiscale on heated surface induced more significant CHF enhancement than it based on the wettability effect, due to liquid spreadability.

  16. Plasma immersion ion implantation for the efficient surface modification of medical materials

    International Nuclear Information System (INIS)

    Slabodchikov, Vladimir A.; Borisov, Dmitry P.; Kuznetsov, Vladimir M.

    2015-01-01

    The paper reports on a new method of plasma immersion ion implantation for the surface modification of medical materials using the example of nickel-titanium (NiTi) alloys much used for manufacturing medical implants. The chemical composition and surface properties of NiTi alloys doped with silicon by conventional ion implantation and by the proposed plasma immersion method are compared. It is shown that the new plasma immersion method is more efficient than conventional ion beam treatment and provides Si implantation into NiTi surface layers through a depth of a hundred nanometers at low bias voltages (400 V) and temperatures (≤150°C) of the substrate. The research results suggest that the chemical composition and surface properties of materials required for medicine, e.g., NiTi alloys, can be successfully attained through modification by the proposed method of plasma immersion ion implantation and by other methods based on the proposed vacuum equipment without using any conventional ion beam treatment

  17. Laser surface modification of stainless steels for cavitation erosion resistance

    Science.gov (United States)

    Kwok, Chi Tat

    1999-12-01

    Austenitic stainless steel UNS S31603 (Fe -17.6Cr -11.2Ni -2.5Mo -1.4Mn -0.4Si -0.03C) has higher pitting corrosion resistance but lower cavitation erosion resistance than that of UNS S30400. This is because of its lower tendency for strain induced martensitic transformation and higher stacking fault energy as compared with those of UNS S30400. In order to improve its cavitation erosion resistance, surface modification of S31603 was performed by laser surface melting and laser surface alloying using a 2-kW CW Nd-YAG laser and a 3-kW CW CO2 laser. For laser surface melting, austenitic stainless steel UNS S30400, super duplex stainless steel UNS S32760 and martensitic stainless steel UNS S42000 were also investigated for comparison purpose. For laser surface alloying, alloying materials including various elements (Co, Cr, Ni, Mo, Mn, Si & C), alloys (AlSiFe & NiCrSiB), ceramics (Si3N 4, SiC, Cr3C2, TiC, CrB & Cr2O 3) and alloys-ceramics (Co-WC, Ni-WC, Ni-Al2O3, Ni-Cr2C3) were used to modify the surface of S31603. The alloyed surface was achieved first by flame spraying or pre-placing of the alloy powder on the S31603 surface and then followed by laser surface remelting. The cavitation erosion characteristics of laser surface modified specimens in 3.5% NaCl solution at 23°C were studied by means of a 20-kHz ultrasonic vibrator at a peak-to-peak amplitude of 30 mum. In addition, their pitting corrosion behaviour was evaluated by electrochemical techniques. The microstructures, compositions, phase changes and damage mechanisms under cavitation erosion were investigated by optical microscopy, SEM, EDAX and X-ray diffractometry. Mechanical properties such as microhardness profile were also examined. The cavitation erosion resistance Re (reciprocal of the mean depth of penetration rate) of laser surface melted S31603 was found to be improved by 22% and was attributed to the existence of tensile residual stress. Improvement on the Re of S42000 was found to be 8.5 times

  18. Selective cell culture on UV transparent polymer by F{sub 2} laser surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Hanada, Yasutaka, E-mail: y-hanada@riken.jp [RIKEN-Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sugioka, Koji [RIKEN-Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawano, Hiroyuki [RIKEN-Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsuchimoto, Takayoshi [RIKEN-Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Applied Electronics, Faculty of Industrial Science and Technology Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Miyamoto, Iwao [Department of Applied Electronics, Faculty of Industrial Science and Technology Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Miyawaki, Atsushi [RIKEN-Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Midorikawa, Katsumi [RIKEN-Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2009-09-30

    A microchip made of UV transparent polymer (CYTOP) that can perform selective cell culture has been fabricated by F{sub 2} laser surface modification. The refractive index of CYTOP is almost the same as that of culture medium, which is essential for three-dimensional (3D) observation of cells. The F{sub 2} laser modification of CYTOP achieves hydrophilicity only on the laser irradiated area with little deterioration of the optical properties and surface smoothness. After the laser modification, HeLa cells were successfully cultured and strongly adhered only on the modified area of CYTOP. The cells patterned on CYTOP were applied for clear 3D observation using an optical microscope in phase contrast mode.

  19. Surface modification of magnesium hydroxide sulfate hydrate whiskers using a silane coupling agent by dry process

    International Nuclear Information System (INIS)

    Zhu, Donghai; Nai, Xueying; Lan, Shengjie; Bian, Shaoju; Liu, Xin; Li, Wu

    2016-01-01

    Highlights: • Dry process was adopted to modify the surface of MHSH whiskers using silane. • Si−O−Mg bonds were formed directly by the reaction between Si−OC 2 H 5 and −OH of MHSH. • Dispersibility and compatibility of modified whiskers greatly improved in organic phase. • Thermal stability of whiskers was enhanced after modified. - Abstract: In order to improve the compatibility of magnesium hydroxide sulfate hydrate (MHSH) whiskers with polymers, the surface of MHSH whiskers was modified using vinyltriethoxysilane (VTES) by dry process. The possible mechanism of the surface modification and the interfacial interactions between MHSH whiskers and VTES, as well as the effect of surface modification, were studied. Scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analyses showed that the agglomerations were effectively separated and a thin layer was formed on the surface of the whiskers after modification. Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses showed that the VTES molecules were bound to the surface of MHSH whiskers after modification. Chemical bonds (Si−O−Mg) were formed by the reaction between Si−OC 2 H 5 or Si−OH and the hydroxyl group of MHSH whiskers. The effect of surface modification was evaluated by sedimentation tests, contact angle measurements and thermogravimetric analysis (TGA). The results showed that the surface of MHSH whiskers was transformed from hydrophilic to hydrophobic, and the dispersibility and the compatibility of MHSH whiskers were significantly improved in the organic phase. Additionally, the thermal stability of the VTES-modified MHSH whiskers was improved significantly.

  20. Processing and surface modification of novel natural-origin architectures aimed for biomedical applications

    Science.gov (United States)

    Silva, Simone dos Santos

    In the last decades, tissue engineering has emerged as a potential therapeutical tool aimed at developing substitutes that are able to restore proper function of the damaged organs/tissues. Nature-inspired routes involving natural origin polymer-based systems represent an attractive alternative to produce novel materials by mimicking the tissue environment required for tissue regeneration. Moreover, further modifications of these systems allow the adjustment of their properties in accordance with the requirements for successful biomedical applications. The main goal of the present thesis is to develop and modify natural origin polymer-based systems using simple methodologies such as sol-gel, surface modification by means of plasma treatment and blending of chitosan with proteins (soy protein isolate and silk fibroin). A sol-gel method was used to improve the bulk properties of chitosan by the incorporation of an inorganic component at the sub-nanometric level. Chitosan/siloxane hybrid materials were synthesised, where essentially urea bridges covalently bond the chitosan to the polysiloxane network. These bifunctional materials exhibit interesting photoluminescence features and a bioactive behaviour. In most situations in the biomedical field, the surface of a biomaterial is in direct contact with living tissues. Therefore, the surface characteristics play a fundamental role on the implant biocompatibility. In this thesis, nitrogen and argon plasma treatment was applied on chitosan membranes in order to improve their surface properties. The applied modifications promoted differences on surface chemistry, wettability and roughness, which reflected in a significant improvement of fibroblast adhesion and proliferation onto chitosan membranes. Besides the surface modification, blending of chitosan with proteins such as soy protein isolate and silk fibroin was also used to modify the bulk properties of chitosan. In situ cross-linking with glutaraldehyde solutions was

  1. Surface modification and electrochemical behaviour of undoped nanodiamonds

    International Nuclear Information System (INIS)

    Zang Jianbing; Wang Yanhui; Bian Linyan; Zhang Jinhui; Meng Fanwei; Zhao Yuling; Ren Shubin; Qu Xuanhui

    2012-01-01

    Surface modifications of undoped nanodiamond (ND) particles were carried out through different annealing treatments. The methods of Fourier transform infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy were used to characterize the ND surface before and after the annealing process. The electrochemical properties of the modified ND powders in aqueous solution were investigated with Fe(CN) 6 3−/4− as a redox probe. When the annealing temperature was below 850 °C, vacuum annealing removed parts of the oxygen-containing surface functionalities from the ND surface and produced more sp 2 carbon atoms in the shell. The charge transfer of the Fe(CN) 6 3−/4− redox couple decreased with increasing annealing temperature. Re-annealing in air restored the original surface conditions: few sp 2 -bonded carbon atoms and similar surface functionalities, and thus the electrochemical activity. When ND was annealed in vacuum at 900–1100 °C, more serious graphitization produced a continuous fullerenic shell wrapped around a diamond core, which had a high conductivity and electrochemical activity. This provides a novel nanoparticle with high conductivity and high stability for electrochemical applications.

  2. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  3. Modification of the surface energy in isovalent nano-oxides prepared by chemical synthesis

    International Nuclear Information System (INIS)

    Miagava, J.; Gouvea, D.

    2011-01-01

    The phase stability of the nano-oxides depends on the bulk energy but it also depends on the surface energy. The difference of surface energy of the rutile and anatase phases result in a change of phase stability: TiO_2 without additives is stable as anatase when particles have nanometric size and a high specific surface area whereas rutile is stable when particles are larger. But this stability can be modified through the use of additives. Different studies demonstrate that additives segregate on the particle surface modifying the surface energy. In this work (1-X)TiO_2-XSnO_2 powders were synthesized by the polymeric precursor method with concentrations of 0 ≤ X ≤ 1. The specific surface area measurements demonstrate that the modification of the composition change the specific surface areas and it reaches a maximum at X = 0.005. The Raman spectroscopy demonstrates that a modification on the stability of the TiO_2 polymorphs occurs and the phase rutile is stabilized when SnO_2 is added to the nano powders.(author)

  4. Surface modification of an epoxy resin with polyamines and polydopamine: The effect on the initial electroless copper deposition

    Energy Technology Data Exchange (ETDEWEB)

    Schaubroeck, David, E-mail: David.Schaubroeck@elis.ugent.be [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium); Mader, Lothar [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium); De Geyter, Nathalie; Morent, Rino [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Dubruel, Peter [Polymer Chemistry and Biomaterials Research Group, Ghent University, Krijgslaan 281 S4 bis, B-9000 Ghent (Belgium); Vanfleteren, Jan [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium)

    2014-06-01

    This paper describes the influence of polydopamine and polyamine surface modifications of an etched epoxy cresol novolak (ECN) resin on the initial electroless copper deposition. Three different strategies to introduce polyamines on a surface in aqueous environment are applied: via polyethyleneimine adsorption (PEI), via polydopamine and via polyamines grafted to polydopamine. Next, the influence of these surface modifications on the catalytic palladium activation is investigated through X-ray photoelectron spectroscopy (XPS) analysis. Finally, the initial electroless copper deposition on modified epoxy surfaces is evaluated using SEM and Energy Dispersive Spectroscopy (EDS). Grafted polyamines on polydopamine surface modifications result in a large increase of the initial deposited copper.

  5. Laser surface modification of Yttria Stabilized Zirconia (YSZ) thermal barrier coating on AISI H13 tool steel substrate

    Science.gov (United States)

    Reza, M. S.; Aqida, S. N.; Ismail, I.

    2018-03-01

    This paper presents laser surface modification of plasma sprayed yttria stabilized zirconia (YSZ) coating to seal porosity defect. Laser surface modification on plasma sprayed YSZ was conducted using 300W JK300HPS Nd: YAG laser at different operating parameters. Parameters varied were laser power and pulse frequency with constant residence time. The coating thickness was measured using IM7000 inverted optical microscope and surface roughness was analysed using two-dimensional Mitutoyo Surface Roughness Tester. Surface roughness of laser surface modification of YSZ H-13 tool steel decreased significantly with increasing laser power and decreasing pulse frequency. The re-melted YSZ coating showed higher hardness properties compared to as-sprayed coating surface. These findings were significant to enhance thermal barrier coating surface integrity for dies in semi-solid processing.

  6. [Surface grafting modification and stabilization of Kevlar fiber].

    Science.gov (United States)

    Zheng, Yu-ying; Fu, Ming-lian; Wang, Can-yao; Wang, Liang-en

    2005-11-01

    Chemical disposal was used to bring the activity group onto the surface of Kevlar fiber for the purpose of surface grafting modification. The interfacial constitution of the grafting of toluene-2,4-diisocyanate (TDI) onto Kevlar fiber was determined by Fourier transform infrared spectroscopy. In the mean time, hexyl-lactam stabilization and poly-glycol (400, PEG) stabilization on the grafted product were also studied. The effects of different nTDI:nPEG ratios on the production's interfacial constitution was analysed. It is concluded that the stabilization took place on the surface. The intensity of the bands relented at about 3300 cm(-1) and was reinforced at about 1700-1720 cm(-1) when the ratio of nTDI:nPEG = 1:3, but when the ratio is 1:1 and 1:2, the bands at about 3 300 and 1700-1720 cm(-1) are almost the same.

  7. Development of advanced coatings for laser modifications through process and materials simulation

    International Nuclear Information System (INIS)

    Martukanitz, R.P.; Babu, S.S.

    2004-01-01

    A simulation-based system is currently being constructed to aid in the development of advanced coating systems for laser cladding and surface alloying. The system employs loosely coupled material and process models that allow rapid determination of material compatibility over a wide range of processing conditions. The primary emphasis is on the development and identification of composite coatings for improved wear and corrosion resistance. The material model utilizes computational thermodynamics and kinetic analysis to establish phase stability and extent of diffusional reactions that may result from the thermal response of the material during virtual processing. The process model is used to develop accurate thermal histories associated with the laser surface modification process and provides critical input for the non-isothermal materials simulations. These techniques were utilized to design a laser surface modification experiment that utilized the addition of stainless steel alloy 431 and TiC produced using argon and argon and nitrogen shielding. The deposits representing alloy 431 and TiC powder produced in argon resulted in microstructures retaining some TiC particles and an increase in hardness when compared to deposits produced using only the 431 powder. Laser deposits representing alloy 431 and TiC powder produced with a mixture of argon and nitrogen shielding gas resulted in microstructures retaining some TiC particles, as well as fine precipitates of Ti(CN) formed during cooling and a further increase in hardness of the deposit

  8. UV Light Induced Surface Modification of HDPE Films with Bioactive Compounds

    Czech Academy of Sciences Publication Activity Database

    Daniloska, V.; Blazevska-Gilev, J.; Dimova, V.; Fajgar, Radek; Tomovska, R.

    2010-01-01

    Roč. 256, č. 7 (2010), s. 2276-2283 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z40720504 Keywords : surface modification * uv irradiation * benzocaine Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.795, year: 2010

  9. Carbon ion irradiation induced surface modification of polypropylene

    International Nuclear Information System (INIS)

    Saha, A.; Chakraborty, V.; Dutta, R.K.; Chintalapudi, S.N.

    2001-01-01

    Polypropylene was irradiated with 12 C ions of 3.6 and 5.4 MeV energies in the fluence range of 5x10 13 -5x10 14 ions/cm 2 using 3 MV tandem accelerator. Ion penetration was limited to a few microns and surface modifications were investigated by scanning electron microscopy. At the lowest ion fluence only blister formation of various sizes (1-6 μm) were observed, but at higher fluence (1x10 14 ions/cm 2 ) a three-dimensional network structure was found to form. A gradual degradation in the network structure was observed with further increase in the ion fluence. The dose dependence of the changes on surface morphology of polypropylene is discussed

  10. Carbon ion irradiation induced surface modification of polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Saha, A. E-mail: abhijit@alpha.iuc.res.in; Chakraborty, V.; Dutta, R.K.; Chintalapudi, S.N

    2001-12-01

    Polypropylene was irradiated with {sup 12}C ions of 3.6 and 5.4 MeV energies in the fluence range of 5x10{sup 13}-5x10{sup 14} ions/cm{sup 2} using 3 MV tandem accelerator. Ion penetration was limited to a few microns and surface modifications were investigated by scanning electron microscopy. At the lowest ion fluence only blister formation of various sizes (1-6 {mu}m) were observed, but at higher fluence (1x10{sup 14} ions/cm{sup 2}) a three-dimensional network structure was found to form. A gradual degradation in the network structure was observed with further increase in the ion fluence. The dose dependence of the changes on surface morphology of polypropylene is discussed.

  11. New electron-ion-plasma equipment for modification of materials and products surface

    International Nuclear Information System (INIS)

    Koval', N.N.

    2013-01-01

    Electron-ion-plasma treatment of materials and products, including surface clearing and activation, formation surface layers with changed chemical and phase structure, increased hardness and corrosion resistance; deposition of various functional coatings, has received a wide distribution in a science and industry. Widespread methods of ion-plasma modification of material and product surfaces are ion etching and activation, ion-plasma nitriding, arc or magnetron deposition of functional coatings, including nanostructured. The combination of above methods of surface modification allows essentially to improve exploitation properties of treated products and to optimize the characteristics of modified surfaces for concrete final requirements. For the purpose of a combination of various methods of ion-plasma treatment in a single work cycle at Institute of High Current Electronics of SB RAS (IHCE SB RAS) specialized technological equipment 'DUET', 'TRIO' and 'QUADRO' and 'KVINTA' have been developed. This equipment allow generating uniform low-temperature gas plasma at pressures of (0.1-1) Pa with concentration of (10 9 -10 11 ) cm -3 in volume of (0.1-1) m 3 . In the installations consistent realization of several various operations of materials and products treatment in a single work cycle is possible. The operations are preliminary heating and degassing, ion clearing, etching and activation of materials and products surface by plasma of arc discharges; chemicothermal treatment (nitriding) for formation of diffusion layer on a surface of treated sample using plasma of nonself-sustained low-pressure arc discharge; deposition of single- or multilayered superhard (≥40 GPa) nanocrystalline coatings on the basis of pure metals or their compounds (nitrides, carbides, carbonitrides) by the arc plasma-assisted method. For realization of the modes all installations are equipped by original sources of gas and metal plasma. Besides, in

  12. Surface Modification of MXenes: A Pathway to Improve MXene Electrode Performance in Electrochemical Energy Storage Devices

    KAUST Repository

    Ahmed, Bilal

    2017-12-31

    The recent discovery of layered transition metal carbides (MXenes) is one of the most important developments in two-dimensional (2D) materials. Preliminary theoretical and experimental studies suggest a wide range of potential applications for MXenes. The MXenes are prepared by chemically etching ‘A’-layer element from layered ternary metal carbides, nitrides and carbonitrides (MAX phases) through aqueous acid treatment, which results in various surface terminations such as hydroxyl, oxygen or fluorine. It has been found that surface terminations play a critical role in defining MXene properties and affects MXene performance in different applications such as electrochemical energy storage, electromagnetic interference shielding, water purification, sensors and catalysis. Also, the electronic, thermoelectric, structural, plasmonic and optical properties of MXenes largely depend upon surface terminations. Thus, controlling the surface chemistry if MXenes can be an efficient way to improve their properties. This research mainly aims to perform surface modifications of two commonly studied MXenes; Ti2C and Ti3C2, via chemical, thermal or physical processes to enhance electrochemical energy storage properties. The as-prepared and surface modified MXenes have been studied as electrode materials in Li-ion batteries (LIBs) and supercapacitors (SCs). In pursuit of desirable MXene surface, we have developed an in-situ room temperature oxidation process, which resulted in TiO2/MXene nanocomposite and enhanced Li-ion storage. The idea of making metal oxide and MXene nanocomposites was taken to the next level by combining a high capacity anode materials – SnO2 – and MXene. By taking advantage of already existing surface functional groups (–OH), we have developed a composite of SnO2/MXene by atomic layer deposition (ALD) which showed enhanced capacity and excellent cyclic stability. Thermal annealing of MXene at elevated temperature under different atmospheres was

  13. Surface modification of poly(D,L-lactic acid) scaffolds for orthopedic applications: a biocompatible, nondestructive route via diazonium chemistry.

    Science.gov (United States)

    Mahjoubi, Hesameddin; Kinsella, Joseph M; Murshed, Monzur; Cerruti, Marta

    2014-07-09

    Scaffolds made with synthetic polymers such as polyesters are commonly used in bone tissue engineering. However, their hydrophobicity and the lack of specific functionalities make their surface not ideal for cell adhesion and growth. Surface modification of these materials is thus crucial to enhance the scaffold's integration in the body. Different surface modification techniques have been developed to improve scaffold biocompatibility. Here we show that diazonium chemistry can be used to modify the outer and inner surfaces of three-dimensional poly(D,L-lactic acid) (PDLLA) scaffolds with phosphonate groups, using a simple two-step method. By changing reaction time and impregnation procedure, we were able to tune the concentration of phosphonate groups present on the scaffolds, without degrading the PDLLA matrix. To test the effectiveness of this modification, we immersed the scaffolds in simulated body fluid, and characterized them with scanning electron microscopy, X-ray photoelectron spectroscopy, Raman, and infrared spectroscopy. Our results showed that a layer of hydroxyapatite particles was formed on all scaffolds after 2 and 4 weeks of immersion; however, the precipitation was faster and in larger amounts on the phosphonate-modified than on the bare PDLLA scaffolds. Both osteogenic MC3T3-E1 and chondrogenic ATDC5 cell lines showed increased cell viability/metabolic activity when grown on a phosphonated PDLLA surface in comparison to a control PDLLA surface. Also, more calcium-containing minerals were deposited by cultures grown on phosphonated PDLLA, thus showing the pro-mineralization properties of the proposed modification. This work introduces diazonium chemistry as a simple and biocompatible technique to modify scaffold surfaces, allowing to covalently and homogeneously bind a number of functional groups without degrading the scaffold's polymeric matrix.

  14. Multifunctional surface modification of silk fabric via graphene oxide repeatedly coating and chemical reduction method

    Science.gov (United States)

    Cao, Jiliang; Wang, Chaoxia

    2017-05-01

    Multifunctional silk fabrics with electrical conductive, anti-ultraviolet and water repellent were successfully prepared by surface modification with graphene oxide (GO). The yellow-brown GO deposited on the surface of silk fabric was converted into graphitic black reduced graphene (RGO) by sodium hydrosulfite. The surface properties of silk fabrics were changed by repeatedly RGO coating process, which have been proved by SEM and XPS. The SEM results showed that the RGO sheets were successive form a continuously thin film on the surface of silk fabrics, and the deposition of GO or RGO also can be proved by XPS. The electrical conductivity was tested by electrical surface resistance value of the silk fabric, the surface resistance decreased with increasing of RGO surface modification times, and a low surface resistance value reached to 3.24 KΩ cm-1 after 9 times of modification, indicating the silk obtained excellent conductivity. The UPF value of one time GO modification silk fabric (silk-1RGO) was enhanced significantly to 24.45 in comparison to 10.40 of original silk. The contact angle of RGO coating silk samples was all above of 120°. The durability of RGO coated silk fabrics was tested by laundering. The electrical surface resistance of silk-4RGO (65.74 KΩ cm-1), silk-6RGO (15.54 KΩ cm-1) and silk-8RGO (3.86 KΩ cm-1) fabrics was up to 86.82, 22.30 and 6.57 KΩ cm-1 after 10 times of standard washing, respectively. The UPF value, contact angle and color differences of RGO modified silk fabric slightly changed before and after 10 times of standard washing. Therefore, the washing fastness of electric conduction, anti-ultraviolet and water repellent multifunctional silk fabrics was excellent.

  15. Drag reduction in reservoir rock surface: Hydrophobic modification by SiO_2 nanofluids

    International Nuclear Information System (INIS)

    Yan, Yong-Li; Cui, Ming-Yue; Jiang, Wei-Dong; He, An-Le; Liang, Chong

    2017-01-01

    Graphical abstract: The micro-nanoscale hierarchical structures at the sandstone core surface are constructed by adsorption of the modified silica nanoparticles, which leads to the effect of drag reduction to improve the low injection rate in ultra-low permeability reservoirs. - Highlights: • A micro-nanoscale hierarchical structure is formed at the reservoir rock surface. • An inversion has happened from hydrophilic into hydrophobic modified by nanofluids. • The effect of drag reduction to improve the low injection rate is realized. • The mechanism of drag reduction induced from the modified core surface was unclosed. - Abstract: Based on the adsorption behavior of modified silica nanoparticles in the sandstone core surface, the hydrophobic surface was constructed, which consists of micro-nanoscale hierarchical structure. This modified core surface presents a property of drag reduction and meets the challenge of high injection pressure and low injection rate in low or ultra-low permeability reservoir. The modification effects on the surface of silica nanoparticles and reservoir cores, mainly concerning hydrophobicity and fine structure, were determined by measurements of contact angle and scanning electron microscopy. Experimental results indicate that after successful modification, the contact angle of silica nanoparticles varies from 19.5° to 141.7°, exhibiting remarkable hydrophobic properties. These modified hydrophobic silica nanoparticles display a good adsorption behavior at the core surface to form micro-nanobinary structure. As for the wettability of these modified core surfaces, a reversal has happened from hydrophilic into hydrophobic and its contact angle increases from 59.1° to 105.9°. The core displacement experiments show that the relative permeability for water has significantly increased by an average of 40.3% via core surface modification, with the effects of reducing injection pressure and improving injection performance of water

  16. Surface modification of the metal plates using continuous electron beam process (CEBP)

    International Nuclear Information System (INIS)

    Kim, Jisoo; Kim, Jin-Seok; Kang, Eun-Goo; Park, Hyung Wook

    2014-01-01

    Highlights: • We performed surface modification of SM20C, SUS303, and Al6061 using CEBP. • We analyzed surface properties and microstructure after electron-beam irradiation. • The surface quality was improved after electron-beam irradiation. • The surface hardness for SM20C was increased by ∼50% after CEBP irradiation. - Abstract: The finishing process is an important component of the quality-control procedure for final products in manufacturing applications. In this study, we evaluated the performance of continuous electron-beam process as the final process for finishing SM20C (steel alloy), SUS303 (stainless steel alloy), and Al6061 (aluminum alloy) surfaces both on the initially smooth and rough surfaces. Surface modification of the metals was carried out by varying the feed and frequency of the continuous electron-beam irradiation procedure. The resulting surface roughness was examined with respect to the initial surface roughness of the metals. SM20C and SUS303 experienced an improvement in surface roughness, particularly for initially rough surfaces. Continuous electron-beam process produced craters during the process and the effect of this phenomenon on the resulting surface roughness was relatively large with the initially smooth SM20C and SUS303 alloy surfaces. For Al6061, the continuous electron-beam process was effective at improving its surface roughness even with the initially smooth surface under the optimized conditions of process; this was attributed to its low melting point. Scanning electron microscopy was used to identify metallurgical variation within the thin melted and re-solidification layers of the tested alloys. Changes in the surface contact angle and hardness before and after electron-beam irradiation were also examined

  17. Surface modification of the metal plates using continuous electron beam process (CEBP)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jisoo, E-mail: kimjisu16@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Kim, Jin-Seok, E-mail: totoro22@kitech.re.kr [Korea Institute of Industrial Technology (KITECH), KITECH Cheonan Headquarters 35-3 Hongcheon-ri, Ipjang-myeon, Cheonan-si, Chungcheongnam-do 330-825 (Korea, Republic of); Kang, Eun-Goo, E-mail: egkang@kitech.re.kr [Korea Institute of Industrial Technology (KITECH), KITECH Cheonan Headquarters 35-3 Hongcheon-ri, Ipjang-myeon, Cheonan-si, Chungcheongnam-do 330-825 (Korea, Republic of); Park, Hyung Wook, E-mail: hwpark@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of)

    2014-08-30

    Highlights: • We performed surface modification of SM20C, SUS303, and Al6061 using CEBP. • We analyzed surface properties and microstructure after electron-beam irradiation. • The surface quality was improved after electron-beam irradiation. • The surface hardness for SM20C was increased by ∼50% after CEBP irradiation. - Abstract: The finishing process is an important component of the quality-control procedure for final products in manufacturing applications. In this study, we evaluated the performance of continuous electron-beam process as the final process for finishing SM20C (steel alloy), SUS303 (stainless steel alloy), and Al6061 (aluminum alloy) surfaces both on the initially smooth and rough surfaces. Surface modification of the metals was carried out by varying the feed and frequency of the continuous electron-beam irradiation procedure. The resulting surface roughness was examined with respect to the initial surface roughness of the metals. SM20C and SUS303 experienced an improvement in surface roughness, particularly for initially rough surfaces. Continuous electron-beam process produced craters during the process and the effect of this phenomenon on the resulting surface roughness was relatively large with the initially smooth SM20C and SUS303 alloy surfaces. For Al6061, the continuous electron-beam process was effective at improving its surface roughness even with the initially smooth surface under the optimized conditions of process; this was attributed to its low melting point. Scanning electron microscopy was used to identify metallurgical variation within the thin melted and re-solidification layers of the tested alloys. Changes in the surface contact angle and hardness before and after electron-beam irradiation were also examined.

  18. A low-cost, high-efficiency and high-flexibility surface modification technology for a black bisphenol A polycarbonate board

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Suhuan; Liu, Jianguo, E-mail: Liujg@mail.hust.edu.cn; Lv, Ming; Zeng, Xiaoyan

    2014-09-30

    Highlights: • A low-cost, high-efficiency, high-flexibility surface modification technology was achieved. • Different laser modification parameters resulted in different surface microstructures. • These special microstructures played a deciding role in the surface properties. • After the modification, the surface energy was found to have a significant increase. • The technology would be advantageous to fabricate high-quality micro devices and systems. - Abstract: In this paper, a low-cost, high-efficiency and high-flexibility surface modification technology for polymer materials was achieved at high laser scanning speeds (600–1000 mm s{sup −1}) and using an all-solid state, Q-switched, high-average power, and nanosecond pulse ultraviolet (355 nm wavelength) laser. During the surface modification of a very important engineering plastic, i.e., black bisphenol A polycarbonate (BAPC) board, it was found that different laser parameters (e.g., laser fluence and pulse frequency) were able to result in different surface microstructures (e.g., many tiny protuberances or a porous microstructure with periodical V-type grooves). After the modification, although the total relative content of the oxygen-containing groups (e.g., C-O and COO{sup −}) on the BAPC surface increased, however, the special microstructures played a deciding role in the surface properties (e.g., contact angle and surface energy) of the BAPC. The change trend of the water contact angle on the BAPC surface was with an obvious increase, that of the diiodomethane contact angle was with a most decrease, and that of the ethylene glycol contact angle was between the above two. It showed that the wetting properties of the three liquids on the modified BAPC surface were different. Basing on the measurements of the contact angles of the three liquids, and according to the Young equation and the Lifshitz van der Waals and Lewis acid–base theory, the BAPC surface energy after the modification was

  19. A low-cost, high-efficiency and high-flexibility surface modification technology for a black bisphenol A polycarbonate board

    International Nuclear Information System (INIS)

    Wang, Suhuan; Liu, Jianguo; Lv, Ming; Zeng, Xiaoyan

    2014-01-01

    Highlights: • A low-cost, high-efficiency, high-flexibility surface modification technology was achieved. • Different laser modification parameters resulted in different surface microstructures. • These special microstructures played a deciding role in the surface properties. • After the modification, the surface energy was found to have a significant increase. • The technology would be advantageous to fabricate high-quality micro devices and systems. - Abstract: In this paper, a low-cost, high-efficiency and high-flexibility surface modification technology for polymer materials was achieved at high laser scanning speeds (600–1000 mm s −1 ) and using an all-solid state, Q-switched, high-average power, and nanosecond pulse ultraviolet (355 nm wavelength) laser. During the surface modification of a very important engineering plastic, i.e., black bisphenol A polycarbonate (BAPC) board, it was found that different laser parameters (e.g., laser fluence and pulse frequency) were able to result in different surface microstructures (e.g., many tiny protuberances or a porous microstructure with periodical V-type grooves). After the modification, although the total relative content of the oxygen-containing groups (e.g., C-O and COO − ) on the BAPC surface increased, however, the special microstructures played a deciding role in the surface properties (e.g., contact angle and surface energy) of the BAPC. The change trend of the water contact angle on the BAPC surface was with an obvious increase, that of the diiodomethane contact angle was with a most decrease, and that of the ethylene glycol contact angle was between the above two. It showed that the wetting properties of the three liquids on the modified BAPC surface were different. Basing on the measurements of the contact angles of the three liquids, and according to the Young equation and the Lifshitz van der Waals and Lewis acid–base theory, the BAPC surface energy after the modification was calculated

  20. Surface modification of nanodiamond through metal free atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Guangjian; Liu, Meiying; Shi, Kexin; Heng, Chunning; Mao, Liucheng; Wan, Qing; Huang, Hongye [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Deng, Fengjie, E-mail: fengjiedeng@aliyun.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wei, Yen, E-mail: weiyen@tsinghua.edu.cn [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

    2016-12-30

    Highlights: • Surface modification of ND with water soluble and biocompatible polymers. • Functionalized ND through metal free surface initiated ATRP. • The metal free surface initiated ATRP is rather simple and effective. • The ND-poly(MPC) showed high dispersibility and desirable biocompatibility. - Abstract: Surface modification of nanodiamond (ND) with poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] has been achieved by using metal free surface initiated atom transfer radical polymerization (SI-ATRP). The ATRP initiator was first immobilized on the surface of ND through direct esterification reaction between hydroxyl group of ND and 2-bromoisobutyryl bromide. The initiator could be employed to obtain ND-poly(MPC) nanocomposites through SI-ATRP using an organic catalyst. The final functional materials were characterized by {sup 1}H nuclear magnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermo gravimetric analysis in detailed. All of these characterization results demonstrated that ND-poly(MPC) have been successfully obtained via metal free photo-initiated SI-ATRP. The ND-poly(MPC) nanocomposites shown enhanced dispersibility in various solvents as well as excellent biocompatibility. As compared with traditional ATRP, the metal free ATRP is rather simple and effective. More importantly, this preparation method avoided the negative influence of metal catalysts. Therefore, the method described in this work should be a promising strategy for fabrication of polymeric nanocomposites with great potential for different applications especially in biomedical fields.

  1. Surface modification of nanodiamond through metal free atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Zeng, Guangjian; Liu, Meiying; Shi, Kexin; Heng, Chunning; Mao, Liucheng; Wan, Qing; Huang, Hongye; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2016-01-01

    Highlights: • Surface modification of ND with water soluble and biocompatible polymers. • Functionalized ND through metal free surface initiated ATRP. • The metal free surface initiated ATRP is rather simple and effective. • The ND-poly(MPC) showed high dispersibility and desirable biocompatibility. - Abstract: Surface modification of nanodiamond (ND) with poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] has been achieved by using metal free surface initiated atom transfer radical polymerization (SI-ATRP). The ATRP initiator was first immobilized on the surface of ND through direct esterification reaction between hydroxyl group of ND and 2-bromoisobutyryl bromide. The initiator could be employed to obtain ND-poly(MPC) nanocomposites through SI-ATRP using an organic catalyst. The final functional materials were characterized by 1 H nuclear magnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermo gravimetric analysis in detailed. All of these characterization results demonstrated that ND-poly(MPC) have been successfully obtained via metal free photo-initiated SI-ATRP. The ND-poly(MPC) nanocomposites shown enhanced dispersibility in various solvents as well as excellent biocompatibility. As compared with traditional ATRP, the metal free ATRP is rather simple and effective. More importantly, this preparation method avoided the negative influence of metal catalysts. Therefore, the method described in this work should be a promising strategy for fabrication of polymeric nanocomposites with great potential for different applications especially in biomedical fields.

  2. Graphite anode surface modification with controlled reduction of specific aryl diazonium salts for improved microbial fuel cells power output.

    Science.gov (United States)

    Picot, Matthieu; Lapinsonnière, Laure; Rothballer, Michael; Barrière, Frédéric

    2011-10-15

    Graphite electrodes were modified with reduction of aryl diazonium salts and implemented as anodes in microbial fuel cells. First, reduction of 4-aminophenyl diazonium is considered using increased coulombic charge density from 16.5 to 200 mC/cm(2). This procedure introduced aryl amine functionalities at the surface which are neutral at neutral pH. These electrodes were implemented as anodes in "H" type microbial fuel cells inoculated with waste water, acetate as the substrate and using ferricyanide reduction at the cathode and a 1000 Ω external resistance. When the microbial anode had developed, the performances of the microbial fuel cells were measured under acetate saturation conditions and compared with those of control microbial fuel cells having an unmodified graphite anode. We found that the maximum power density of microbial fuel cell first increased as a function of the extent of modification, reaching an optimum after which it decreased for higher degree of surface modification, becoming even less performing than the control microbial fuel cell. Then, the effect of the introduction of charged groups at the surface was investigated at a low degree of surface modification. It was found that negatively charged groups at the surface (carboxylate) decreased microbial fuel cell power output while the introduction of positively charged groups doubled the power output. Scanning electron microscopy revealed that the microbial anode modified with positively charged groups was covered by a dense and homogeneous biofilm. Fluorescence in situ hybridization analyses showed that this biofilm consisted to a large extent of bacteria from the known electroactive Geobacter genus. In summary, the extent of modification of the anode was found to be critical for the microbial fuel cell performance. The nature of the chemical group introduced at the electrode surface was also found to significantly affect the performance of the microbial fuel cells. The method used for

  3. Surface modification of carbon nanotubes via combination of mussel inspired chemistry and chain transfer free radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Qing; Tian, Jianwen; Liu, Meiying; Zeng, Guangjian; Huang, Qiang [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wang, Ke; Zhang, Qingsong [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China); Deng, Fengjie, E-mail: fengjiedeng@aliyun.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wei, Yen, E-mail: weiyen@tsinghua.edu.cn [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

    2015-08-15

    Graphical abstract: A novel strategy combination of mussel inspired chemistry and chain transfer free radical polymerization has been developed for surface modification of carbon nanotubes with polymers for the first time. - Highlights: • Surface modification of CNTs via mussel inspired chemistry. • Preparation of aminated polymers through free radical polymerization. • Functionalized CNTs with aminated polymers via Michael addition reaction. • Highly dispersed CNTs in organic and aqueous solution. - Abstract: In this work, a novel strategy for surface modification of carbon nanotubes (CNTs) was developed via combination of mussel inspired chemistry and chain transfer free radical polymerization. First, pristine CNTs were functionalized with polydopamine (PDA), which is formed via self-polymerization of dopamine in alkaline conditions. These PDA functionalized CNTs can be further reacted with amino-terminated polymers (named as PDMC), which was synthesized through chain transfer free radical polymerization using cysteamine hydrochloride as chain transfer agent and methacryloxyethyltrimethyl ammonium chloride as the monomer. PDMC perfectly conjugated with CNT-PDA was ascertained by a series of characterization techniques including transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The dispersibility of obtained CNT nanocomposites (named as CNT-PDA-PDMC) was further examined. Results showed that the dispersibility of CNT-PDA-PDMC in aqueous and organic solutions was obviously enhanced. Apart from PDMC, many other amino-terminated polymers can also be used to functionalization of CNTs via similar strategy. Therefore, the method described in this work should be a general strategy for fabrication various polymer nanocomposites.

  4. Surface-defect induced modifications in the optical properties of α-MnO_2 nanorods

    International Nuclear Information System (INIS)

    John, Reenu Elizabeth; Chandran, Anoop; Thomas, Marykutty; Jose, Joshy; George, K.C.

    2016-01-01

    Graphical abstract: - Highlights: • Alpha-MnO_2 nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO_2 nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO_6 octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn"3"+) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO_2. These studies suggest that

  5. Surface modification of ceramic and metallic alloy substrates by laser raster-scanning

    Science.gov (United States)

    Ramos Grez, Jorge Andres

    This work describes the feasibility of continuous wave laser-raster scan-processing under controlled atmospheric conditions as employed in three distinct surface modification processes: (a) surface roughness reduction of indirect-Selective Laser Sintered 420 martensitic stainless steel-40 wt. % bronze infiltrated surfaces; (b) Si-Cr-Hf-C coating consolidation over 3D carbon-carbon composites cylinders; (c) dendritic solidification structures of Mar-M 247 confined powder precursor grown from polycrystalline Alloy 718 substrates. A heat transfer model was developed to illustrate that the aspect ratio of the laser scanned pattern and the density of scanning lines play a significant role in determining peak surface temperature, heating and cooling rates and melt resident times. Comprehensive characterization of the surface of the processed specimens was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), optical metallography, X-ray diffraction (XRD), and, in certain cases, tactile profilometry. In Process (a), it was observed that a 24% to 37% roughness Ra reduction could be accomplished from the as-received value of 2.50+/-0.10 microns for laser energy densities ranging from 350 to 500 J/cm2. In Process (b), complete reactive wetting of carbon-carbon composite cylinders surface was achieved by laser melting a Si-Cr-Hf-C slurry. Coatings showed good thermal stability at 1000°C in argon, and, when tested in air, a percent weight reduction rate of -6.5 wt.%/hr was achieved. A soda-glass overcoat applied over the coated specimens by conventional means revealed a percent weight reduction rate between -1.4 to -2.2 wt.%/hr. Finally, in Process (c), microstructure of the Mar-M 247 single layer deposits, 1 mm in height, grown on Alloy 718 polycrystalline sheets, resulted in a sound metallurgical bond, low porosity, and uniform thickness. Polycrystalline dendrites grew preferentially along the [001] direction from the substrate up to 400

  6. Surface Modification of Polymeric Materials by Plasma Treatment

    Directory of Open Access Journals (Sweden)

    E.F. Castro Vidaurre

    2002-03-01

    Full Text Available Low-temperature plasma treatment has been used in the last years as a useful tool to modify the surface properties of different materials, in special of polymers. In the present work low temperature plasma was used to treat the surface of asymmetric porous substrates of polysulfone (PSf membranes. The main purpose of this work was to study the influence of the exposure time and the power supplied to argon plasma on the permeability properties of the membranes. Three rf power levels, respectively 5, 10 and 15 W were used. Treatment time ranged from 1 to 50 min. Reduction of single gas permeability was observed with Ar plasma treatments at low energy bombardment (5 W and short exposure time (20 min. Higher power and/or higher plasma exposition time causes a degradation process begins. The chemical and structural characterization of the membranes before and after the surface modification was done by AFM, SEM and XPS.

  7. Modification of the surfaces of medical devices to prevent microbial adhesion and biofilm formation.

    Science.gov (United States)

    Desrousseaux, C; Sautou, V; Descamps, S; Traoré, O

    2013-10-01

    The development of devices with surfaces that have an effect against microbial adhesion or viability is a promising approach to the prevention of device-related infections. To review the strategies used to design devices with surfaces able to limit microbial adhesion and/or growth. A PubMed search of the published literature. One strategy is to design medical devices with a biocidal agent. Biocides can be incorporated into the materials or coated or covalently bonded, resulting either in release of the biocide or in contact killing without release of the biocide. The use of biocides in medical devices is debated because of the risk of bacterial resistance and potential toxicity. Another strategy is to modify the chemical or physical surface properties of the materials to prevent microbial adhesion, a complex phenomenon that also depends directly on microbial biological structure and the environment. Anti-adhesive chemical surface modifications mostly target the hydrophobicity features of the materials. Topographical modifications are focused on roughness and nanostructures, whose size and spatial organization are controlled. The most effective physical parameters to reduce bacterial adhesion remain to be determined and could depend on shape and other bacterial characteristics. A prevention strategy based on reducing microbial attachment rather than on releasing a biocide is promising. Evidence of the clinical efficacy of these surface-modified devices is lacking. Additional studies are needed to determine which physical features have the greatest potential for reducing adhesion and to assess the usefulness of antimicrobial coatings other than antibiotics. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  8. Surface modification of multilayer graphene using Ga ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Quan, E-mail: wangq@mail.ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shao, Ying; Ge, Daohan; Ren, Naifei [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yang, Qizhi [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State key laboratory of Robotics, Chinese Academy of Sciences, Shengyang 110000 (China)

    2015-04-28

    The effect of Ga ion irradiation intensity on the surface of multilayer graphene was examined. Using Raman spectroscopy, we determined that the irradiation caused defects in the crystal structure of graphene. The density of defects increased with the increase in dwell times. Furthermore, the strain induced by the irradiation changed the crystallite size and the distance between defects. These defects had the effect of doping the multilayer graphene and increasing its work function. The increase in work function was determined using contact potential difference measurements. The surface morphology of the multilayer graphene changed following irradiation as determined by atomic force microscopy. Additionally, the adhesion between the atomic force microscopy tip and sample increased further indicating that the irradiation had caused surface modification, important for devices that incorporate graphene.

  9. Enhanced osteointegration of medical titanium implant with surface modifications in micro/nanoscale structures

    OpenAIRE

    Lin, Liwen; Wang, Hui; Ni, Ming; Rui, Yunfeng; Cheng, Tian-Yuan; Cheng, Cheng-Kung; Pan, Xiaohua; Li, Gang; Lin, Changjian

    2014-01-01

    Biomimetic design and substrate-based surface modification of medical implants will help to improve the integration of tissue to its material interfaces. Surface energy, composition, roughness, and topography all influence the biological responses of the implants, such as protein adsorption and cell adhesion, proliferation and differentiation. In the current study, different surface structures of Ti implants were constructed using facile surface techniques to create various micro-, nano-, and...

  10. Surface Modification for Improved Design and Functionality of Nanostructured Materials and Devices

    Science.gov (United States)

    Keiper, Timothy Keiper

    Progress in nanotechnology is trending towards applications which require the integration of soft (organic or biological) and hard (semiconductor or metallic) materials. Many applications for functional nanomaterials are currently being explored, including chemical and biological sensors, flexible electronics, molecular electronics, etc., with researchers aiming to develop new paradigms of nanoelectronics through manipulation of the physical properties by surface treatments. This dissertation focuses on two surface modification techniques important for integration of hard and soft materials: thermal annealing and molecular modification of semiconductors. First, the effects of thermal annealing are investigated directly for their implication in the fundamental understanding of transparent conducting oxides with respect to low resistivity contacts for electronic and optoelectronic applications and the response to environmental stimuli for sensing applications. The second focus of this dissertation covers two aspects of the importance of molecular modification on semiconductor systems. The first of these is the formation of self-assembled monolayers in patterned arrays which leads explicitly to the directed self-assembly of nanostructures. The second aspect concerns the modification of the underlying magnetic properties of the preeminent dilute magnetic semiconductor, manganese-doped gallium arsenide. Tin oxide belongs to a class of materials known as transparent conducting oxides which have received extensive interest due to their sensitivity to environmental stimuli and their potential application in transparent and flexible electronics. Nanostructures composed of SnO2 have been demonstrated as an advantageous material for high performance, point-of-care nanoelectronic sensors, capable of detecting and distinguishing gaseous or biomolecular interactions on unprecedented fast timescales. Through bottom-up fabrication techniques, binary oxide nanobelts synthesized

  11. The effect of substrate modification on microbial growth on surfaces

    International Nuclear Information System (INIS)

    Brown, Angela Ann

    1998-01-01

    The principle aim of the program was to produce a novel, non-leaching antimicrobial surface for commercial development and future use in the liquid food packaging industry. Antimicrobial surfaces which exist presently have been produced to combat the growth of prokaryotic organisms and usually function as slow release systems. A system which could inhibit eukaryotic growth without contaminating the surrounding 'environment' with the inhibitor was considered of great commercial importance. The remit of this study was concerned with creating a surface which could control the growth of eukaryotic organisms found in fruit juice with particular interest in the yeast, Saccharomyces cerevisiae. Putative antimicrobial surfaces were created by the chemical modification of the test substrate polymers; nylon and ethylvinyl alcohol (EVOH). Surfaces were chemically modified by the covalent coupling of antimicrobial agents known to be active against the yeast Saccharomyces cerevisiae as ascertained by the screening process determining the minimum inhibitory concentration (MIC) values of agents in the desired test medium. During the study it was found that a number of surfaces did appear to inhibit yeast growth in fruit juice, however on further investigation the apparent inhibitory effect was discovered to be the result of un-bound material free in the test medium. On removing the possibility of any un-bound material present on the test surface, by a series of surface washings, the inhibitory effect on yeast growth was eliminated. Of the agents tested only one appeared to have an inhibitory effect which could be attributed to a true antimicrobial surface effect, Amical 48. As there is little known about this agent in the literature, its affect on yeast growth was examined and in particular a proposal for the mode of action on yeast is discussed, providing a plausible explanation for the inhibitory effect observed when this agent is covalently immobilised onto nylon. (author)

  12. Review of some research work on surface modification and polymerizations by non-equilibrium plasma in Turkey

    International Nuclear Information System (INIS)

    Akovali, Guneri

    2004-01-01

    Non equilibrium plasma studies in Turkey can be considered as organized on two different lines: surface modification studies and plasma polymerization studies. Plasma surface modification studies: In different laboratories in Turkey the modification of materials' surfaces by plasma covers a wide spectra, for example: fibers (Carbon (CF) and polyacrylonitrile (PAN)), fabrics (PET/Cotton and PET/PA), biomaterials-food oriented (PU), denture Acrylic matrix, plasmochemical modification of a (PE and PP) film surface by several selected silicon and tin containing monomers, polymer blends and composites, recycled rubber and epoxy systems, etc. Plasma polymerization studies: This topic is accomplished by a great number of projects, for instance: plasma initiation polymerization and copolymerization of Styrene and MMA, Plasma-initiated polymerizations of Acrylamide (AA), kinetics of polymer deposition of several selected saturated hydrocarbons, silanization treatments by hexamethyldisilazane (HDMS), Plasma initiated polymerization (PIP) of allyl alcohol and 1-propano, (PSP) and (PIP) studies related to activated charcoal are done to explore their applications in haemoperfusion, an amperometric alcohol single-layer electrode is prepared by (EDA) plasma polymerization, preparation of mass sensitive immuno sensors and single layer multi enzyme electrodes by plasma polymerisation technique, etc

  13. Facile surface modification of silicone rubber with zwitterionic polymers for improving blood compatibility

    International Nuclear Information System (INIS)

    Liu, Pingsheng; Chen, Qiang; Yuan, Bo; Chen, Mengzhou; Wu, Shishan; Lin, Sicong; Shen, Jian

    2013-01-01

    A facile approach to modify silicone rubber (SR) membrane for improving the blood compatibility was investigated. The hydrophobic SR surface was firstly activated by air plasma, after which an initiator was immobilized on the activated surface for atom transfer radical polymerization (ATRP). Three zwitterionic polymers were then grafted from SR membrane via surface-initiated atom transfer radical polymerization (SI-ATRP). The surface composition, wettability, and morphology of the membranes before and after modification were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (WCA) measurement, and atomic force microscopy (AFM). Results showed that zwitterionic polymers were successfully grafted from SR surfaces, which remarkably improved the wettability of the SR surface. The blood compatibility of the membranes was evaluated by protein adsorption and platelet adhesion tests in vitro. As observed, all the zwitterionic polymer modified surfaces have improved resistance to nonspecific protein adsorption and have excellent resistance to platelet adhesion, showing significantly improved blood compatibility. This work should inspire many creative uses of SR based materials for biomedical applications such as vessel, catheter, and microfluidics. Highlights: • Facile surface modification of silicone rubber with functional brushes • Modified SR surfaces have improved resistance to nonspecific protein adsorption. • Modified SR surfaces have excellent resistance to platelet adhesion. • Zwitteironic surface significant improvement in blood compatibility • Could inspire many creative uses of SR based materials for biomedical

  14. Facile surface modification of silicone rubber with zwitterionic polymers for improving blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pingsheng [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Chen, Qiang, E-mail: chem100@nju.edu.cn [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); High Technology Research Institute of Nanjing University, Changzhou 213164 (China); Yuan, Bo; Chen, Mengzhou; Wu, Shishan; Lin, Sicong [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Shen, Jian, E-mail: shenj1957@yahoo.com.cn [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2013-10-15

    A facile approach to modify silicone rubber (SR) membrane for improving the blood compatibility was investigated. The hydrophobic SR surface was firstly activated by air plasma, after which an initiator was immobilized on the activated surface for atom transfer radical polymerization (ATRP). Three zwitterionic polymers were then grafted from SR membrane via surface-initiated atom transfer radical polymerization (SI-ATRP). The surface composition, wettability, and morphology of the membranes before and after modification were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (WCA) measurement, and atomic force microscopy (AFM). Results showed that zwitterionic polymers were successfully grafted from SR surfaces, which remarkably improved the wettability of the SR surface. The blood compatibility of the membranes was evaluated by protein adsorption and platelet adhesion tests in vitro. As observed, all the zwitterionic polymer modified surfaces have improved resistance to nonspecific protein adsorption and have excellent resistance to platelet adhesion, showing significantly improved blood compatibility. This work should inspire many creative uses of SR based materials for biomedical applications such as vessel, catheter, and microfluidics. Highlights: • Facile surface modification of silicone rubber with functional brushes • Modified SR surfaces have improved resistance to nonspecific protein adsorption. • Modified SR surfaces have excellent resistance to platelet adhesion. • Zwitteironic surface significant improvement in blood compatibility • Could inspire many creative uses of SR based materials for biomedical.

  15. Silane surface modification effects on the electromagnetic properties of phosphatized iron-based SMCs

    Science.gov (United States)

    Fan, Liang-Fang; Hsiang, Hsing-I.; Hung, Jia-Jing

    2018-03-01

    It is difficult to achieve homogeneous phosphatized iron powder dispersion in organic resins during the preparation of soft magnetic composites (SMCs). Inhomogeneous iron powder mixing in organic resins generally leads to the formation of micro-structural defects in SMCs and hence causes the magnetic properties to become worse. Phosphatized iron powder dispersion in organic resins can be improved by coating the phosphatized iron powder surfaces with a coupling agent. This study investigated the (3-aminopropyl) triethoxysilane (APTES) surface modification effects on the electromagnetic properties of phosphatized iron-based soft magnetic composites (SMCs). The results showed that the phosphatized iron powder surface can be modified using APTES to improve the phosphatized iron powder and epoxy resin compatibility and hence enhance phosphate iron powder epoxy mixing. The tensile strength, initial permeability, rated current under DC-bias superposition and magnetic loss in SMCs prepared using phosphatized iron powders can be effectively improved using APTES surface modification, which provides a promising candidate for power chip inductor applications.

  16. Laser surface modification of ultra-high-molecular-weight polyethylene (UHMWPE) for biomedical applications

    International Nuclear Information System (INIS)

    Riveiro, A.; Soto, R.; Val, J. del; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J.

    2014-01-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore, this material is being used in human orthopedic implants such as total hip or knee replacements. Surface modification of this material relates to changes on its chemistry, microstructure, roughness, and topography, all influencing its biological response. Surface treatment of UHMWPE is very difficult due to its high melt viscosity. This work presents a systematic approach to discern the role of different laser wavelengths (λ = 1064, 532, and 355 nm) on the surface modification of carbon coated UHMWPE samples. Influence of laser processing conditions (irradiance, pulse frequency, scanning speed, and spot overlapping) on the surface properties of this material was determined using an advanced statistical planning of experiments. A full factorial design of experiments was used to find the main effects of the processing parameters. The obtained results indicate the way to maximize surface properties which largely influence cell–material interaction.

  17. Laser surface modification of ultra-high-molecular-weight polyethylene (UHMWPE) for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Riveiro, A., E-mail: ariveiro@uvigo.es [Applied Physics Department, University of Vigo, ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Centro Universitario de la Defensa, Escuela Naval Militar, Plaza de España 2, 36920 Marín (Spain); Soto, R.; Val, J. del; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J. [Applied Physics Department, University of Vigo, ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

    2014-05-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) is a synthetic polymer used for biomedical applications because of its high impact resistance, ductility and stability in contact with physiological fluids. Therefore, this material is being used in human orthopedic implants such as total hip or knee replacements. Surface modification of this material relates to changes on its chemistry, microstructure, roughness, and topography, all influencing its biological response. Surface treatment of UHMWPE is very difficult due to its high melt viscosity. This work presents a systematic approach to discern the role of different laser wavelengths (λ = 1064, 532, and 355 nm) on the surface modification of carbon coated UHMWPE samples. Influence of laser processing conditions (irradiance, pulse frequency, scanning speed, and spot overlapping) on the surface properties of this material was determined using an advanced statistical planning of experiments. A full factorial design of experiments was used to find the main effects of the processing parameters. The obtained results indicate the way to maximize surface properties which largely influence cell–material interaction.

  18. Surface modification of ultra thin PES-zeolite using thermal annealing to increase flux and rejection of produced water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Widayat,; Pradini, A. W.; Armeli, Y. P. [Department of Chemical Engineering, University of Diponegoro Prof. Soedarto, Tembalang, Semarang, 50239, Phone/Fax : (024) 7460058 (Indonesia)

    2015-12-29

    Membrane technology is an alternative of water treatment based on filtration that is being developed. Surface Modification using heat treatment has been investigated to improve the performance of ultra thin PES-Zeolite nanocomposite membrane for produced water treatment from Pertamina Balongan. Two types of membranes with surface modification and without modification were prepared to study the effect of surface modification on its permeation properties. Asymmetric ultra thin PES-Zeolite nanocomposite membrane for produced water treatment was casted using the dry/wet phase inversion technique from dope solutions containing polyethersulfone, N-methyl-2-pyrrolidone (NMP) as a solvent and zeolite as a filler. Experimental results showed that the heat treatment at near glass transition temperature was increase the rejection of COD, Turbidity and ion Ca{sup 2+}. The better adherence of zeolite particles in the polymer matrix combined with formation of charge transfer complexes (CTCs) and cross-linking might be the main factors to enhance the percent of rejection. Field emission scanning electron microscopy (FESEM) micrographs showed that the selective layer and the substructure of PES-zeolite membrane became denser and more compact after the heat treatment. The FESEM micrographs also showed that the heat treatment was increased the adherence of zeolite particle and polymer. Membranes treated at 180 °C for 15 seconds indicated increase the rejection and small decrease in flux for produced water treatment.

  19. Surface modification technique of structural ceramics: ion implantation-assisted multi-arc ion plating

    International Nuclear Information System (INIS)

    Peng Zhijian; Miao Hezhuo; Si Wenjie; Qi Longhao; Li Wenzhi

    2003-01-01

    Through reviewing the advantages and disadvantages of the existed surface modification techniques, a new technique, ion implantation-assisted multi-arc ion plating, was proposed. Using the proposed technique, the surfaces of silicon nitride ceramics were modified by Ti ion implantation, and then three kinds of ternary coatings, (Ti,Al)N, (Ti,Zr)N and (Ti,Cr)N, were deposited on the as-implanted ceramics. The coatings prepared by this technique are of high-hardness and well adhesive to the ceramic substrates. The maximal hardness measured by nanoindentation tests is more than 40 GPa. The maximal critical load by nanoscratch tests is more than 60 mN. The cutting tools prepared by this technique with the presented coatings are of excellent performance in industrial applications. The technique may be promising for the surface modification of structural ceramics. (orig.)

  20. Surface Modification of SiO2 Microchannels with Biocompatible Polymer Using Supercritical Carbon Dioxide

    Science.gov (United States)

    Saito, Tatsuro; Momose, Takeshi; Hoshi, Toru; Takai, Madoka; Ishihara, Kazuhiko; Shimogaki, Yukihiro

    2010-11-01

    The surface of 500-mm-long microchannels in SiO2 microchips was modified using supercritical CO2 (scCO2) and a biocompatible polymer was coated on it to confer biocompatibility to the SiO2 surface. In this method, the SiO2 surface of a microchannel was coated with poly(ethylene glycol monomethacrylate) (PEGMA) as the biocompatible polymer using allyltriethoxysilane (ATES) as the anchor material in scCO2 as the reactive medium. Results were compared with those using the conventional wet method. The surface of a microchannel could not be modified by the wet method owing to the surface tension and viscosity of the liquid, but it was modified uniformly by the scCO2 method probably owing to the near-zero surface tension, low viscosity, and high diffusivity of scCO2. The effect of the surface modification by the scCO2 method to prevent the adsorption of protein was as high as that of the modification by the wet method. Modified microchips can be used in biochemical and medical analyses.

  1. Near-surface modifications for improved crack tolerant behavior of high strength alloys: trends and prospects

    International Nuclear Information System (INIS)

    Hettche, L.R.; Rath, B.B.

    1982-01-01

    The purpose of this chapter is to examine the potential of surface modifications in improving the crack tolerant behavior of high strength alloys. Provides a critique of two of the most promising and versatile techniques: ion implantation and laser beam surface processing. Discusses crack tolerant properties; engineering characterization; publication trends and Department of Defense interests; and emergent surface modification techniques. Finds that the efficiency with which high strength alloys can be incorporated into a structure or component is dependent on the following crack tolerant properties: fracture toughness, fatigue resistance, sustained loading cracking resistance, fretting fatigue resistance, and hydrogen embrittlement resistance. Concludes that ion implantation and laser surface processing coupled with other advanced metallurgical procedures and fracture mechanic analyses provide the means to optimize both the bulk and surface controlled crack tolerant properties

  2. Modification of the surface of superparamagnetic iron oxide nanoparticles to enable their safe application in humans.

    Science.gov (United States)

    Strehl, Cindy; Maurizi, Lionel; Gaber, Timo; Hoff, Paula; Broschard, Thomas; Poole, A Robin; Hofmann, Heinrich; Buttgereit, Frank

    Combined individually tailored methods for diagnosis and therapy (theragnostics) could be beneficial in destructive diseases, such as rheumatoid arthritis. Nanoparticles are promising candidates for theragnostics due to their excellent biocompatibility. Nanoparticle modifications, such as improved surface coating, are in development to meet various requirements, although safety concerns mean that modified nanoparticles require further review before their use in medical applications is permitted. We have previously demonstrated that iron oxide nanoparticles with amino-polyvinyl alcohol (a-PVA) adsorbed on their surfaces have the unwanted effect of increasing human immune cell cytokine secretion. We hypothesized that this immune response was caused by free-floating PVA. The aim of the present study was to prevent unwanted immune reactions by further surface modification of the a-PVA nanoparticles. After cross-linking of PVA to nanoparticles to produce PVA-grafted nanoparticles, and reduction of their zeta potential, the effects on cell viability and cytokine secretion were analyzed. PVA-grafted nanoparticles still stimulated elevated cytokine secretion from human immune cells; however, this was inhibited after reduction of the zeta potential. In conclusion, covalent cross-linking of PVA to nanoparticles and adjustment of the surface charge rendered them nontoxic to immune cells, nonimmunogenic, and potentially suitable for use as theragnostic agents.

  3. Surface Modification of Photoresist SU-8 for Low Autofluorescence and Bioanalytical Applications

    DEFF Research Database (Denmark)

    Cao, Cuong; Birtwell, Sam W.; Høgberg, Jonas

    2011-01-01

    This paper reports a surface modification of epoxy-based negative photoresist SU-8 for reducing its autofluorescence while enhancing its biofunctionality. By covalently depositing a thin layer of 20 nm Au nanoparticles (AuNPs) onto the SU-8 surface, we found that the AuNPs-coated SU-8 surface...... is much less fluorescent than the untreated SU-8. Moreover, DNA probes can easily be immobilized on the Au surface and are thermally stable over a wide range of temperature. These improvements will benefit bioanalytical applications such as DNA hybridization and solid-phase PCR (SP-PCR)....

  4. Innovative coatings and surface modification of titanium for sea water condenser applications

    International Nuclear Information System (INIS)

    George, R.P.; Anandkumar, B.; Vanithakumari, S.C.; Kamachi Mudali, U.

    2016-01-01

    titanium surfaces. Superhydrophobic surface modification is attempted on titanium by preparing micro-nano textured surfaces through mechanical and chemical methods, and applying low surface energy coatings, for antibacterial activity and biofouling resistance. A silver nanoparticle loaded TiO 2 nanoporous layer for visible light induced antimicrobial applications was also developed. This paper describes the various successes achieved in this direction. (author)

  5. Application of MEVVA discharge to material surface modification

    International Nuclear Information System (INIS)

    Gao Yu; Geng Man; Huang Yuming; Gong Xiaorong; Yu Yijun; Tang Deli; Tie Jun

    1996-01-01

    The authors describes some characteristics of the MEVVA discharge, the process of generating a cathode-arc plasma and the advantages of the MEVVA discharge compared with the kind of heating-vaporizing-ionizing source. Some practical parameters and the operating process of the MEVVA ion source as well as a plasma source with MEVVA discharge used in a PSII device are presented. Various plasmas having good-quality and high-performance are obtained with MEVVA discharges and have been widely used in sight-line processing and omnibearing ion implantation for material surface modification

  6. In vitro modifications of the scala tympani environment and the cochlear implant array surface.

    Science.gov (United States)

    Kontorinis, Georgios; Scheper, Verena; Wissel, Kirsten; Stöver, Timo; Lenarz, Thomas; Paasche, Gerrit

    2012-09-01

    To investigate the influence of alterations of the scala tympani environment and modifications of the surface of cochlear implant electrode arrays on insertion forces in vitro. Research experimental study. Fibroblasts producing neurotrophic factors were cultivated on the surface of Nucleus 24 Contour Advance electrodes. Forces were recorded by an Instron 5542 Force Measurement System as three modified arrays were inserted into an artificial scala tympani model filled with phosphate-buffered saline (PBS). The recorded forces were compared to control groups including three unmodified electrodes inserted into a model filled with PBS (unmodified environment) or Healon (current practice). Fluorescence microscopy was used before and after the insertions to identify any remaining fibroblasts. Additionally, three Contour Advance electrodes were inserted into an artificial model, filled with alginate/barium chloride solution at different concentrations, while insertion forces were recorded. Modification of the scala tympani environment with 50% to 75% alginate gel resulted in a significant decrease in the insertion forces. The fibroblast-coated arrays also led to decreased forces comparable to those recorded with Healon. Fluorescence microscopy revealed fully cell-covered arrays before and partially covered arrays after the insertion; the fibroblasts on the arrays' modiolar surface remained intact. Modifications of the scala tympani's environment with 50% to 75% alginate/barium chloride and of the cochlear implant electrode surface with neurotrophic factor-producing fibroblasts drastically reduce the insertion forces. As both modifications may serve future intracochlear therapies, it is expected that these might additionally reduce possible insertion trauma. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  7. Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

    Science.gov (United States)

    Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

    2016-12-01

    Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

  8. Surface modification of plasmonic nanostructured materials with thiolated oligonucleotides in 10 seconds using selective microwave heating

    International Nuclear Information System (INIS)

    Abel, B.; Aslan, K.

    2012-01-01

    This study demonstrates the proof-of-principle of rapid surface modification of plasmonic nanostructured materials with oligonucleotides using low power microwave heating. Due to their interesting optical and electronic properties, silver nanoparticle films (SNFs, 2 nm thick) deposited onto glass slides were used as the model plasmonic nanostructured materials. Rapid surface modification of SNFs with oligonucleotides was carried out using two strategies (1) Strategy 1: for ss-oligonucleotides, surface hybridization and (2) Strategy 2: for ds-oligonucleotides, solution hybridization, where the samples were exposed to 10, 15, 30 and 60 seconds microwave heating. To assess the efficacy of our new rapid surface modification technique, identical experiments carried out without the microwave heating (i.e., conventional method), which requires 24 hours for the completion of the identical steps. It was found that SNFs can be modified with ss- and ds-oligonucleotides in 10 seconds, which typically requires several hours of incubation time for the chemisorption of thiol groups on to the planar metal surface using conventional techniques. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

    Science.gov (United States)

    Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

    2016-07-01

    Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Spatial and temporal control of the diazonium modification of sp2 carbon surfaces.

    Science.gov (United States)

    Kirkman, Paul M; Güell, Aleix G; Cuharuc, Anatolii S; Unwin, Patrick R

    2014-01-08

    Interest in the controlled chemical functionalization of sp(2) carbon materials using diazonium compounds has been recently reignited, particularly as a means to generate a band gap in graphene. We demonstrate local diazonium modification of pristine sp(2) carbon surfaces, with high control, at the micrometer scale through the use of scanning electrochemical cell microscopy (SECCM). Electrochemically driven diazonium patterning is investigated at a range of driving forces, coupled with surface analysis using atomic force microscopy (AFM) and Raman spectroscopy. We highlight how the film density, level of sp(2)/sp(3) rehybridization and the extent of multilayer formation can be controlled, paving the way for the use of localized electrochemistry as a route to controlled diazonium modification.

  11. Chemical modification of glass surface with a monolayer of nonchromophoric and chromophoric methacrylate terpolymer

    Energy Technology Data Exchange (ETDEWEB)

    Janik, Ryszard [Department of Polymer Engineering and Technology, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Kucharski, Stanislaw, E-mail: stanislaw.kucharski@pwr.wroc.pl [Department of Polymer Engineering and Technology, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Sobolewska, Anna [Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Barille, Regis [Institut des Sciences et Techniques Moleculaires d' Angers ' Moltech Anjou' , CNRS UMR 6200, 49045 Angers (France)

    2010-11-15

    The methacrylate terpolymers, a nonchromophoric and chromophoric one, containing 2-hydroxyethyl groups were reacted with 3-isocyanatopropyltriethoxysilane to obtain reactive polymers able to form covalent bonding with -SiOH groups of the glass surface via triethoxysilane group condensation. Chemical modification of the Corning 2949 glass plates treated in this way resulted in increase of wetting angle from 11{sup o} to ca. 70-73{sup o}. Determination of ellipsometric parameters revealed low value of the substrate refractive index as compared with that of bulk Corning 2949 glass suggesting roughness of the surface. The AFM image of the bare glass surface and that modified with terpolymer monolayer confirmed this phenomenon. Modification of the glass with the terpolymer monolayer made it possible to create the substrate surface well suited for deposition of familiar chromophore film by spin-coating. The chromophore polymer film deposited onto the modified glass surface was found to be resistant to come unstuck in aqueous solution.

  12. Directly thiolated modification onto the surface of detonation nanodiamonds.

    Science.gov (United States)

    Hsu, Ming-Hua; Chuang, Hong; Cheng, Fong-Yu; Huang, Ying-Pei; Han, Chien-Chung; Chen, Jiun-Yu; Huang, Su-Chin; Chen, Jen-Kun; Wu, Dian-Syue; Chu, Hsueh-Liang; Chang, Chia-Ching

    2014-05-28

    An efficient method for modifying the surface of detonation nanodiamonds (5 and 100 nm) with thiol groups (-SH) by using an organic chemistry strategy is presented herein. Thiolated nanodiamonds were characterized by spectroscopic techniques, and the atomic percentage of sulfur was analyzed by elemental analysis and X-ray photoelectron spectroscopy. The conjugation between thiolated nanodiamonds and gold nanoparticles was elucidated by transmission electron microscopy and UV-vis spectrometry. Moreover, the material did not show significant cytotoxicity to the human lung carcinoma cell line and may prospectively be applied in bioconjugated technology. The new method that we elucidated may significantly improve the approach to surface modification of detonation nanodiamonds and build up a new platform for the application of nanodiamonds.

  13. Surface modification of seawater desalination reverse osmosis membranes: Characterization studies & performance evaluation

    KAUST Repository

    Matin, Asif

    2014-06-01

    In this work we report surface modification of commercial reverse osmosis membranes by depositing ultrathin copolymer coatings, which could potentially enhance the biofouling resistance of RO membranes. Hydrophilic monomer hydroxyethyl methacrylate (HEMA) and a hydrophobic monomer, perfluorodecyl acrylate (PFDA) were copolymerized directly on the active layer of commercial aromatic polyamide reverse osmosis (RO) membranes using an initiated Chemical Vapor Deposition (iCVD) technique. Attenuated total reflective Fourier transform infrared spectra (ATR-FTIR) verified the successful modification of the membrane surfaces as a new FTIR adsorption band around 1730cm-1 corresponding to carbonyl groups in the copolymer film appeared after the deposition. X-ray Photoelectron spectroscopy (XPS) analysis also confirmed the presence of the copolymer film on the membrane surface by showing strong fluorine peaks emanating from the fluorinated alkyl side chains of the PFA molecules. Contact angle measurements with deionized water showed the modified membrane surfaces to be initially very hydrophobic but quickly assumed a hydrophilic character within few minutes. Atomic Force Microscopy (AFM) revealed that the deposited films were smooth and conformal as the surface topology of the underlying membrane surface remained virtually unchanged after the deposition. FESEM images of the top surface also showed that the typical ridge-and-valley structure associated with polyamide remained intact after the deposition. Short-term permeation tests using DI water and 2000ppm NaCl water showed that the deposited copolymer coatings had negligible effect on permeate water flux and salt rejection. © 2013 Elsevier B.V.

  14. Surface modification and characterization of magnesium hydroxide sulfate hydrate nanowhiskers

    Energy Technology Data Exchange (ETDEWEB)

    Gao Chuanhui [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Li Xianguo, E-mail: chuanhuigao@foxmail.com [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Feng Lijuan; Lu Shaoyan; Liu Jinyan [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China)

    2010-03-01

    In order to enhance the compatibility with plastic polymers, magnesium hydroxide sulfate hydrate (MHSH) nanowhiskers were modified through grafting methyl methacrylate (MMA) on the surface of the nanowhiskers by emulsion polymerization. The influences of the reaction time, MMA monomer content, adding speed of monomer and the reaction temperature on the grafting ratio were investigated. Thermogravimetry (TG), Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy and surface contact angle measurement were used to characterize the effect of surface modification. The results showed that the MHSH nanowhiskers were uniformly coated by polymethyl methacrylate (PMMA), and a well-defined core-shell hybrid structure of MHSH/PMMA was obtained. The surface contact angle of the hybrid whiskers increased to 87.32 deg. from 12.71 deg. and the whiskers surface was changed from hydrophilic to lipophilic.

  15. Surface-segregated monolayers: a new type of ordered monolayer for surface modification of organic semiconductors.

    Science.gov (United States)

    Wei, Qingshuo; Tajima, Keisuke; Tong, Yujin; Ye, Shen; Hashimoto, Kazuhito

    2009-12-09

    We report a new type of ordered monolayer for the surface modification of organic semiconductors. Fullerene derivatives with fluorocarbon chains ([6,6]-phenyl-C(61)-buryric acid 1H,1H-perfluoro-1-alkyl ester or FC(n)) spontaneously segregated as a monolayer on the surface of a [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) film during a spin-coating process from the mixture solutions, as confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet photoelectron spectroscopy (UPS) showed the shift of ionization potentials (IPs) depending on the fluorocarbon chain length, indicating the formation of surface dipole moments. Surface-sensitive vibrational spectroscopy, sum frequency generation (SFG) revealed the ordered molecular orientations of the C(60) moiety in the surface FC(n) layers. The intensity of the SFG signals from FC(n) on the surface showed a clear odd-even effect when the length of the fluorocarbon chain was changed. This new concept of the surface-segregated monolayer provides a facile and versatile approach to modifying the surface of organic semiconductors and is applicable to various organic optoelectronic devices.

  16. Tailoring the Wettability of Colloidal Particles for Pickering Emulsions via Surface Modification and Roughness

    Directory of Open Access Journals (Sweden)

    Meina Xiao

    2018-06-01

    Full Text Available Pickering emulsions are water or oil droplets that are stabilized by colloidal particles and have been intensely studied since the late 90s. The surfactant-free nature of these emulsions has little adverse effects such as irritancy and contamination of environment and typically exhibit enhanced stability compared to surfactant-stabilized emulsions. Therefore, they offer promising applications in cosmetics, food science, controlled release, and the manufacturing of microcapsules and porous materials. The wettability of the colloidal particles is the main parameter determining the formation and stability of Pickering emulsions. Tailoring the wettability by surface chemistry or surface roughness offers considerable scope for the design of a variety of hybrid nanoparticles that may serve as novel efficient Pickering emulsion stabilizers. In this review, we will discuss the recent advances in the development of surface modification of nanoparticles.

  17. Altering protein surface charge with chemical modification modulates protein–gold nanoparticle aggregation

    International Nuclear Information System (INIS)

    Jamison, Jennifer A.; Bryant, Erika L.; Kadali, Shyam B.; Wong, Michael S.; Colvin, Vicki L.; Matthews, Kathleen S.; Calabretta, Michelle K.

    2011-01-01

    Gold nanoparticles (AuNP) can interact with a wide range of molecules including proteins. Whereas significant attention has focused on modifying the nanoparticle surface to regulate protein–AuNP assembly or influence the formation of the protein “corona,” modification of the protein surface as a mechanism to modulate protein–AuNP interaction has been less explored. Here, we examine this possibility utilizing three small globular proteins—lysozyme with high isoelectric point (pI) and established interactions with AuNP; α-lactalbumin with similar tertiary fold to lysozyme but low pI; and myoglobin with a different globular fold and an intermediate pI. We first chemically modified these proteins to alter their charged surface functionalities, and thereby shift protein pI, and then applied multiple methods to assess protein–AuNP assembly. At pH values lower than the anticipated pI of the modified protein, AuNP exposure elicits changes in the optical absorbance of the protein–NP solutions and other properties due to aggregate formation. Above the expected pI, however, protein–AuNP interaction is minimal, and both components remain isolated, presumably because both species are negatively charged. These data demonstrate that protein modification provides a powerful tool for modulating whether nanoparticle–protein interactions result in material aggregation. The results also underscore that naturally occurring protein modifications found in vivo may be critical in defining nanoparticle–protein corona compositions.

  18. Plasma processing of large curved surfaces for superconducting rf cavity modification

    Directory of Open Access Journals (Sweden)

    J. Upadhyay

    2014-12-01

    Full Text Available Plasma-based surface modification of niobium is a promising alternative to wet etching of superconducting radio frequency (SRF cavities. We have demonstrated surface layer removal in an asymmetric nonplanar geometry, using a simple cylindrical cavity. The etching rate is highly correlated with the shape of the inner electrode, radio-frequency (rf circuit elements, gas pressure, rf power, chlorine concentration in the Cl_{2}/Ar gas mixtures, residence time of reactive species, and temperature of the cavity. Using variable radius cylindrical electrodes, large-surface ring-shaped samples, and dc bias in the external circuit, we have measured substantial average etching rates and outlined the possibility of optimizing plasma properties with respect to maximum surface processing effect.

  19. MEMS-based dynamic cell-to-cell culture platforms using electrochemical surface modifications

    International Nuclear Information System (INIS)

    Chang, Jiyoung; Lin, Liwei; Yoon, Sang-Hee; Mofrad, Mohammad R K

    2011-01-01

    MEMS-based biological platforms with the capability of both spatial placements and time releases of living cells for cell-to-cell culture experiments have been designed and demonstrated utilizing electrochemical surface modification effects. The spatial placement is accomplished by electrochemical surface modification of substrate surfaces to be either adhesive or non-adhesive for living cells. The time control is achieved by the electrical activation of the selective indium tin oxide co-culture electrode to allow the migration of living cells onto the electrode to start the cell-to-cell culture studies. Prototype devices have a three-electrode design with an electrode size of 50 × 50 µm 2 and the separation gaps of 2 µm between them. An electrical voltage of −1.5 V has been used to activate the electrodes independently and sequentially to demonstrate the dynamic cell-to-cell culture experiments of NIH 3T3 fibroblast and Madin Darby canine kidney cells. As such, this MEMS platform could be a basic yet versatile tool to characterize transient cell-to-cell interactions

  20. Interaction of progenitor bone cells with different surface modifications of titanium implant

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chen, Ya-Shun [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Lin, Yi; Kuo, Tzu-Huang; Kuo, Hsien-Nan [Medical Device Development Division, Metal Industries Research and Development Centre, Kaohsiung 82151, Taiwan (China)

    2014-04-01

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  1. Interaction of progenitor bone cells with different surface modifications of titanium implant

    International Nuclear Information System (INIS)

    Chen, Wen-Cheng; Chen, Ya-Shun; Ko, Chia-Ling; Lin, Yi; Kuo, Tzu-Huang; Kuo, Hsien-Nan

    2014-01-01

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  2. Drag reduction in reservoir rock surface: Hydrophobic modification by SiO{sub 2} nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yong-Li, E-mail: yylhill@163.com [College of Chemistry & Chemical Engineering, Xi’an Shiyou University, Xi’an 710065 (China); Cui, Ming-Yue; Jiang, Wei-Dong; He, An-Le; Liang, Chong [Langfang Branch of Research Institute of Petroleum Exploration & Development, Langfang 065007 (China)

    2017-02-28

    Graphical abstract: The micro-nanoscale hierarchical structures at the sandstone core surface are constructed by adsorption of the modified silica nanoparticles, which leads to the effect of drag reduction to improve the low injection rate in ultra-low permeability reservoirs. - Highlights: • A micro-nanoscale hierarchical structure is formed at the reservoir rock surface. • An inversion has happened from hydrophilic into hydrophobic modified by nanofluids. • The effect of drag reduction to improve the low injection rate is realized. • The mechanism of drag reduction induced from the modified core surface was unclosed. - Abstract: Based on the adsorption behavior of modified silica nanoparticles in the sandstone core surface, the hydrophobic surface was constructed, which consists of micro-nanoscale hierarchical structure. This modified core surface presents a property of drag reduction and meets the challenge of high injection pressure and low injection rate in low or ultra-low permeability reservoir. The modification effects on the surface of silica nanoparticles and reservoir cores, mainly concerning hydrophobicity and fine structure, were determined by measurements of contact angle and scanning electron microscopy. Experimental results indicate that after successful modification, the contact angle of silica nanoparticles varies from 19.5° to 141.7°, exhibiting remarkable hydrophobic properties. These modified hydrophobic silica nanoparticles display a good adsorption behavior at the core surface to form micro-nanobinary structure. As for the wettability of these modified core surfaces, a reversal has happened from hydrophilic into hydrophobic and its contact angle increases from 59.1° to 105.9°. The core displacement experiments show that the relative permeability for water has significantly increased by an average of 40.3% via core surface modification, with the effects of reducing injection pressure and improving injection performance of water

  3. Surface-defect induced modifications in the optical properties of α-MnO{sub 2} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    John, Reenu Elizabeth [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India); Chandran, Anoop [School of Pure and Applied Physics, MG University, Kottayam, Kerala 686560 (India); Thomas, Marykutty [Department of Physics, BCM College, Kottayam, Kerala 686001 (India); Jose, Joshy [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India); George, K.C., E-mail: drkcgeorge@gmail.com [Department of Physics, St. Berchmans College, Changanassery, Kerala 686101 (India)

    2016-03-30

    Graphical abstract: - Highlights: • Alpha-MnO{sub 2} nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO{sub 2} nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO{sub 6} octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn{sup 3+}) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO{sub 2}. These

  4. Simple surface modification of poly(dimethylsiloxane) for DNA hybridization

    Science.gov (United States)

    Zhou, Jinwen; Voelcker, Nicolas H.; Ellis, Amanda V.

    2010-01-01

    Here, we present a simple chemical modification of poly(dimethylsiloxane) (PDMS) by curing a mixture of 2 wt% undecylenic acid (UDA) in PDMS prepolymer on a gold-coated glass slide. This gold slide had been previously pretreated with a self-assembled hydrophilic monolayer of 3-mercaptopropionic acid (MPA). During curing of the UDA∕PDMS prepolymer, the hydrophilic UDA carboxyl moieties diffuses toward the hydrophilic MPA carboxyl moieties on the gold surface. This diffusion of the UDA within the PDMS prepolymer to the surface is a direct result of surface energy minimization. Once completely cured, the PDMS is peeled off the gold substrate, thereby exposing the interfacial carboxyl groups. These groups are then available for subsequent attachment of 5′-amino terminated DNA oligonucleotides via amide linkages. Our results show that the covalently tethered oligonucleotides can successfully capture fluorescein-labeled complementary oligonucleotides via hybridization, which are visualized using fluorescence microscopy. PMID:21264061

  5. Electrochemical surface modification of titanium in dentistry.

    Science.gov (United States)

    Kim, Kyo-Han; Ramaswamy, Narayanan

    2009-01-01

    Titanium and its alloys have good biocompatibility with body cells and tissues and are widely used for implant applications. However, clinical procedures place more stringent and tough requirements on the titanium surface necessitating artificial surface treatments. Among the many methods of titanium surface modification, electrochemical techniques are simple and cheap. Anodic oxidation is the anodic electrochemical technique while electrophoretic and cathodic depositions are the cathodic electrochemical techniques. By anodic oxidation it is possible to obtain desired roughness, porosity and chemical composition of the oxide. Anodic oxidation at high voltages can improve the crystallinity of the oxide. The chief advantage of this technique is doping of the coating of the bath constituents and incorporation of these elements improves the properties of the oxide. Electrophoretic deposition uses hydroxyapatite (HA) powders dispersed in a suitable solvent at a particular pH. Under these operating conditions these particles acquire positive charge and coatings are obtained on the cathodic titanium by applying an external electric field. These coatings require a post-sintering treatment to improve the coating properties. Cathodic deposition is another type of electrochemical method where HA is formed in situ from an electrolyte containing calcium and phosphate ions. It is also possible to alter structure and/or chemistry of the obtained deposit. Nano-grained HA has higher surface energy and greater biological activity and therefore emphasis is being laid to produce these coatings by cathodic deposition.

  6. Surface modification of biomaterials by pulsed laser ablation deposition and plasma/gamma polymerization

    Science.gov (United States)

    Rau, Kaustubh R.

    Surface modification of stainless-steel was carried out by two different methods: pulsed laser ablation deposition (PLAD) and a combined plasma/gamma process. A potential application was the surface modification of endovascular stents, to enhance biocompatibility. The pulsed laser ablation deposition process, had not been previously reported for modifying stents and represented a unique and potentially important method for surface modification of biomaterials. Polydimethylsiloxane (PDMS) elatomer was studied using the PLAD technique. Cross- linked PDMS was deemed important because of its general use for biomedical implants and devices as well as in other fields. Furthermore, PDMS deposition using PLAD had not been previously studied and any information gained on its ablation characteristics could be important scientifically and technologically. The studies reported here showed that the deposited silicone film properties had a dependence on the laser energy density incident on the target. Smooth, hydrophobic, silicone-like films were deposited at low energy densities (100-150 mJ/cm2). At high energy densities (>200 mJ/cm2), the films had an higher oxygen content than PDMS, were hydrophilic and tended to show a more particulate morphology. It was also determined that (1)the deposited films were stable and extremely adherent to the substrate, (2)silicone deposition exhibited an `incubation effect' which led to the film properties changing with laser pulse number and (3)films deposited under high vacuum were similar to films deposited at low vacuum levels. The mechanical properties of the PLAD films were determined by nanomechanical measurements which are based on the Atomic Force Microscope (AFM). From these measurements, it was possible to determine the modulus of the films and also study their scratch resistance. Such measurement techniques represent a significant advance over current state-of-the-art thin film characterization methods. An empirical model for

  7. RF plasma based selective modification of hydrophilic regions on super hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaehyun; Hwang, Sangyeon; Cho, Dae-Hyun [Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Hong, Jungwoo [Department of Mechanical Engineering, Graduate of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Shin, Jennifer H., E-mail: j_shin@kaist.ac.kr [Department of Mechanical Engineering, Graduate of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Byun, Doyoung, E-mail: dybyun@skku.edu [Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of)

    2017-02-01

    Highlights: • Simple and amenable reforming method for a substrate with disparate patterns of hydrophilic dots on super-hydrophobic surfaces is proposed. • Wettability characteristics and modification mechanism for the surfaces are conducted and revealed through SEM, AFM, WSI, and SIMS. • Several representative materials for various applications are successfully deposited. - Abstract: Selective modification and regional alterations of the surface property have gained a great deal of attention to many engineers. In this paper, we present a simple, a cost-effective, and amendable reforming method for disparate patterns of hydrophilic regions on super-hydrophobic surfaces. Uniform super-hydrophobic layer (Contact angle; CA > 150°, root mean square (RMS) roughness ∼0.28 nm) can be formed using the atmospheric radio frequency (RF) plasma on top of the selective hydrophilic (CA ∼ 70°, RMS roughness ∼0.34 nm) patterns imprinted by electrohydrodynamic (EHD) jet printing technology with polar alcohols (butyl carbitol or ethanol). The wettability of the modified surface was investigated qualitatively utilizing scanning electron microscopy (SEM), atomic force microscopy (AFM), and wavelength scanning interferometer (WSI). Secondary ion mass spectroscopy (SIMS) analysis showed that the alcohol addiction reaction changed the types of radicals on the super-hydrophobic surface. The wettability was found to depend sensitively on chemical radicals on the surface, not on surface morphology (particle size and surface roughness). Furthermore, three different kinds of representative hydrophilic samples (polystyrene nano-particle aqueous solution, Salmonella bacteria medium, and poly(3,4-ethylenediocythiophene) ink) were tested for uniform deposition onto the desired hydrophilic regions. This simple strategy would have broad applications in various research fields that require selective deposition of target materials.

  8. RF plasma based selective modification of hydrophilic regions on super hydrophobic surface

    International Nuclear Information System (INIS)

    Lee, Jaehyun; Hwang, Sangyeon; Cho, Dae-Hyun; Hong, Jungwoo; Shin, Jennifer H.; Byun, Doyoung

    2017-01-01

    Highlights: • Simple and amenable reforming method for a substrate with disparate patterns of hydrophilic dots on super-hydrophobic surfaces is proposed. • Wettability characteristics and modification mechanism for the surfaces are conducted and revealed through SEM, AFM, WSI, and SIMS. • Several representative materials for various applications are successfully deposited. - Abstract: Selective modification and regional alterations of the surface property have gained a great deal of attention to many engineers. In this paper, we present a simple, a cost-effective, and amendable reforming method for disparate patterns of hydrophilic regions on super-hydrophobic surfaces. Uniform super-hydrophobic layer (Contact angle; CA > 150°, root mean square (RMS) roughness ∼0.28 nm) can be formed using the atmospheric radio frequency (RF) plasma on top of the selective hydrophilic (CA ∼ 70°, RMS roughness ∼0.34 nm) patterns imprinted by electrohydrodynamic (EHD) jet printing technology with polar alcohols (butyl carbitol or ethanol). The wettability of the modified surface was investigated qualitatively utilizing scanning electron microscopy (SEM), atomic force microscopy (AFM), and wavelength scanning interferometer (WSI). Secondary ion mass spectroscopy (SIMS) analysis showed that the alcohol addiction reaction changed the types of radicals on the super-hydrophobic surface. The wettability was found to depend sensitively on chemical radicals on the surface, not on surface morphology (particle size and surface roughness). Furthermore, three different kinds of representative hydrophilic samples (polystyrene nano-particle aqueous solution, Salmonella bacteria medium, and poly(3,4-ethylenediocythiophene) ink) were tested for uniform deposition onto the desired hydrophilic regions. This simple strategy would have broad applications in various research fields that require selective deposition of target materials.

  9. Amino-functionalized surface modification of polyacrylonitrile hollow fiber-supported polydimethylsiloxane membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Leiqing; Cheng, Jun, E-mail: juncheng@zju.edu.cn; Li, Yannan; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2017-08-15

    Highlights: • Amino group was introduced to improve surface polarity of PDMS membrane. • The water contact angle of PDMS membrane decreased after the modification. • The concentration of N atom on surface of PDMS membrane reached up to ∼6%. • The density of PDMS membrane decreased while the swelling degree increased. • CO{sub 2} permeability increased while selectivity decreased after the modification. - Abstract: This study aimed to improve surface polarity of polydimethylsiloxane (PDMS) membranes and provide surface active sites which were easy to react with other chemicals. 3-Aminopropyltriethoxysilane (APTES) containing an amino group was introduced into a PDMS membrane by crosslinking to prepare polyacrylonitrile hollow fiber-supported PDMS membranes with an amino-functionalized surface. Fourier transform infrared and X-ray photoelectron spectroscopic analyses proved the existence of APTES and its amino group in the PDMS membrane. The concentration of N atoms on the PDMS membrane surface reached ∼6% when the mass ratio of APTES/PDMS oligomer in the PDMS coating solution was increased to 4/3. The water contact angle decreased from ∼114° to ∼87.5°, indicating the improved surface polarization of the PDMS membrane. The density and swelling degree of the PDMS membrane decreased and increased, respectively, with increasing APTES content in PDMS. This phenomenon increased CO{sub 2} permeability and decreased CO{sub 2}/H{sub 2} selectivity, CO{sub 2}/CH{sub 4} selectivity, and CO{sub 2}/N{sub 2} selectivity. When the mass ratio of APTES/PDMS oligomer was increased from 0 to 4/3, the CO{sub 2} permeation rate of the hollow fiber-supported PDMS membranes initially decreased from ∼2370 GPU to ∼860 GPU and then increased to ∼2000 GPU due to the change in coating solution viscosity.

  10. Surface modification of Ti dental implants by Nd:YVO4 laser irradiation

    International Nuclear Information System (INIS)

    Braga, Francisco J.C.; Marques, Rodrigo F.C.; Filho, Edson de A.; Guastaldi, Antonio C.

    2007-01-01

    Surface modifications have been applied in endosteal bone devices in order to improve the osseointegration through direct contact between neoformed bone and the implant without an intervening soft tissue layer. Surface characteristics of titanium implants have been modified by addictive methods, such as metallic titanium, titanium oxide and hydroxyapatite powder plasma spray, as well as by subtractive methods, such as acid etching, acid etching associated with sandblasting by either AlO 2 or TiO 2 , and recently by laser ablation. Surface modification for dental and medical implants can be obtained by using laser irradiation technique where its parameters like repetition rate, pulse energy, scanning speed and fluency must be taken into accounting to the appropriate surface topography. Surfaces of commercially pure Ti (cpTi) were modified by laser Nd:YVO 4 in nine different parameters configurations, all under normal atmosphere. The samples were characterized by SEM and XRD refined by Rietveld method. The crystalline phases αTi, βTi, Ti 6 O, Ti 3 O and TiO were formed by the melting and fast cooling processes during irradiation. The resulting phases on the irradiated surface were correlated with the laser beam parameters. The aim of the present work was to control titanium oxides formations in order to improve implants osseointegration by using a laser irradiation technique which is of great importance to biomaterial devices due to being a clean and reproducible process

  11. Influence of tungsten microstructure and ion flux on deuterium plasma-induced surface modifications and deuterium retention

    Energy Technology Data Exchange (ETDEWEB)

    Buzi, Luxherta [IEK - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Juelich (Germany); FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research (Netherlands); Ghent University (Belgium); Temmerman, Greg de [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research (Netherlands); Reinhart, Michael; Matveev, Dmitry; Unterberg, Bernhard; Wienhold, Peter; Breuer, Uwe; Kreter, Arkadi [IEK - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Juelich (Germany); Oost, Guido van [Ghent University (Belgium)

    2014-07-01

    Tungsten is to be used as plasma-facing material for the ITER divertor due to its favourable thermal properties, low erosion and fuel retention. Bombardment of tungsten by low energy ions of hydrogen isotopes, at different surface temperature, can lead to surface modifications and influence the fuel accumulation in the material. This contribution will assess the impact of material microstructure and the correlation between the particle flux, surface modifications and deuterium retention in tungsten. Tungsten samples were exposed to deuterium plasma at a surface temperature of 510 K, 670 K and 870 K, ion energy of 40 eV and ion fluence of 10{sup 26} m{sup -2}. The high and low ion flux ranges were in the order 10{sup 24} m{sup -2}s{sup -1} and 10{sup 22} m{sup -2}s{sup -1}. Depth profiling of deuterium in all the samples was done by secondary ion mass spectroscopy technique and a scanning electron microscope was used to investigate the surface modifications. Modelling of the D desorption spectra with the coupled reaction diffusion system model will be also presented.

  12. Laser- and UV-assisted modification of polystyrene surfaces for control of protein adsorption and cell adhesion

    International Nuclear Information System (INIS)

    Pfleging, Wilhelm; Torge, Maika; Bruns, Michael; Trouillet, Vanessa; Welle, Alexander; Wilson, Sandra

    2009-01-01

    An appropriate choice of laser and process parameters enables new approaches for the fabrication of polymeric lab-on-chip devices with integrated functionalities. We will present our current research results in laser-assisted modification of polystyrene (PS) with respect to the fabrication of polymer devices for cell culture applications. For this purpose laser micro-patterning of PS and subsequent surface functionalization was investigated as function of laser and process parameters. A high power ArF-excimer laser radiation source with a pulse length of 19 ns as well as a high repetition ArF-excimer laser source with a pulse length of 5 ns were used in order to study the influence of laser pulse length on laser-induced surface oxidation. The change in surface chemistry was characterized by X-ray photoelectron spectroscopy and contact angle measurements. The difference between laser-assisted modification versus UV-lamp assisted modification was investigated. A photolytic activation of specific areas of the polymer surface and subsequent oxidization in oxygen or ambient air leads to a chemically modified polymer surface bearing carboxylic acid groups well-suited for controlled competitive protein adsorption or protein immobilization. Finally, distinct areas for cell growth and adhesion are obtained

  13. Surface modification of polylactic acid films by atmospheric pressure plasma treatment

    Science.gov (United States)

    Kudryavtseva, V. L.; Zhuravlev, M. V.; Tverdokhlebov, S. I.

    2017-09-01

    A new approach for the modification of polylactic acid (PLA) materials using atmospheric pressure plasma (APP) is described. PLA films plasma exposure time was 20, 60, 120 s. The surface morphology and wettability of the obtained PLA films were investigated by atomic force microscopy (AFM) and the sitting drop method. The atmospheric pressure plasma increased the roughness and surface energy of PLA film. The wettability of PLA has been improved with the application of an atmospheric plasma surface treatment. It was shown that it is possible to obtain PLA films with various surface relief and tunable wettability. Additionally, we demonstrated that the use of cold atmospheric pressure plasma for surface activation allows for the immobilization of bioactive compounds like hyaluronic acid (HA) on the surface of obtained films. It was shown that composite PLA-HA films have an increased long-term hydrophilicity of the films surface.

  14. Surface modification of carbon/epoxy prepreg using oxygen plasma and its effect on the delamination resistance behavior of carbon/epoxy composites

    International Nuclear Information System (INIS)

    Kim, M.H.; Rhee, K.Y.; Kim, H.J.; Jung, D.H.

    2007-01-01

    It was shown in previous study that the fracture toughness of carbon/epoxy laminated composites could be significantly improved by modifying the surface of the prepreg using Ar + irradiation in an oxygen environment. In this study, the surface of carbon/epoxy prepreg was modified using an oxygen plasma to improve the delamination resistance behavior of carbon/epoxy laminated composites. The variation of the contact angle on the prepreg surface was determined as a function of the modification time, in order to determine the optimal modification time. An XPS analysis was conducted to investigate the chemical changes on the surface of the prepreg caused by the plasma modification. Mode I delamination resistance curves of the composites with and without surface modification were plotted as a function of the delamination increment. The results showed that the contact angle varied from ∼64 o to ∼47 o depending on the modification time and reached a minimum for a modification time of 30 min. The XPS analysis showed that the hydrophilic carbonyl C=O group was formed by the oxygen plasma modification. The results also showed that the delamination resistance behavior was significantly improved by the plasma modification of the prepreg. This improvement was caused by the better layer-to-layer adhesion as well as increased interfacial strength between the fibers and matrix

  15. Polyamide desalination membrane characterization and surface modification to enhance fouling resistance.

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mukul M. (Univeristy of Texas at Austin, Austin, TX); Freeman, Benny D. (Univeristy of Texas at Austin, Austin, TX); Van Wagner, Elizabeth M. (Univeristy of Texas at Austin, Austin, TX); Hickner, Michael A. (Pennsylvania State University, University Park, PA); Altman, Susan Jeanne

    2010-08-01

    The market for polyamide desalination membranes is expected to continue to grow during the coming decades. Purification of alternative water sources will also be necessary to meet growing water demands. Purification of produced water, a byproduct of oil and gas production, is of interest due to its dual potential to provide water for beneficial use as well as to reduce wastewater disposal costs. However, current polyamide membranes are prone to fouling, which decreases water flux and shortens membrane lifetime. This research explored surface modification using poly(ethylene glycol) diglycidyl ether (PEGDE) to improve the fouling resistance of commercial polyamide membranes. Characterization of commercial polyamide membrane performance was a necessary first step before undertaking surface modification studies. Membrane performance was found to be sensitive to crossflow testing conditions. Concentration polarization and feed pH strongly influenced NaCl rejection, and the use of continuous feed filtration led to higher water flux and lower NaCl rejection than was observed for similar tests performed using unfiltered feed. Two commercial polyamide membranes, including one reverse osmosis and one nanofiltration membrane, were modified by grafting PEGDE to their surfaces. Two different PEG molecular weights (200 and 1000) and treatment concentrations (1% (w/w) and 15% (w/w)) were studied. Water flux decreased and NaCl rejection increased with PEGDE graft density ({micro}g/cm{sup 2}), although the largest changes were observed for low PEGDE graft densities. Surface properties including hydrophilicity, roughness and charge were minimally affected by surface modification. The fouling resistance of modified and unmodified membranes was compared in crossflow filtration studies using model foulant solutions consisting of either a charged surfactant or an oil in water emulsion containing n-decane and a charged surfactant. Several PEGDE-modified membranes demonstrated improved

  16. Surface modification of polymeric substrates by plasma-based ion implantation

    Science.gov (United States)

    Okuji, S.; Sekiya, M.; Nakabayashi, M.; Endo, H.; Sakudo, N.; Nagai, K.

    2006-01-01

    Plasma-based ion implantation (PBII) as a tool for polymer modification is studied. Polymeric films have good performances for flexible use, such as food packaging or electronic devices. Compared with inorganic rigid materials, polymers generally have large permeability for gases and moisture, which causes packaged contents and devices to degrade. In order to add a barrier function, surface of polymeric films are modified by PBII. One of the advantageous features of this method over deposition is that the modified surface does not have peeling problem. Besides, micro-cracks due to mechanical stress in the modified layer can be decreased. From the standpoint of mass production, conventional ion implantation that needs low-pressure environment of less than 10-3 Pa is not suitable for continuous large-area processing, while PBII works at rather higher pressure of several Pa. In terms of issues mentioned above, PBII is one of the most expected techniques for modification on flexible substrates. However, the mechanism how the barrier function appears by ion implantation is not well explained so far. In this study, various kinds of polymeric films, including polyethyleneterephthalate (PET), are modified by PBII and their barrier characteristics that depend on the ion dose are evaluated. In order to investigate correlations of the barrier function with implanted ions, modified surface is analyzed with X-ray photoelectron spectroscopy (XPS). It is assumed that the diffusion and sorption coefficients are changed by ion implantation, resulting in higher barrier function.

  17. Surface modification of polymeric substrates by plasma-based ion implantation

    International Nuclear Information System (INIS)

    Okuji, S.; Sekiya, M.; Nakabayashi, M.; Endo, H.; Sakudo, N.; Nagai, K.

    2006-01-01

    Plasma-based ion implantation (PBII) as a tool for polymer modification is studied. Polymeric films have good performances for flexible use, such as food packaging or electronic devices. Compared with inorganic rigid materials, polymers generally have large permeability for gases and moisture, which causes packaged contents and devices to degrade. In order to add a barrier function, surface of polymeric films are modified by PBII. One of the advantageous features of this method over deposition is that the modified surface does not have peeling problem. Besides, micro-cracks due to mechanical stress in the modified layer can be decreased. From the standpoint of mass production, conventional ion implantation that needs low-pressure environment of less than 10 -3 Pa is not suitable for continuous large-area processing, while PBII works at rather higher pressure of several Pa. In terms of issues mentioned above, PBII is one of the most expected techniques for modification on flexible substrates. However, the mechanism how the barrier function appears by ion implantation is not well explained so far. In this study, various kinds of polymeric films, including polyethyleneterephthalate (PET), are modified by PBII and their barrier characteristics that depend on the ion dose are evaluated. In order to investigate correlations of the barrier function with implanted ions, modified surface is analyzed with X-ray photoelectron spectroscopy (XPS). It is assumed that the diffusion and sorption coefficients are changed by ion implantation, resulting in higher barrier function

  18. A bio-enabled maximally mild layer-by-layer Kapton surface modification approach for the fabrication of all-inkjet-printed flexible electronic devices

    Science.gov (United States)

    Fang, Yunnan; Hester, Jimmy G. D.; Su, Wenjing; Chow, Justin H.; Sitaraman, Suresh K.; Tentzeris, Manos M.

    2016-12-01

    A bio-enabled, environmentally-friendly, and maximally mild layer-by-layer approach has been developed to surface modify inherently hydrophobic Kapton HN substrates to allow for great printability of both water- and organic solvent-based inks thus facilitating the full-inkjet-printing of flexible electronic devices. Different from the traditional Kapton surface modification approaches which are structure-compromising and use harsh conditions to target, and oxidize and/or remove part of, the surface polyimide of Kapton, the present Kapton surface modification approach targeted the surface electric charges borne by its additive particles, and was not only the first to utilize environmentally-friendly clinical biomolecules to build up a thin film of protamine-heparin complex on Kapton, but also the first to be conducted under minimally destructive and maximally mild conditions. Besides, for electrically charged ink particles, the present surface modification method can enhance the uniformity of the inkjet-printed films by reducing the “coffee ring effect”. As a proof-of-concept demonstration, reduced graphene oxide-based gas sensors, which were flexible, ultra-lightweight, and miniature-sized, were fully-inkjet-printed on surface modified Kapton HN films and tested for their sensitivity to dimethyl methylphosphonate (a nerve agent simulant). Such fabricated sensors survived a Scotch-tape peel test and were found insensitive to repeated bending to a small 0.5 cm radius.

  19. Modification of a cyclo-olefin surface by radio-sterilization: is there any effect on the interaction with drug solutions?

    Science.gov (United States)

    Barakat, Hala; Saunier, Johanna; Aymes Chodur, Caroline; Aubert, Pascal; Vigneron, Jackie; Etcheberry, Arnaud; Yagoubi, Najet

    2013-11-01

    A cyclo-olefin copolymer was subjected to an e-beam ionizing treatment. Two doses were studied: one corresponding to the recommended dose for the sterilization of pharmaceutical packaging (25 kGy), and a greater one to enhance the modifications caused by the treatment (150 kGy). The surface modifications were studied by X-ray photoelectron spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM). The roughness and the wettability of the surface were enhanced by the treatment. The consequences of the surface modifications on the drug interaction with the polymer were studied. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Modification of transition's factor in the compact surface-potential-based MOSFET model

    Directory of Open Access Journals (Sweden)

    Kevkić Tijana

    2016-01-01

    Full Text Available The modification of an important transition's factor which enables continual behavior of the surface potential in entire useful range of MOSFET operation is presented. The various modifications have been made in order to obtain an accurate and computationally efficient compact MOSFET model. The best results have been achieved by introducing the generalized logistic function (GL in fitting of considered factor. The smoothness and speed of the transition of the surface potential from the depletion to the strong inversion region can be controlled in this way. The results of the explicit model with this GL functional form for transition's factor have been verified extensively with the numerical data. A great agreement was found for a wide range of substrate doping and oxide thickness. Moreover, the proposed approach can be also applied on the case where quantum mechanical effects play important role in inversion mode.

  1. Surface modification and characterization of aramid fibers with hybrid coating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianrui; Zhu, Yaofeng; Ni, Qingqing; Fu, Yaqin, E-mail: fyq01@zstu.edu.cn; Fu, Xiang

    2014-12-01

    Graphical abstract: - Highlights: • Aramid fibers modification sizing synthesized by sol–gel in the absence of water. • The strength and interfacial adhesion property of modified fibers were improved. • Modified fibers show a special surface structure. • The mechanism explains the function of structure. - Abstract: Aramid fibers were modified through solution dip-coating and interfacial in situ polymerization using a newly synthesized SiO{sub 2}/shape memory polyurethane (SiO{sub 2}/SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO{sub 2}/SMPU hybrid successfully coated the fiber surface. The surface morphology of the aramid fibers and the single fiber tensile strength and interfacial shear strength (IFSS) of the composites were determined. The IFSS of the fiber coated with the hybrid improved by 45%, which benefited from a special “pizza-like” structure on the fiber surface.

  2. Surface modification and characterization of aramid fibers with hybrid coating

    International Nuclear Information System (INIS)

    Chen, Jianrui; Zhu, Yaofeng; Ni, Qingqing; Fu, Yaqin; Fu, Xiang

    2014-01-01

    Graphical abstract: - Highlights: • Aramid fibers modification sizing synthesized by sol–gel in the absence of water. • The strength and interfacial adhesion property of modified fibers were improved. • Modified fibers show a special surface structure. • The mechanism explains the function of structure. - Abstract: Aramid fibers were modified through solution dip-coating and interfacial in situ polymerization using a newly synthesized SiO 2 /shape memory polyurethane (SiO 2 /SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO 2 /SMPU hybrid successfully coated the fiber surface. The surface morphology of the aramid fibers and the single fiber tensile strength and interfacial shear strength (IFSS) of the composites were determined. The IFSS of the fiber coated with the hybrid improved by 45%, which benefited from a special “pizza-like” structure on the fiber surface

  3. Enhanced osteointegration of medical titanium implant with surface modifications in micro/nanoscale structures

    Directory of Open Access Journals (Sweden)

    Liwen Lin

    2014-01-01

    Full Text Available Biomimetic design and substrate-based surface modification of medical implants will help to improve the integration of tissue to its material interfaces. Surface energy, composition, roughness, and topography all influence the biological responses of the implants, such as protein adsorption and cell adhesion, proliferation and differentiation. In the current study, different surface structures of Ti implants were constructed using facile surface techniques to create various micro-, nano-, and nano/micro composite scale topography. We have fabricated three types of hierarchical structures of TiO2 coating on Ti implants, including nanotube structure, nano sponge-like structure, and nano/micro nest-like structure. The osteointegration and biomechanical performance of the coated Ti screws were evaluated by histology and removal of torque force test in vivo. We found that the nano/micro nest-like and nanotube structured surface possessed better osteointegration ability. It indicated that the alkaline hydrothermally treated Ti substrate was the best for bone-implant integration in terms of all in vitro and in vivo testing parameters. The alkaline hydrothermally treated surface displayed a hydrophilic (contact angle value 5.92 ± 1.2, higher roughness (Ra value 911.3 ± 33.8 nm, higher specific surface area (8.26 ± 1.051 m2/g, and greater apatite inductivity. The electrochemical surface modification may become a powerful approach to enhance metal implant to bone integration in orthopaedic applications.

  4. Laser surface modification of polyethersulfone films: effect of laser wavelength on biocompatibility

    International Nuclear Information System (INIS)

    Pazokian, H; Jelvani, S; Mollabashi, M; Barzin, J

    2013-01-01

    In this paper laser ablation of polyethersulfone (PES) films regarding to the change in biocompatibility of the surface is investigated at 3 different wavelengths of 193nm (ArF), 248 nm (KrF) and 308 nm (XeCl). The optimum laser fluence and number of pulses for the improvement of the surface biocompatibility is found by examination of the surface behavior in contact with platelets and fibroblasts cells at 3 wavelengths. These biological modifications are explained by alteration of the surface morphology and chemistry following irradiation. The results show that the KrF laser is the best choice for treatment of PES in biological applications.

  5. Enhanced surface modification engineering (H, F, Cl, Br, and NO{sub 2}) of CdS nanowires with and without surface dangling bonds

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yijie; Xing, Huaizhong, E-mail: xinghz@dhu.edu.cn; Lu, Aijiang; Wang, Chunrui; Xu, Xiaofeng [Department of Applied Physics and State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Ren Min Road 2999, Songjiang District, Shanghai 201620 (China); Huang, Yan; Chen, Xiaoshuang, E-mail: jqwang@ee.ecnu.edu.cn, E-mail: xschen@mail.sitp.ac.cn [National Lab. of Infrared Physics, Shanghai Institute for Technical Physics, Chinese Academy of Science, 500 Yu Tian Road, Shanghai 200083 (China); Wang, Jiqing, E-mail: jqwang@ee.ecnu.edu.cn, E-mail: xschen@mail.sitp.ac.cn [Key Laboratory of Polarized Materials and Devices, East China Normal University, Shanghai 200062 (China)

    2015-08-07

    Semiconductor nanowires (NWs) can be applied in gas sensing and cell detection, but the sensing mechanism is not clearly understood. In this study, surface modification effect on the electronic properties of CdS NWs for different diameters with several species (H, F, Cl, Br, and NO{sub 2}) is investigated by first principles calculations. The surface dangling bonds and halogen elements are chosen to represent the environment of the surface. Halogen passivation drastically changes the band gaps due to the strong electronegativity and the energy level of halogen atoms. Density of states analysis indicates that valence band maximum (VBM) of halogen-passivated NWs is formed by the p states of halogen atoms, while VBM of H-passivated NWs is originated from Cd 4d and S 3p orbitals. To illustrate that surface modification can be applied in gas sensing, NO{sub 2}-absorbed NWs with different coverage are calculated. Low coverage of NO{sub 2} introduces a deep p-type dopant-like level, while high coverage introduces a shallow n-type dopant-like level into the band structure. The transformation is due to that at low coverage the adsorption is chemical while at high coverage is physical. These findings might promote the understanding of surface modification effect and the sensing mechanism of NWs as gas sensors.

  6. Redirecting adenovirus tropism by genetic, chemical, and mechanical modification of the adenovirus surface for cancer gene therapy.

    Science.gov (United States)

    Yoon, A-Rum; Hong, Jinwoo; Kim, Sung Wan; Yun, Chae-Ok

    2016-06-01

    Despite remarkable advancements, clinical evaluations of adenovirus (Ad)-mediated cancer gene therapies have highlighted the need for improved delivery and targeting. Genetic modification of Ad capsid proteins has been extensively attempted. Although genetic modification enhances the therapeutic potential of Ad, it is difficult to successfully incorporate extraneous moieties into the capsid and the engineering process is laborious. Recently, chemical modification of the Ad surface with nanomaterials and targeting moieties has been found to enhance Ad internalization into the target by both passive and active mechanisms. Alternatively, external stimulus-mediated targeting can result in selective accumulation of Ad in the tumor and prevent dissemination of Ad into surrounding nontarget tissues. In the present review, we discuss various genetic, chemical, and mechanical engineering strategies for overcoming the challenges that hinder the therapeutic efficacy of Ad-based approaches. Surface modification of Ad by genetic, chemical, or mechanical engineering strategies enables Ad to overcome the shortcomings of conventional Ad and enhances delivery efficiency through distinct and unique mechanisms that unmodified Ad cannot mimic. However, although the therapeutic potential of Ad-mediated gene therapy has been enhanced by various surface modification strategies, each strategy still possesses innate limitations that must be addressed, requiring innovative ideas and designs.

  7. Microwave plasma initiated graft copolymerization modification of monomers onto PTFE surface

    International Nuclear Information System (INIS)

    Guan Weishu; Wen Yunjian; Fang Yan; Yin Yongxiang

    1996-02-01

    A graft copolymerization modification technique of monomers onto polytetrafluoroethylene (PTFE) surface initiated by a 2.45 GHz non-equilibrium microwave plasma has been investigated. Standard X-Ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (sEM) and wetting techniques were used for examination and analysis of samples. Considerable changes in chemical structure, composition and in morphology of grafted surface of PTFE were found. Results showed the occurrence of noticeable defluorination and cross-linked structure on grafted surface, and indicated that different kinds and contents of oxygen-containing functional groups were introduced into the surface of PTFE. Wetting and adhesion experiment of the sample proved that significant improvements in hydrophilicity and adhesion of surface were exhibited. These results confirmed the success of grafting. (8 refs., 7 figs., 1 tab.)

  8. Surface modification of TA2 pure titanium by low energy high current pulsed electron beam treatments

    International Nuclear Information System (INIS)

    Gao Yukui

    2011-01-01

    Surface integrity changes of TA2 pure titanium including surface topography, microstructure and nanohardness distribution along surface layer were investigated by different techniques of low energy high current pulsed electron beam treatments (LEHCPEBTs). The surface topography was characterized by SEM. Moreover, the TEM observation and X-ray diffraction analysis were performed to reveal the surface modification mechanism of TA2 pure titanium by LEHCPEBTs. The surface roughness was modified by electron beam treatment and the polishing mechanism was analyzed by studying the cross section microstructure of electron beam treated specimens by SEM and TEM. The results show that the surface finish obtains good polishing quality and there is no phase transformation but the dislocations by LEHCPEBT. Furthermore, the nanohardness in the surface modified layer is improved. The remelt and fine-grain microstructure of surface layer caused by LEHCPEBTs are the main polishing mechanism and the reason of modification of surface topography and the increment in nanohardness is mainly due to the dislocations and fine grains in the modified layer induced by LEHCPEBT.

  9. Plasma immersion surface modification with metal ion plasma

    International Nuclear Information System (INIS)

    Brown, I.G.; Yu, K.M.; Godechot, X.

    1991-04-01

    We describe here a novel technique for surface modification in which metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including' conventional' high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way. 22 refs., 4 figs

  10. Comparative studies of biological activity of cadmium-based quantum dots with different surface modifications

    Science.gov (United States)

    Kalinowska, D.; Grabowska-Jadach, I.; Drozd, M.; Pietrzak, M.

    2018-05-01

    This paper presents a modification of the surface of CdS/ZnS and CdSe x S1-x /ZnS quantum dots (QDs) with 3-mercaptopropionic and 6-mercaptohexanoic acid. The obtained QDs were characterized using TEM, DLS, UV-Vis, and fluorescence spectroscopy. Flow cytometry was applied to evaluate the cytotoxicity of QDs and examine the type of death caused by the tested nanoparticles. In addition, the generation of reactive oxygen species after incubation of the tested cells with CdSe x S1-x /ZnS-MPA and CdSe x S1-x /ZnS-MHA QDs was evaluated. The study was conducted on three cell lines: adherent (A549 and MRC-5) and suspension ones (K562). The conducted research demonstrated that the tested nanoparticles exhibit concentration-dependent toxicity. It was observed that the surface modification influences the toxicity level of the examined QDs, and modification of their surface with the use of the ligand of longer carbon chain (MHA) reduces the toxicity in comparison with QDs-MPA. It was also found that all tested QDs caused the death of cells in the course of necrosis. Based on obtained results, it was concluded that the cytotoxicity of QDs is to a large extent related to reactive oxygen species (ROS) generation.

  11. Nanoscale surface modification for enhanced biosensing a journey toward better glucose monitoring

    CERN Document Server

    Zhang, Guigen

    2015-01-01

    This book gives a comprehensive overview of electrochemical-based biosensors and their crucial components. Practical examples are given throughout the text to illustrate how the performance of electrochemical-based biosensors can be improved by nanoscale surface modification and how an optimal design can be achieved. All essential aspects of biosensors are considered, including electrode functionalization, efficiency of the mass transport of reactive species, and long term durability and functionality of the sensor. This book also: ·       Explains how the performance of an electrochemical-based biosensor can be improved by nanoscale surface modification ·       Gives readers the tools to evaluate and improve the performance of a biosensor with a multidisciplinary approach that considers electrical, electrostatic, electrochemical, chemical, and biochemical events ·       Links the performance of a sensor to the various governing physical and chemical principles so readers can fully unders...

  12. Influence of DC plasma modification on the selected properties and the geometrical surface structure of polylactide prior to autocatalytic metallization

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Kazimierz Wielki University, Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, Marii Skłodowskiej-Curie 55, 87-100 Toruń (Poland); Tracz, Adam [Centre for Molecular and Macromolecular Studies of the Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź (Poland); Żenkiewicz, Marian [Institute for Engineering of Polymer Materials and Dyes, Marii Skłodowskiej-Curie 55, 87-100 Toruń (Poland)

    2015-03-01

    The paper presents the results of studies to determine the applicability of plasma modification in the process of polylactide (PLA) surface preparation prior to the autocatalytic metallization. The polylactide plasma modification was carried out in an oxygen or nitrogen chemistry. The samples were tested with the following methods: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and electron spectrophotometry (XPS). Scanning electron microscopy and atomic force microscopy images were demonstrated. The results of surface free energy calculations, performed based on the results of the contact angle measurements have been presented. The results of the qualitative (degree of oxidation or nitridation) and quantitative analysis of the chemical composition of the polylactide surface layer have also been described. The results of the studies show that the DC plasma modification performed in the proposed condition is a suitable as a method of surface preparation for the polylactide metallization. - Highlights: • We modified polylactide surface layer with plasma generated in oxygen or nitrogen. • We tested selected properties and surface structure of modified samples. • DC plasma modification can be used to prepare the PLA surface for metallization. • For better results metallization should be preceded by sonication process.

  13. Plasma based Ar+ beam assisted poly(dimethylsiloxane) surface modification

    International Nuclear Information System (INIS)

    Vladkova, T.G.; Keranov, I.L.; Dineff, P.D.; Youroukov, S.Y.; Avramova, I.A.; Krasteva, N.; Altankov, G.P.

    2005-01-01

    Plasma based Ar + beam performed in RF (13.56 MHz) low-pressure (200 mTorr) glow discharge (at 100 W, 1200 W and 2500 W) with a serial capacitance was employed for surface modification of poly(dimethylsiloxane) (PDMS) aimed at improvement of its interactions with living cells. The presence of a serial capacitance ensures arise of an ion-flow inside the plasma volume directed toward the treated sample and the vary of the discharge power ensures varied density of the ion-flow. XPS analysis was performed to study the changes in the surface chemical composition of the modified samples and the corresponding changes in the surface energy were monitored by contact angle measurements. We found that plasma based Ar + beam transforms the initially hydrophobic PDMS surface into a hydrophilic one mainly due to a raising of the polar component of the surface tension, this effect being most probably due to an enrichment of the modified surface layer with permanent dipoles of a [SiO x ]-based network and elimination of the original methyl groups. The initial adhesion of human fibroblast cells was studied on the described above plasma based Ar + beam modified and acrylic acid (AA) grafted or not fibronectin (FN) pre-coated or bare surfaces. The cell response seems to be related with the peculiar structure and wettability of the modified PDMS surface layer after plasma based Ar + beam treatment followed or not by AA grafting

  14. Roughness modification of surfaces treated by a pulsed dielectric barrier discharge

    CERN Document Server

    Dumitrascu, N; Apetroaei, N; Popa, G

    2002-01-01

    Local modifications of surface roughness are very important in many applications, as this surface property is able to generate new mechano-physical characteristics of a large category of materials. Roughness is one of the most important parameters used to characterize and control the surface morphology, and techniques that allow modifying and controlling the surface roughness present increasing interest. In this respect we propose the dielectric barrier discharge (DBD) as a simple and low cost method that can be used to induce controlled roughness on various surfaces in the nanoscale range. DBD is produced in helium, at atmospheric pressure, by a pulsed high voltage, 28 kV peak to peak, 13.5 kHz frequency and 40 W power. This type of discharge is a source of energy capable of modifying the physico-chemical properties of the surfaces without affecting their bulk properties. The discharge is characterized by means of electrical probes and, in order to analyse the heat transfer rate from the discharge to the tre...

  15. Investigation of graft copolymerization modification of PTFE surface using microwave plasma

    International Nuclear Information System (INIS)

    Wen Yunjian; Guan Weishu; Fang Yan; Ying Yongxiang

    1995-03-01

    Investigation of graft copolymerization modification of PTFE surface with kind of one or another reactive monomers was performed by using non-equilibrium microwave plasma at 2.45 GHz under various operating conditions. Untreated clean samples and grafted samples were examined and analyzed with different surface analytical techniques such as X-Ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscopy (SEM). The results showed that the occurrence of noticeable de-fluorination and cross linking on grafted surface, and different polar groups and content of oxygen-containing were introduced into the grafted surface of PTFE. Fibriform hetero-structure layer was also formed. These results confirmed the success of graft and indicated that the hydrophilicity of the grafted surface is excellent and a significant improvement in adhesion characteristics has been achieved. The experiments revealed that the changes in surface properties are correlated closely to the changes in chemical structure, composition and morphology. (8 figs., 1 refs.)

  16. Effective modification of particle surface properties using ultrasonic water mist

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

    2009-01-01

    The goal of the present study was to design a new technique to modify particle surface properties and, through that, to improve flowability of poorly flowing drug thiamine hydrochloride and pharmaceutical sugar lactose monohydrate of two different grades. The powdered particles were supplied...... properties. It was found that rapid exposition of pharmaceutical materials by water mist resulted in the improvement of powder technical properties. The evident changes in flowability of coarser lactose were obviously due to smoothing of particle surface and decreasing in the level of fines with very slight...... increment in particle size. The changes in thiamine powder flow were mainly due to narrowing in particle size distribution where the tendency for better flow of finer lactose was related to surface and size modifications. The aqueous mist application did not cause any alteration of the crystal structures...

  17. Evaluation of electrode surface modification techniques for the development of chemical sensors

    International Nuclear Information System (INIS)

    Galiatsatos, C.

    1988-01-01

    This thesis covers several aspects of electrode surface modification techniques. The successful application of gamma-radiation to create polymer-coated electrodes, where the polymers can be ion exchangers and consequently of great analytical interest by themselves (such as the polymer poly(diallyl) dimethyl ammonium chloride) or where some other neutral polymers can function as convenient matrices for the introduction of biomolecules and/or other electrochemically interesting species is reported. This is demonstrated by using the neutral polymer poly(vinyl alcohol) (PVAL) as a matrix for immobilization of the enzyme glucose oxidase and the mediator methyl viologen. The effect of γ-radiation on PVAL is discussed, as well as swelling properties of the irradiated polymers and specific characteristics of the created chemical sensors. Results of an experiment where the various kinds of interactions between the ion-exchange polymer Nafion and some positively charged species are explored are reported, and a model system for competition (methyl viologen vs. ruthenium hexaamine) which increases significantly our understanding of the interaction is mentioned. The effect of γ-radiation on Nafion and its ion-exchange compabilities is discussed also. A system of conduction polymers primarily polypyrrole, used as a detector of electroinactive anions due to their doping-undergoing in the film is discussed. Preliminary results on a new method that involves chemical cross-linking of a triisocyane molecule with -OH containing polymers in the presence of enzymes are reported

  18. Preparation of poly(2-chloroaniline) membrane and plasma surface modification

    International Nuclear Information System (INIS)

    Kir, E.; Oksuz, L.; Helhel, S.

    2006-01-01

    P2ClAn membranes were obtained from chemically synthesized poly(2-chloroaniline) (P2ClAn) by casting method. These membranes were cast from dimethyl formamide (DMF) and were in the undoped state. P2ClAn membranes were characterized by Fourier infrared spectroscopy and scanning electron microscopy. Measurements of water content capacity, membrane thickness and ion-exchange capacity of the cast membranes were carried out. P2ClAn membranes were treated by electron cylotron resonance (ECR) plasma for surface modification. Plasma treatment has been successfully utilized for improving the surface properties of P2ClAn membranes such as increasing pore diameters and number of pores for better anion or molecule transportation

  19. Polypropylene non-woven fabric membrane via surface modification with biomimetic phosphorylcholine in Ce(IV)/HNO{sub 3} redox system

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Jie; Shi Qiang; Luan Shifang; Song Lingjie; Yang Huawei [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-10-01

    Surface modification of polypropylene non-woven fabric membrane (NWF) for improving its hemocompatibility was developed by grafting a biomimic monomer, 2-methacryloyloxyethyl phosphorycholine (MPC). The NWF membrane surface was first activated by potassium peroxydisulfate to form hydroxyl groups, and then grafted with MPC using ceric (IV) ammonium nitrate as the redox initiator. The surface chemical changes before and after modification were confirmed by Fourier transform infrared spectroscopy with an ATR unit (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS); the water contact angle results showed the gradual changes in wettability from hydrophobic to hydrophilic surface. Meanwhile, the hemocompatibility of these samples was also evaluated by protein adsorption and platelet adhesion. These experimental results exhibited that the introduction of poly(MPC) onto the NWF membrane surfaces substantially improved their hemocompatibility. The feasibility and simplicity of this procedure may lead to potential applications of NWF membranes in biomedical separation and blood purification. - Graphical abstract: 2-methacryloyloxyethyl phosphorycholine (MPC), was grafted onto non-woven fabric (NWF) membrane surface by Ce(IV)/HNO{sub 3} redox system. The protein adsorption and platelet adhesion were substantially suppressed by the introduction of poly(MPC). Highlights: Black-Right-Pointing-Pointer MPC was successfully grafted onto NWF PP membrane surface. Black-Right-Pointing-Pointer Obviously enhanced hemocompatibility was acquired by the modified samples. Black-Right-Pointing-Pointer A facile redox grafting was adopted in the whole process.

  20. Surface modification of polycaprolactone scaffolds fabricated via selective laser sintering for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Chen, Chih-Hao; Lee, Ming-Yih; Shyu, Victor Bong-Hang; Chen, Yi-Chieh; Chen, Chien-Tzung; Chen, Jyh-Ping

    2014-01-01

    Surface modified porous polycaprolactone scaffolds fabricated via rapid prototyping techniques were evaluated for cartilage tissue engineering purposes. Polycaprolactone scaffolds manufactured by selective laser sintering (SLS) were surface modified through immersion coating with either gelatin or collagen. Three groups of scaffolds were created and compared for both mechanical and biological properties. Surface modification with collagen or gelatin improved the hydrophilicity, water uptake and mechanical strength of the pristine scaffold. From microscopic observations and biochemical analysis, collagen-modified scaffold was the best for cartilage tissue engineering in terms of cell proliferation and extracellular matrix production. Chondrocytes/collagen-modified scaffold constructs were implanted subdermally in the dorsal spaces of female nude mice. Histological and immunohistochemical staining of the retrieved implants after 8 weeks revealed enhanced cartilage tissue formation. We conclude that collagen surface modification through immersion coating on SLS-manufactured scaffolds is a feasible scaffold for cartilage tissue engineering in craniofacial reconstruction. - Highlights: • Selective laser sintered polycaprolactone scaffolds are prepared. • Scaffolds are surface modified through immersion coating with gelatin or collagen. • Collagen-scaffold is the best for cartilage tissue engineering in vitro. • Chondrocytes/collagen-scaffold reveals enhanced cartilage tissue formation in vivo

  1. Surface modification of polycaprolactone scaffolds fabricated via selective laser sintering for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chih-Hao [Department of Chemical and Materials Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan, ROC (China); Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Craniofacial Research Center, Chang Gung University, Kweishann, Taoyuan 333, Taiwan, ROC (China); Lee, Ming-Yih [Graduate Institute of Medical Mechatronics, Chang Gung University, Kweishan, Taoyuan 333, Taiwan, ROC (China); Shyu, Victor Bong-Hang; Chen, Yi-Chieh; Chen, Chien-Tzung [Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Craniofacial Research Center, Chang Gung University, Kweishann, Taoyuan 333, Taiwan, ROC (China); Chen, Jyh-Ping, E-mail: jpchen@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan, ROC (China); Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Kweishan, Taoyuan 333, Taiwan, ROC (China)

    2014-07-01

    Surface modified porous polycaprolactone scaffolds fabricated via rapid prototyping techniques were evaluated for cartilage tissue engineering purposes. Polycaprolactone scaffolds manufactured by selective laser sintering (SLS) were surface modified through immersion coating with either gelatin or collagen. Three groups of scaffolds were created and compared for both mechanical and biological properties. Surface modification with collagen or gelatin improved the hydrophilicity, water uptake and mechanical strength of the pristine scaffold. From microscopic observations and biochemical analysis, collagen-modified scaffold was the best for cartilage tissue engineering in terms of cell proliferation and extracellular matrix production. Chondrocytes/collagen-modified scaffold constructs were implanted subdermally in the dorsal spaces of female nude mice. Histological and immunohistochemical staining of the retrieved implants after 8 weeks revealed enhanced cartilage tissue formation. We conclude that collagen surface modification through immersion coating on SLS-manufactured scaffolds is a feasible scaffold for cartilage tissue engineering in craniofacial reconstruction. - Highlights: • Selective laser sintered polycaprolactone scaffolds are prepared. • Scaffolds are surface modified through immersion coating with gelatin or collagen. • Collagen-scaffold is the best for cartilage tissue engineering in vitro. • Chondrocytes/collagen-scaffold reveals enhanced cartilage tissue formation in vivo.

  2. Surface Modification of Solution-Processed ZrO2 Films through Double Coating for Pentacene Thin-Film Transistors

    Science.gov (United States)

    Kwon, Jin-Hyuk; Bae, Jin-Hyuk; Lee, Hyeonju; Park, Jaehoon

    2018-03-01

    We report the modification of surface properties of solution-processed zirconium oxide (ZrO2) dielectric films achieved by using double-coating process. It is proven that the surface properties of the ZrO2 film are modified through the double-coating process; the surface roughness decreases and the surface energy increases. The present surface modification of the ZrO2 film contributes to an increase in grain size of the pentacene film, thereby increasing the field-effect mobility and decreasing the threshold voltage of the pentacene thin-film transistors (TFTs) having the ZrO2 gate dielectric. Herein, the molecular orientation of pentacene film is also studied based on the results of contact angle and X-ray diffraction measurements. Pentacene molecules on the double-coated ZrO2 film are found to be more tilted than those on the single-coated ZrO2 film, which is attributed to the surface modification of the ZrO2 film. However, no significant differences are observed in insulating properties between the single-and the double-coated ZrO2 dielectric films. Consequently, the characteristic improvements of the pentacene TFTs with the double-coated ZrO2 gate dielectric film can be understood through the increase in pentacene grain size and the reduction in grain boundary density.

  3. Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles

    Directory of Open Access Journals (Sweden)

    Wiśniewska-Weinert H.

    2015-09-01

    Full Text Available A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano- and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear characteristics of the sleeves and to determine the influence of sealing of the sliding interface on these characteristics. It is found that application of WS2 sold lubricant nano- and micro-particles and preservation of a particle leakage out of interface allows to achieve at the high temperature the friction coefficients comparable to those at ambient temperature.

  4. Surface modification and functionalization of metal and metal oxide nanoparticles by organic ligands

    NARCIS (Netherlands)

    Neouze, M.A.; Schubert, U.S.

    2008-01-01

    Metal or metal oxide nanoparticles possess unique features compared to equivalent larger-scale materials. For applications, it is often necessary to stabilize or functionalize such nanoparticles. Thus, modification of the surface of nanoparticles is an important chemical challenge. In this survey,

  5. Effect of Electropulsing-Assisted Ultrasonic Nanocrystalline Surface Modification on the Surface Mechanical Properties and Microstructure of Ti-6Al-4V Alloy

    Science.gov (United States)

    Ye, Yongda; Wang, Haibo; Tang, Guoyi; Song, Guolin

    2018-05-01

    The effect of electropulsing-assisted ultrasonic nanocrystalline surface modification (EP-UNSM) on surface mechanical properties and microstructure of Ti-6Al-4V alloy is investigated. Compared to conventional ultrasonic nanocrystalline surface modification (UNSM), EP-UNSM can effectively facilitate surface roughness and morphology, leading to excellent surface roughness (reduced from Ra 0.918 to Ra 0.028 μm by UNSM and Ra 0.019 μm by EP-UNSM) and smoother morphology with less cracks and defects. Surface friction coefficients are enhanced, resulting in lower and smoother friction coefficients. In addition, the surface-strengthened layer and ultra-refined grains are significantly enhanced with more severe plastic deformation and a greater surface hardness (a maximum hardness value of 407 HV and an effective depth of 550 μm, in comparison with the maximum hardness value of 364 HV and effective depth of 300 μm obtained by conventional UNSM). Remarkable enhancement of surface mechanical properties can be attributed to the refined gradient microstructure and the enhanced severe plastic deformation layer induced by coupling the effects of UNSM and electropulsing. The accelerated dislocation mobility and atom diffusion caused by the thermal and athermal effects of electropulsing treatment may be the primary intrinsic reasons for these improvements.

  6. Surface modification and electrochemical properties of activated carbons for supercapacitor electrodes

    Science.gov (United States)

    Yang, Dan; Qiu, Wenmei; Xu, Jingcai; Han, Yanbing; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Hong, Bo; Li, Ji; Ge, Hongliang; Wang, Xinqing

    2015-12-01

    Modifications with different acids (HNO3, H2SO4, HCl and HF, respectively) were introduced to treat the activated carbons (ACs) surface. The microstructures and surface chemical properties were discussed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), ASAP, Raman spectra and Fourier transform infrared (FTIR) spectra. The ACs electrode-based supercapacitors were assembled with 6 mol ṡ L-1 KOH electrolyte. The electrochemical properties were studied by galvanostatic charge-discharge and cyclic voltammetry. The results indicated that although the BET surface area of modified ACs decreased, the functional groups were introduced and the ash contents were reduced on the surface of ACs, receiving larger specific capacitance to initial AC. The specific capacitance of ACs modified with HCl, H2SO4, HF and HNO3 increased by 31.4%, 23%, 21% and 11.6%, respectively.

  7. Surface modification of an epoxy resin with polyamines and polydopamine: Adhesion toward electroless deposited copper

    Energy Technology Data Exchange (ETDEWEB)

    Schaubroeck, David, E-mail: David.Schaubroeck@elis.ugent.be [Center for Microsystems Technology (CMST), IMEC and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium); Mader, Lothar [Center for Microsystems Technology (CMST), IMEC and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium); Dubruel, Peter [Polymer Chemistry and Biomaterials Research Group, Ghent University, Krijgslaan 281 S4 bis, B-9000 Ghent (Belgium); Vanfleteren, Jan [Center for Microsystems Technology (CMST), IMEC and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium)

    2015-10-30

    Highlights: • Surface modifications of epoxy resins with polydopamine and grafted polyamines can significantly increase the adhesion toward electroless deposited copper. • A clear characterization of the copper/epoxy interphase is provided by SEM analyses of cross sections. • Tailored conditions such as etching time (roughness) and electroless deposition temperature are needed to increase the adhesion of the modified surfaces. - Abstract: In this paper the influence of the epoxy roughness, surface modifications and ELD (electroless copper deposition) temperatures on the adhesive strength of the copper is studied. Good adhesion at low roughness values is targeted due to their applicability in high density electronic circuits. Roughened epoxy surfaces are modified with adsorbed polyamines, polydopamine and polyamines grafted to polydopamine. Next the, adhesive strength of ELD copper is determined with peel strength measurements and the interphases are examined with SEM (scanning electron microscopy). Polydopamine and polyamines grafted to polydopamine can lead to increased adhesive strength at lower roughness values compared to the non-modified samples at specific plating temperatures.

  8. Hydrophobic modification of wood via surface-initiated ARGET ATRP of MMA

    Energy Technology Data Exchange (ETDEWEB)

    Fu Yanchun; Li Gang [Material Science and Engineering College, Northeast Forestry University, Harbin 150040 (China); Yu Haipeng, E-mail: yuhaipeng20000@yahoo.com.cn [Key laboratory of Bio-based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Material Science and Engineering College, Northeast Forestry University, Harbin 150040 (China); Liu Yixing, E-mail: yxl200488@sina.com [Key laboratory of Bio-based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Material Science and Engineering College, Northeast Forestry University, Harbin 150040 (China)

    2012-01-15

    To convert the hydrophilic surface of wood into a hydrophobic surface, the present study investigated activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) as a method of grafting methyl methacrylate (MMA) onto the wood surface. The wood treated with 2-bromoisobutyryl bromide and with the subsequently attached MMA via ARGET ATRP under different polymerization times (2 h, 4 h, 6 h, 8 h) were examined using scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. All the analyses confirmed that PMMA had been grafted onto the wood surface. Water contact angle measurement proved that the covering layer of PMMA on wood made the surface hydrophobic. Polymerization time had a positive influence on the contact angle value and higher contact angle can be produced with the prolongation of the polymerization time. When the reaction time was extended to 8 h, the contact angle of treated wood surface reached 130 Degree-Sign in the beginning, and remained at 116 Degree-Sign after 60 s. The ARGET ATRP method may raise an alteration on the wood surface modification.

  9. Surface modifications induced by hydrogen in AISI 304 stainless steel

    International Nuclear Information System (INIS)

    Evangelista, G.E.; Miranda, P.E.V. de

    1983-01-01

    Hydrogen induced surface modifications of type AISI 304 SS were studied by charging the samples in a 1N a 1N H 2 SO 4 electrolyte at room temperature. Current densities were varied from 500 to 4000 A/m 2 and charging times from 2 to 50 hours. Charged specimens were analysed using optical and electron scanning microscopy. Vickers microhardness tests with small load was also performed. Metallographic etching metodologies were developed (in black and white and colored photographies) which permited identification of all phases present. It was shown that delayed cracks appear somewhat curved on austenite and perfectly strainght on martensite, following the intersections of a phase platlets. These are the regions where α' martensite is located. The habit plane of these cracks might belong to (100) sub(γ) or (221) sub(γ) plane families. A new phenomenon termed hydrogen induced softening was observed on type AISI 304 SS at elevated current densities and/or charging times. (Author) [pt

  10. Preparation of Robust Superhydrophobic Halloysite Clay Nanotubes via Mussel-Inspired Surface Modification

    Directory of Open Access Journals (Sweden)

    Yang Meng

    2017-11-01

    Full Text Available In this study, a novel and convenient bio-inspired modification strategy was used to create stable superhydrophobic structures on halloysite clay nanotubes (HNTs surfaces. The polydopamine (PDA nanoparticles can firmly adhere on HNTs surfaces in a mail environment of pH 8.5 via the oxidative self-polymerization of dopamine and synthesize a rough nano-layer assisted with vitamin M, which provides a catechol functional platform for the secondary reaction to graft hydrophobic long-chain alkylamine for preparation of hierarchical micro/nano structures with superhydrophobic properties. The micromorphology, crystal structure, and surface chemical composition of the resultant superhydrophobic HNTs were characterized by field emission scanning electron (FE-SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and X-ray photoelectron spectroscopy (XPS. The as-formed surfaces exhibited outstanding superhydrophobicity with a water contact angle (CA of 156.3 ± 2.3°, while having little effect on the crystal structures of HNTs. Meanwhile, the resultant HNTs also showed robust stability that can conquer various harsh conditions including strong acidic/alkaline solutions, organic solvents, water boiling, ultrasonic cleaning, and outdoor solar radiation. In addition, the novel HNTs exhibited excellent packaged capabilities of phase change materials (PCMs for practical application in thermal energy storage, which improved the mass fractions by 22.94% for stearic acid and showed good recyclability. These HNTs also exhibited good oil/water separation ability. Consequently, due to the superior merits of high efficiency, easy operation, and non-toxicity, this bionic surface modification approach may make HNTs have great potentials for extensive applications.

  11. Applications of Functional Amyloids from Fungi: Surface Modification by Class I Hydrophobins

    Directory of Open Access Journals (Sweden)

    Alessandra Piscitelli

    2017-06-01

    Full Text Available Class I hydrophobins produced from fungi are amongst the first proteins recognized as functional amyloids. They are amphiphilic proteins involved in the formation of aerial structures such as spores or fruiting bodies. They form chemically robust layers which can only be dissolved in strong acids. These layers adhere to different surfaces, changing their wettability, and allow the binding of other proteins. Herein, the modification of diverse types of surfaces with Class I hydrophobins is reported, highlighting the applications of the coated surfaces. Indeed, these coatings can be exploited in several fields, spanning from biomedical to industrial applications, which include biosensing and textile manufacturing.

  12. Effects of Surface Modification of MWCNT on the Mechanical and Electrical Properties of Fluoro Elastomer/MWCNT Nanocomposites

    Directory of Open Access Journals (Sweden)

    Tao Xu

    2012-01-01

    Full Text Available Surface modification is a good way to improve the surface activity and interfacial strength of multiwalled carbon nanotubes (MWCNTs when used as fillers in the polymer composites. Among the reported methods for nanotube modification, mixed acid oxidation and plasma treatment is often used by introducing polar groups to the sidewall of MWCNT successfully. The purpose of this study is to evaluate the effect of different surface modification of MWCNT on the mechanical property and electrical conductivity of Fluoro-elastomer (FE/MWCNT nanocomposites. MWCNTs were surface modified by mixed oxidation and CF4 plasma treatment and then used to reinforce the fluoro elastomer (FE, a copolymer of trifluorochloroethylene and polyvinylidene fluoride. FE/MWCNT composite films were prepared from mixture solutions of ethylacetate and butylacetate, using untreated CNTs (UCNTs, acid-modified CNTs (ACNTs, and CF4 plasma-modified CNT (FCNTs. In each case, MWCNT content was 0.01 wt%, 0.05 wt%, 0.1 wt%, and 0.2 wt% with respect to the polymer. Morphology and mechanical properties were characterized by using scanning electron microscopy (SEM, Raman spectroscopy, as well as dynamic mechanical tests. The SEM results indicated that dispersion of ACNTs and especially FCNTs in FE was better than that of UCNTs. DMA indicated mechanical properties of FCNT composites were improved over ACNT and UCNT filled FE. The resulting electrical properties of the composites ranged from dielectric behavior to bulk conductivities of 10-2 Sm-1 and were found to depend strongly on the surface modification methods of MWCNTs.

  13. Plasma modification of polypropylene surfaces and its alloying with styrene in situ

    Energy Technology Data Exchange (ETDEWEB)

    Ma Guiqiu, E-mail: magq@tju.edu.cn [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China); Liu Ben; Li Chen; Huang Dinghai; Sheng Jing [School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 (China)

    2012-01-15

    The treatment of polypropylene surfaces has been studied by dielectric barrier discharges plasma of Ar. The structure and morphology of polypropylene surfaces of Ar plasma modification are characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometers and scanning electron microscope. The modified by plasma treatment of iPP (isotactic polypropylene) surface properties have been examined in a determination of free radicals. The modified active surfaces of polypropylene can induce grafting copolymerization of styrene onto polypropylene. The structure of grafting copolymer is characterized and the grafting percent of styrene onto polypropylene is calculated. The homopolymer of styrene can be formed under grafting copolymerization of styrene onto polypropylene, which follows that the alloying of polypropylene with styrene is achieved in situ.

  14. Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

    International Nuclear Information System (INIS)

    Stanishevsky, Andrei V.; Walock, Michael J.; Catledge, Shane A.

    2015-01-01

    Graphical abstract: - Highlights: • Single and binary gas plasma modification of nanodiamond powders studied. • Temperature-dependent effect of N 2 and N 2 /H 2 plasma reported for the first time. • Role of H 2 in H 2 /N 2 and H 2 /O 2 plasma modification of nanodiamond discussed. - Abstract: Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H 2 , N 2 , and O 2 gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H 2 in H 2 /N 2 and H 2 /O 2 binary gas plasmas on the DND structure and the temperature-dependent formation of various CNH x surface groups in N 2 and H 2 /N 2 plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O 2 plasma, whereas the N 2 plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N 2 plasma when the substrate temperature was above 1103 K.

  15. Surface modification of yttria stabilized zirconia by ion implantation

    International Nuclear Information System (INIS)

    Scholten, D.

    1987-01-01

    The results of investigations of surface modification by ion implantation in zirconia are described. As dopant material, iron was investigated thoroughly. The depth distribution of implanted ions depends on implantation parameters and the dopant-matrix system. The investigations of thermal stability of some implanted iron profiles by RBS and AES are described. Special interest lies in the thermal stability under working conditions of the zirconia material (400-1000 0 C). Radiation damage introduced in the implanted layer was investigated using transmission electron microscopy on polycrystalline material and channeling experiments on a single crystal implanted with iron. 179 refs.; 87 figs.; 20 tabs

  16. Enhancing the formation and shear resistance of nitrifying biofilms on membranes by surface modification

    DEFF Research Database (Denmark)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko

    2009-01-01

    Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG......) chains with two different functional groups (-PEG-NH2 and -PEG-CH3). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed...... structure might be possible explanations of the superiority of the -PEG-NH2 modification. The success of the-PEG-NH2 modification was independent of the original surface and might, therefore, be used in wastewater treatment bioreactors to improve reactor performance by making biofilm formation more stable...

  17. Morphological evolution of InP nano-dots and surface modifications after keV irradiation

    International Nuclear Information System (INIS)

    Paramanik, Dipak; Sahu, S N; Varma, Shikha

    2008-01-01

    Evolution and coarsening behaviour of self-assembled nano-dots fabricated on an InP surface by 3 keV Ar ion sputtering have been studied in conjunction with the structural modifications at the surface. The dots have been produced in off-normal geometry but in the absence of rotation. For small sputtering durations, the dots coarsen and agglomerate, up to a critical time t c , while the surface roughens and experiences a tensile stress. A relaxation in this stress is observed after the surface becomes amorphized at t c , beyond which an inverse coarsening, fragmentation of dots and a smoothened surface are observed

  18. Modification of preheated tungsten surface after irradiation at the GOL-3 facility

    Energy Technology Data Exchange (ETDEWEB)

    Shoshin, A.A., E-mail: shoshin@mail.ru [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Arakcheev, A.S.; Arzhannikov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Burdakov, A.V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, Novosibirsk 630092 (Russian Federation); Huber, A. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Ivanov, I.A. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Kuklin, K.N. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Polosatkin, S.V.; Postupaev, V.V.; Sinitsky, S.L. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Vasilyev, A.A. [Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2016-12-15

    Highlights: • Preheated tungsten was irradiated at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. • The crack pattern and the quantity of bubbles depend on the initial temperatures of the target. • The orientation of major crack networks correlates with the direction of machining of the samples. • Dust impact craters were found. - Abstract: The study is devoted to tungsten surface modification after irradiation at the GOL-3 facility with plasma loads corresponding to the ITER type I ELMs. In order to emulate heating with a steady plasma flux in the ITER divertor, some of the tungsten samples were preheated up to 500 °C. It was found out that the behavior of the surface modification (the crack pattern and the number of bubbles) depends on the initial temperature of the targets. While the orientation of major crack networks correlates with the direction of machining of the samples. Afterwards we have observed the process of craters’ formation caused by dust particle impacts.

  19. Modifications of the hydriding kinetics of a metallic surface, using ion implantation

    International Nuclear Information System (INIS)

    Crusset, D.

    1992-10-01

    Uranium reacts with hydrogen to form an hydride: this reaction leads to the total destruction of the material. To modify the reactivity of an uranium surface towards hydrogen, ion implantation was selected, among surface treatments techniques. Four elements (carbon, nitrogen, oxygen, sulfur) were implanted to different doses. The results show a modification of the hydriding mechanism and a significant increase in the reaction induction times, notably at high implantation doses. Several techniques (SIMS, X-rays phases analysis and residual stresses determination) were used to characterize the samples and understand the different mechanisms involved

  20. Preparation, Modification, and Application of Hollow Gold Nanospheres

    Directory of Open Access Journals (Sweden)

    Qiong-Qiong Ren

    2015-01-01

    Full Text Available Hollow gold nanospheres (HGNs have great potential applications in biological sensing, biomedical imaging, photothermal therapy, and drug delivery due to their unique localized surface plasmon resonance (LSPR feature, easy modification, good biocompatibility, and excellent photothermal conversion properties. In this review, the latest developments of HGNs in biosensing, bioimaging, photothermal therapy, and drug delivery are summarized, the synthesis methods, surface modification and bioconjugation of HGNs are also covered in this summary.

  1. Modeling polyvinyl chloride Plasma Modification by Neural Networks

    Science.gov (United States)

    Wang, Changquan

    2018-03-01

    Neural networks model were constructed to analyze the connection between dielectric barrier discharge parameters and surface properties of material. The experiment data were generated from polyvinyl chloride plasma modification by using uniform design. Discharge voltage, discharge gas gap and treatment time were as neural network input layer parameters. The measured values of contact angle were as the output layer parameters. A nonlinear mathematical model of the surface modification for polyvinyl chloride was developed based upon the neural networks. The optimum model parameters were obtained by the simulation evaluation and error analysis. The results of the optimal model show that the predicted value is very close to the actual test value. The prediction model obtained here are useful for discharge plasma surface modification analysis.

  2. Laser surface modification of electrically conductive fabrics: Material performance improvement and design effects

    Science.gov (United States)

    Tunakova, Veronika; Hrubosova, Zuzana; Tunak, Maros; Kasparova, Marie; Mullerova, Jana

    2018-01-01

    Development of lightweight flexible materials for electromagnetic interference shielding has obtained increased attention in recent years particularly for clothing, textiles in-house use and technical applications especially in areas of aircraft, aerospace, automobiles and flexible electronics such as portable electronics and wearable devices. There are many references in the literature concerning development and investigation of electromagnetic shielding lightweight flexible materials especially textile based with different electrically conductive additives. However, only little attention is paid to designing and enhancing the properties of these special fabrics by textile finishing processes. Laser technology applied as a physical treatment method is becoming very popular and can be used in different applications to make improvement and even overcome drawbacks of some of the traditional processes. The main purpose of this study is firstly to analyze the possibilities of transferring design onto the surface of electrically conductive fabrics by laser beam and secondly to study of effect of surface modification degree on performance of conductive fabric including electromagnetic shielding ability and mechanical properties. Woven fabric made of yarns containing 10% of extremely thin stainless steel fiber was used as a conductive substrate.

  3. Porous silicon photoluminescence modification by colloidal gold nanoparticles: Plasmonic, surface and porosity roles

    International Nuclear Information System (INIS)

    Mora, M.B. de la; Bornacelli, J.; Nava, R.; Zanella, R.; Reyes-Esqueda, J.A.

    2014-01-01

    Metal nanoparticles on semiconductors are of interest because of the tunable effect of the surface plasmon resonance on the physical properties of the semiconductor. In this work, colloidal gold nanoparticles obtained by two different methods, with an average size of 6.1±2.0 nm and 5.0±2.0 nm, were added to luminescent porous silicon by drop casting. The gold nanoparticles interact with porous silicon by modifying its optical properties such as photoluminescence. That being said, plasmon effects are not the only to be taken into account; as shown in this work, surface chemical modification and porosity also play a key role in the final performance of photoluminescence of a porous silicon–gold nanoparticle hybrid system. -- Highlights: • A hybrid material consisting of porous silicon and gold nanoparticles was fabricated. • Porous silicon/gold nanoparticle hybrid material was made by drop casting. • Influence of plasmonics, surface chemical modification and porosity on the optical behavior of our material was analyzed. • Porosity is proposed as a parameter control to obtain the best effects on luminescence of the hybrid plasmonic material

  4. Porous silicon photoluminescence modification by colloidal gold nanoparticles: Plasmonic, surface and porosity roles

    Energy Technology Data Exchange (ETDEWEB)

    Mora, M.B. de la; Bornacelli, J. [Instituto de Física, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico); Nava, R. [Centro de Investigación en Energía, Universidad Nacional Autónoma de México, Temixco, Morelos 62580 (Mexico); Zanella, R. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico); Reyes-Esqueda, J.A., E-mail: betarina@gmail.com [Instituto de Física, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico)

    2014-02-15

    Metal nanoparticles on semiconductors are of interest because of the tunable effect of the surface plasmon resonance on the physical properties of the semiconductor. In this work, colloidal gold nanoparticles obtained by two different methods, with an average size of 6.1±2.0 nm and 5.0±2.0 nm, were added to luminescent porous silicon by drop casting. The gold nanoparticles interact with porous silicon by modifying its optical properties such as photoluminescence. That being said, plasmon effects are not the only to be taken into account; as shown in this work, surface chemical modification and porosity also play a key role in the final performance of photoluminescence of a porous silicon–gold nanoparticle hybrid system. -- Highlights: • A hybrid material consisting of porous silicon and gold nanoparticles was fabricated. • Porous silicon/gold nanoparticle hybrid material was made by drop casting. • Influence of plasmonics, surface chemical modification and porosity on the optical behavior of our material was analyzed. • Porosity is proposed as a parameter control to obtain the best effects on luminescence of the hybrid plasmonic material.

  5. PREFACE Surface Modifications of Diamond and Related Materials (Session D, E-MRS Spring Meeting)

    Science.gov (United States)

    Nebel, Christoph E.

    2010-11-01

    This special issue contains selected papers which were presented at the E-MRS Symposium BIOMATERIALS, SENSORS & SURFACES, D: 'Surface modifications of diamond and related materials' which was held on 7-9 June 2010 in Strasbourg (France). With about 54 oral and poster presentations given from teams all over the world it was a very interesting, dense and lively meeting. The symposium focused on chemical modifications applied to graft surfaces of diamond, nano-diamond particles, diamond-like carbon, graphene, graphite and carbon nano-tubes with linker molecular layers for realization of bio-sensors, bio-markers, separation techniques, and switchable chemical links. Presented techniques span spontaneous bonding to photo-chemical attachment, electrochemical modifications, to Suzuki-coupling of aryl molecules. Special attention was drawn to mechanisms driving bonding kinetics such as electron transfer reactions, hydrogen cleavage reactions by nucleophilic molecules and growths schemas which vary from correlated two-dimensional chain reactions to three-dimensional cross polymerization. Hydrogen terminations, surface defects, surface roughness and atomic arrangements of surface carbon atoms were of interest to elucidate bonding mechanisms. In addition, bonding stability, either of linker molecules or of complex functionalized surfaces with DNA, proteins and enzymes was discussed by several speakers as well as details of the electronic interfaces between solid transducers and bio-layers. Here the characterization of surface and interface defect densities, of Fermi level pinning and of electron transfer rates was a major topic. Miniaturization of sensor area and application of new detection schemas was discussed. Diamond nano-particles which are increasingly used as biomarkers in drug delivery experiments also attracted attention. The organizers express our gratitude to the international members of the scientific committee who actively contributed to ensure an attractive

  6. Surface Modification of Micro-Alloyed High-Strength Low-Alloy Steel by Controlled TIG Arcing Process

    Science.gov (United States)

    Ghosh, P. K.; Kumar, Ravindra

    2015-02-01

    Surface modification of micro-alloyed HSLA steel plate has been carried out by autogenous conventional and pulse current tungsten inert gas arcing (TIGA) processes at different welding parameters while the energy input was kept constant. At a given energy input the influence of pulse parameters on the characteristics of surface modification has been studied in case of employing single and multi-run procedure. The role of pulse parameters has been studied by considering their summarized influence defined by a factor Φ. The variation in Φ and pulse frequency has been found to significantly affect the thermal behavior of fusion and accordingly the width and penetration of the modified region along with its microstructure, hardness and wear characteristics. It is found that pulsed TIGA is relatively more advantageous over the conventional TIGA process, as it leads to higher hardness, improved wear resistance, and a better control over surface characteristics.

  7. Surface monofunctionalized polymethyl pentene hollow fiber membranes by plasma treatment and hemocompatibility modification for membrane oxygenators

    Science.gov (United States)

    Huang, Xin; Wang, Weiping; Zheng, Zhi; Fan, Wenling; Mao, Chun; Shi, Jialiang; Li, Lei

    2016-01-01

    The hemocompatibility of polymethyl pentene (PMP) hollow fiber membranes (HFMs) was improved through surface modification for membrane oxygenator applications. The modification was performed stepwise with the following: (1) oxygen plasma treatment, (2) functionalization of monosort hydroxyl groups through NaBH4 reduction, and (3) grafting 2-methacryloyloxyethyl phosphorylcholine (MPC) or heparin. SEM, ATR-FTIR, and XPS analyses were conducted to confirm successful grafting during the modification. The hemocompatibility of PMP HFMs was analyzed and compared through protein adsorption, platelet adhesion, and coagulation tests. Pure CO2 and O2 permeation rates, as well as in vitro gas exchange rates, were determined to evaluate the mass transfer properties of PMP HFMs. SEM results showed that different nanofibril topographies were introduced on the HFM surface. ATR-FTIR and XPS spectra indicated the presence of functionalization of monosort hydroxyl group and the grafting of MPC and heparin. Hemocompatibility evaluation results showed that the modified PMP HFMs presented optimal hemocompatibility compared with pristine HFMs. Gas permeation results revealed that gas permeation flux increased in the modified HFMs because of dense surface etching during the plasma treatment. The results of in vitro gas exchange rates showed that all modified PMP HFMs presented decreased gas exchange rates because of potential surface fluid wetting. The proposed strategy exhibits a potential for fabricating membrane oxygenators for biomedical applications to prevent coagulation formation and alter plasma-induced surface topology and composition.

  8. Nanosecond laser surface modification of AISI 304L stainless steel: Influence the beam overlap on pitting corrosion resistance

    International Nuclear Information System (INIS)

    Pacquentin, Wilfried; Caron, Nadège; Oltra, Roland

    2014-01-01

    Surface modifications of AISI 304L stainless steel by laser surface melting (LSM) were investigated using a nanosecond pulsed laser-fibre doped by ytterbium at different overlaps. The objective was to study the change in the corrosion properties induced by the treatment of the outer-surface of the stainless steel without modification of the bulk material. Different analytical techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES) were used to characterize the laser-melted surface. The corrosion resistance was evaluated in a chloride solution at room temperature by electrochemical tests. The results showed that the crystallographic structure, the chemical composition, the properties of the induced oxide layer and consequently the pitting corrosion resistance strongly depend on the overlap rate. The most efficient laser parameters led to an increase of the pitting potential by more than 300 mV, corresponding to a quite important improvement of the corrosion resistance. This latter was correlated to chromium enrichment (47 wt.%) at the surface of the stainless steel and the induced absence of martensite and ferrite phases. However, these structural and chemical modifications were not sufficient to explain the change in corrosion behaviour: defects and adhesion of the surface oxide layer must have been taken into consideration.

  9. Enhancing adhesion of yeast brewery strains to chamotte carriers through aminosilane surface modification.

    Science.gov (United States)

    Berlowska, Joanna; Kregiel, Dorota; Ambroziak, Wojciech

    2013-07-01

    The adhesion of cells to solid supports is described as surface-dependent, being largely determined by the properties of the surface. In this study, ceramic surfaces modified using different organosilanes were tested for proadhesive properties using industrial brewery yeast strains in different physiological states. Eight brewing strains were tested: bottom-fermenting Saccharomyces pastorianus and top-fermenting Saccharomyces cerevisiae. To determine adhesion efficiency light microscopy, scanning electron microscopy and the fluorymetric method were used. Modification of chamotte carriers by 3-(3-anino-2-hydroxy-1-propoxy) propyldimethoxysilane and 3-(N, N-dimethyl-N-2-hydroxyethyl) ammonium propyldimethoxysilane groups increased their biomass load significantly.

  10. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-11-03

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  11. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-01-01

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  12. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    Directory of Open Access Journals (Sweden)

    Himansu Sekhar Nanda

    2016-11-01

    Full Text Available The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium-doped cerium oxide nanoparticles (SmCNPs as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy-ethoxy]-ethoxy}-hexyl triethoxysilane (MEEETES were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  13. The increase of apatite layer formation by the poly(3-hydroxybutyrate) surface modification of hydroxyapatite and β-tricalcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Szubert, M., E-mail: mm.szubert@gmail.com [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Adamska, K. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Szybowicz, M. [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland); Jesionowski, T. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland); Buchwald, T. [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland); Voelkel, A. [Faculty of Chemical Technology, Poznan University of Technology, Poznan (Poland)

    2014-01-01

    The aim of this study was the surface modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) grafting and characterization of modificates. The bioactivity examination was carried out by the determination to grow an apatite layer on modified materials during incubation in simulated body fluid at 37 °C. The additional issue taken up in this paper was to investigate the influence of fluid replacement. The process of the surface modification of biomaterials was evaluated by means of infrared and Raman spectroscopy. Formation of the apatite layer was assessed by means of scanning electron microscopy and confirmed by energy dispersive, Raman and Fourier transformed infrared spectroscopy. During exposure in simulated body fluid, the variation of the zeta potential, pH measurement and relative weight was monitored. Examination of scanning electron microscopy micrographs suggests that modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) significantly increases apatite layer formation. Raman spectroscopy evaluation revealed that the formation of the apatite layer was more significant in the case of hydroxyapatite modificate, when compared to the β-tricalcium phosphate modificate. Both modificates were characterized by stable pH, close to the natural pH of human body fluids. Furthermore, we have shown that a weekly changed, simulated body fluid solution increases apatite layer formation. - Highlights: • Surface modification of HA and β-TCP was performed by PHB grafting. • The growth of apatite layer on materials was examined in simulated body fluid (SBF). • The bioactivity of obtained materials was proved. • The replacement of SBF solution plays an important role in the process of apatite formation.

  14. The increase of apatite layer formation by the poly(3-hydroxybutyrate) surface modification of hydroxyapatite and β-tricalcium phosphate

    International Nuclear Information System (INIS)

    Szubert, M.; Adamska, K.; Szybowicz, M.; Jesionowski, T.; Buchwald, T.; Voelkel, A.

    2014-01-01

    The aim of this study was the surface modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) grafting and characterization of modificates. The bioactivity examination was carried out by the determination to grow an apatite layer on modified materials during incubation in simulated body fluid at 37 °C. The additional issue taken up in this paper was to investigate the influence of fluid replacement. The process of the surface modification of biomaterials was evaluated by means of infrared and Raman spectroscopy. Formation of the apatite layer was assessed by means of scanning electron microscopy and confirmed by energy dispersive, Raman and Fourier transformed infrared spectroscopy. During exposure in simulated body fluid, the variation of the zeta potential, pH measurement and relative weight was monitored. Examination of scanning electron microscopy micrographs suggests that modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) significantly increases apatite layer formation. Raman spectroscopy evaluation revealed that the formation of the apatite layer was more significant in the case of hydroxyapatite modificate, when compared to the β-tricalcium phosphate modificate. Both modificates were characterized by stable pH, close to the natural pH of human body fluids. Furthermore, we have shown that a weekly changed, simulated body fluid solution increases apatite layer formation. - Highlights: • Surface modification of HA and β-TCP was performed by PHB grafting. • The growth of apatite layer on materials was examined in simulated body fluid (SBF). • The bioactivity of obtained materials was proved. • The replacement of SBF solution plays an important role in the process of apatite formation

  15. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Miksovsky, J. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Voss, A. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Kozarova, R. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Kocourek, T.; Pisarik, P. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Ceccone, G. [Unit Nanobiosciences, European Commission Joint Research Centre, Ispra (Italy); Kulisch, W. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Jelinek, M. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Apostolova, M.D. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Reithmaier, J.P. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Popov, C., E-mail: popov@ina.uni-kassel.de [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany)

    2014-04-01

    Graphical abstract: - Highlights: • UNCD and DLC films were modified by UV/O{sub 3} treatments, O{sub 2} or NH{sub 3}-containing plasmas. • Surface composition, wettability and surface energy change upon modifications. • Higher efficiency of UNCD modifications was observed. • Cell attachment and growth were influenced by the surface termination and roughness. - Abstract: Diamond and diamond-like carbon (DLC) films possess a set of excellent physical and chemical properties which together with a high biocompatibility make them attractive candidates for a number of medical and biotechnological applications. In the current work thin ultrananocrystalline diamond (UNCD) and DLC films were comparatively investigated with respect to cell attachment and proliferation after different surface modifications. The UNCD films were prepared by microwave plasma enhanced chemical vapor deposition, the DLC films by pulsed laser deposition (PLD). The films were comprehensively characterized with respect to their basic properties, e.g. crystallinity, morphology, chemical bonding nature, etc. Afterwards the UNCD and DLC films were modified applying O{sub 2} or NH{sub 3}/N{sub 2} plasmas and UV/O{sub 3} treatments to alter their surface termination. The surface composition of as-grown and modified samples was studied by X-ray photoelectron spectroscopy (XPS). Furthermore the films were characterized by contact angle measurements with water, formamide, 1-decanol and diiodomethane; from the results obtained the surface energy with its dispersive and polar components was calculated. The adhesion and proliferation of MG63 osteosarcoma cells on the different UNCD and DLC samples were assessed by measurement of the cell attachment efficiency and MTT assays. The determined cell densities were compared and correlated with the surface properties of as-deposited and modified UNCD and DLC films.

  16. Surface Modifications of Support Partitions for Stabilizing Biomimetic Membrane Arrays

    DEFF Research Database (Denmark)

    Perry, Mark; Hansen, Jesper Schmidt; Jensen, Karin Bagger Stibius

    2011-01-01

    with a high signal-to-noise (s/n) ratio. We demonstratesd this by reconstituting gA and α-hemolysin (α-HL) into BLM arrays. The improvement in membrane array lifetime and s/n ratio demonstrates that surface plasma polymerization of the supporting partition can be used to increase the stability of biomimetic......Black lipid membrane (BLM) formation across apertures in an ethylene tetra-fluoroethylene (ETFE) partition separating two aqueous compartments is an established technique for the creation of biomimetic membranes. Recently multi-aperture BLM arrays have attracted interest and in order to increase...... BLM array stability we studied the effect of covalently modifying the partition substrate using surface plasma polymerization with hydrophobic n-hexene, 1-decene and hexamethyldisiloxane (HMDSO) as modification groups. Average lifetimes across singlesided HMDSO modified partitions or using 1-decene...

  17. Surface modification of Ti-30Ta alloy by electrospun PCL deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wada, C.M.; Rangel, A.L.R.; Souza, M.A. de; Claro, A.P.R.A.; Rezende, M.C.R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil); Almeida, R. dos S. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2014-07-01

    Full text: Surface modifications techniques have been used for change the inert surface of the titanium alloys for better interaction. Ingots of the experimental alloy Ti30Ta were melted in an arc furnace and re-melted ten times at least. They were homogenized under vacuum at 1000 °C for 86. 4 ks to eliminate chemical segregation and cold-worked by swaging. Discs were immersed in aqueous NaOH solution for 24 h, dried at room temperature, immersed in HCl and dried at 40 °C in oven for 24 hours. Followed, PCL fibers were deposited on the Ti30Ta alloy discs surfaces by electrospinning. Plasma treatment was carried out for change PCL electrospun by using stainless steel plasma reactor. Samples were immersed in SBF 5x solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and SBF immersion. Results are very interesting for biomedical applications. (author)

  18. Surface modification of Ti-30Ta alloy by electrospun PCL deposition

    International Nuclear Information System (INIS)

    Wada, C.M.; Rangel, A.L.R.; Souza, M.A. de; Claro, A.P.R.A.; Rezende, M.C.R.; Almeida, R. dos S.

    2014-01-01

    Full text: Surface modifications techniques have been used for change the inert surface of the titanium alloys for better interaction. Ingots of the experimental alloy Ti30Ta were melted in an arc furnace and re-melted ten times at least. They were homogenized under vacuum at 1000 °C for 86. 4 ks to eliminate chemical segregation and cold-worked by swaging. Discs were immersed in aqueous NaOH solution for 24 h, dried at room temperature, immersed in HCl and dried at 40 °C in oven for 24 hours. Followed, PCL fibers were deposited on the Ti30Ta alloy discs surfaces by electrospinning. Plasma treatment was carried out for change PCL electrospun by using stainless steel plasma reactor. Samples were immersed in SBF 5x solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and SBF immersion. Results are very interesting for biomedical applications. (author)

  19. Plasma transferred arc surface modification of atmospheric plasma sprayed ceramic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ulutan, Mustafa; Kilicay, Koray; Kaya, Esad; Bayar, Ismail [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

    2016-08-15

    In this study, a 90MnCrV8 steel surface was coated with aluminum oxide and chromium oxide powders through the Atmospheric plasma spray (APS) and Plasma transferred arc (PTA) methods. The effects of PTA surface melting on the microstructure, hardness, and wear behavior were investigated. The microstructures of plasma-sprayed and modified layers were characterized by Optical microscopy (OM), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS). The dry-sliding wear properties of the samples were determined through the ball-on-disk wear test method. Voids, cracks, and nonhomogeneous regions were observed in the microstructure of the APS ceramic-coated surface. These microstructure defects were eliminated by the PTA welding process. The microhardness of the samples was increased. Significant reductions in wear rate were observed after the PTA surface modification. The wear resistance of ceramic coatings increased 7 to 12 times compared to that of the substrate material.

  20. Laser-induced surface modification of biopolymers – micro/nanostructuring and functionalization

    Science.gov (United States)

    Stankova, N. E.; Atanasov, P. A.; Nedyalkov, N. N.; Tatchev, Dr; Kolev, K. N.; Valova, E. I.; Armyanov, St. A.; Grochowska, K.; Śliwiński, G.; Fukata, N.; Hirsch, D.; Rauschenbach, B.

    2018-03-01

    The medical-grade polydimethylsiloxane (PDMS) elastomer is a widely used biomaterial in medicine for preparation of high-tech devices because of its remarkable properties. In this paper, we present experimental results on surface modification of PDMS elastomer by using ultraviolet, visible, and near-infrared ns-laser system and investigation of the chemical composition and the morphological structure inside the treated area in dependence on the processing parameters – wavelength, laser fluence and number of pulses. Remarkable chemical transformations and changes of the morphological structure were observed, resulting in the formation of a highly catalytically active surface, which was successfully functionalized via electroless Ni and Pt deposition by a sensitizing-activation free process. The results obtained are very promising in view of applying the methods of laser-induced micro- and nano-structuring and activation of biopolymers’ surface and further electroless metal plating to the preparation of, e.g., multielectrode arrays (MEAs) devices in neural and muscular surface interfacing implantable systems.

  1. On the Electrodeposition of Ca-P Coatings on Nitinol Alloy: A Comparison Between Different Surface Modification Methods

    Science.gov (United States)

    Etminanfar, M. R.; Khalil-Allafi, J.

    2016-02-01

    In this study, a combination of surface modification process and the electrochemical deposition of Ca-P coatings was used for the modification of the Nitinol shape memory alloy. DSC, SEM, GIB-XRD, FT-Raman, XPS, and FTIR measurements were performed for the characterization of the samples. Results indicated that chemical etching and boiling of the samples in distilled water formed TiO film on the surface. After the chemical modification, subsequent aging of the sample, at 470 °C for 30 min, converted the oxide film to a stable structure of titanium dioxide. In that case, the treated substrate indicated a superelastic behavior. At the same electrochemical condition, the treated substrate revealed more stable and uniform Ca-P coatings in comparison with the abraded Nitinol substrate. This difference was attributed to the presence of hydroxyl groups on the titanium dioxide surface. Also, after soaking the sample in SBF, the needle-like coating on the treated substrate was completely covered with the hydroxyapatite phase which shows a good bioactivity of the coating.

  2. Surface modification and stability of detonation nanodiamonds in microwave gas discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Stanishevsky, Andrei V., E-mail: astan@uab.edu; Walock, Michael J.; Catledge, Shane A.

    2015-12-01

    Graphical abstract: - Highlights: • Single and binary gas plasma modification of nanodiamond powders studied. • Temperature-dependent effect of N{sub 2} and N{sub 2}/H{sub 2} plasma reported for the first time. • Role of H{sub 2} in H{sub 2}/N{sub 2} and H{sub 2}/O{sub 2} plasma modification of nanodiamond discussed. - Abstract: Detonation nanodiamonds (DND), with low hydrogen content, were exposed to microwave plasma generated in pure H{sub 2}, N{sub 2}, and O{sub 2} gases and their mixtures, and investigated using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. Considerable alteration of the DND surface was observed under the plasma conditions for all used gases, but the diamond structure of the DND particle core was preserved in most cases. The stabilizing effect of H{sub 2} in H{sub 2}/N{sub 2} and H{sub 2}/O{sub 2} binary gas plasmas on the DND structure and the temperature-dependent formation of various CNH{sub x} surface groups in N{sub 2} and H{sub 2}/N{sub 2} plasmas were observed and discussed for the first time. DND surface oxidation and etching were the main effects of O{sub 2} plasma, whereas the N{sub 2} plasma led to DND surfaces rich in amide groups below 1073 K and nitrile groups at higher temperatures. Noticeable graphitization of the DND core structure was detected only in N{sub 2} plasma when the substrate temperature was above 1103 K.

  3. Surface modification of RuO2 electrodes by laser irradiation and ion ...

    Indian Academy of Sciences (India)

    RuO2 thin layers were deposited on Ti supports by thermal decomposition of RuCl3 at 400°C. Some of the samples were subjected to laser irradiation between 0.5 and 1.5 J cm-2. Some others to Kr bombardment with doses between 1015 and 1016 cm-2. Modifications introduced by the surface treatments were monitored ...

  4. Surface modification and functionalization of carbon nanotube with some organic compounds

    International Nuclear Information System (INIS)

    Le, Van Thu; Ngo, Cao Long; Le, Quoc Trung; Ngo, Trinh Tung; Nguyen, Duc Nghia; Vu, Minh Thanh

    2013-01-01

    In this work the surface modification and functionalization of carbon nanotubes (CNTs) were investigated. CNTs were firstly treated by acid mixture H 2 SO 4 /HNO 3 to introduce the carboxylic group onto the surface of CNTs. This carboxylic group was used as reaction precursor in the functionalization. Two functional groups, dodecylamine (DDA) and 3-aminopropyl triethoxysilane (3-APTES), were successfully covalently attached to CNTs. The functionalized CNTs were characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, differential scanning calorimetry and thermal gravimetric analysis (DSC/TGA) and transmission electron microscopy (TEM) methods. The CNTs attached to the organofunctional moieties have greater versatility for further utilization in different application fields such as biology, nanocomposites, solar energy, etc. (paper)

  5. Surface modification by EUV laser beam based on capillary discharge

    Czech Academy of Sciences Publication Activity Database

    Frolov, Oleksandr; Koláček, Karel; Schmidt, Jiří; Štraus, Jaroslav; Prukner, Václav; Shukurov, A.

    -, č. 58 (2011), s. 484-487 ISSN 2010-376X. [International Conference on Fusion and Plasma Physics. Bali, Indonésie, 26.10.2011-28.10.2011] R&D Projects: GA AV ČR KAN300100702; GA MŠk LA08024; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508 Keywords : soft x-ray * EUV * laser * radiation * source * capillary * discharge * plasma * ablation * surface modification Subject RIV: BL - Plasma and Gas Discharge Physics http://www.waset.org/journals/waset/v58/v58-99.pdf

  6. Surface modification of additive manufactured metal products by an intense electron beam

    Science.gov (United States)

    Teresov, A. D.; Koval, N. N.; Ivanov, Yu F.; Petrikova, E. A.; Krysina, O. V.

    2017-11-01

    On the example of VT6 titanium alloy it is shown that successive surface modification of additive manufactured metal specimens in vacuum at an argon pressure of 3.5·10-2 by ten pulses with 200 μs, 45 J/cm2 and then by three pulses with 50 μm, 20 J/cm2 provides a considerable decrease in their porosity and surface roughness (20 times for Ra) while their surface microhardness, friction coefficient, and wear level remain almost unchanged. After electron beam irradiation, the ultimate tensile strength of the material increases 1.33 times, and its tensile strain 1.18 times. For specimens obtained by conventional metallurgy and irradiated in the same modes, no such effects are observed.

  7. Polytetrafluoroethylene surface modification by filamentary and homogeneous dielectric barrier discharges in air

    International Nuclear Information System (INIS)

    Fang Zhi; Hao Lili; Yang Hao; Xie Xiangqian; Qiu Yuchang; Edmund, Kuffel

    2009-01-01

    In this paper, polytetrafluoroethylene (PTFE) films are modified using non-equilibrium plasma generated by homogeneous DBD in air at medium pressure, and the results are compared to those treated by using filamentary DBD in air at atmospheric pressure. The surface properties of PTFE films before and after the treatments are studied using contact angle and surface energy measurement, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the plasma treatments modify the PTFE surface in both morphology and composition. The PTFE films modified in both treatments show a remarkable decrease in water contact and a remarkable increase in surface energy. XPS analysis reveals that oxygen-containing polar groups are introduced onto the PTFE surface, and SEM analysis shows that the surfaces of the films are etched after both the treatments. It is found that homogeneous DBD is more effective in PTFE surface modification than filamentary DBD as it can make the contact angle decline to a lower level by introducing more oxygen-containing groups, and the possible reason for this effect is discussed.

  8. Surface modification by electrolytic plasma processing for high Nb-TiAl alloys

    Science.gov (United States)

    Gui, Wanyuan; Hao, Guojian; Liang, Yongfeng; Li, Feng; Liu, Xiao; Lin, Junpin

    2016-12-01

    Metal surface modification by electrolytic plasma processing (EPP) is an innovative treatment widely commonly applied to material processing and pretreatment process of coating and galvanization. EPP involves complex processes and a great deal of parameters, such as preset voltage, current, solution temperature and processing time. Several characterization methods are presented in this paper for evaluating the micro-structure surfaces of Ti45Al8Nb alloys: SEM, EDS, XRD and 3D topography. The results showed that the oxide scale and other contaminants on the surface of Ti45Al8Nb alloys can be effectively removed via EPP. The typical micro-crater structure of the surface of Ti45Al8Nb alloys were observed by 3D topography after EPP to find that the mean diameter of the surface structure and roughness value can be effectively controlled by altering the processing parameters. The mechanical properties of the surface according to nanomechanical probe testing exhibited slight decrease in microhardness and elastic modulus after EPP, but a dramatic increase in surface roughness, which is beneficial for further processing or coating.

  9. Response of Elk to Habitat Modification Near Natural Gas Development

    Science.gov (United States)

    Van Dyke, Fred; Fox, Autumn; Harju, Seth M.; Dzialak, Matthew R.; Hayden-Wing, Larry D.; Winstead, Jeffrey B.

    2012-11-01

    Elk (Cervus elaphus) are known to shift habitat use in response to environmental modifications, including those associated with various forms of energy development. The specific behavioral responses underlying these trends, however, have not been effectively studied. To investigate such effects, we examined elk response to habitat alteration near natural gas wells in Las Animas County, Colorado, USA in 2008-2010. We created 10 1-ha openings in forests adjacent to 10 operating natural gas wells by removing standing timber in 2008, with concomitant establishment of 10 1-ha control sites adjacent to the same wells. On each site, we estimated elk use, indexed by pellet density, before and after timber removal. Concurrently, we measured plant production and cover, nutritional quality, species composition and biomass removed by elk and other large herbivores. Species richness and diversity, graminoid and forb cover, and graminoid and forb biomass increased on cut sites following tree removal. Differences were greater in 2010 than in 2009, and elk and deer removed more plant biomass in 2010 than 2009. Elk use of cut sites was 37 % lower than control sites in 2009, but 46 % higher in 2010. The initially lower use of cut sites may be attributable to lack of winter forage on these sites caused by timber removal and associated surface modification. The increased use of cut sites in 2010 suggested that elk possessed the behavioral capacity, over time, to exploit enhanced forage resources in the proximity of habitat modifications and human activity associated with maintenance of operating natural gas wells.

  10. Surface modification of titanium hydride with epoxy resin via microwave-assisted ball milling

    International Nuclear Information System (INIS)

    Ning, Rong; Chen, Ding; Zhang, Qianxia; Bian, Zhibing; Dai, Haixiong; Zhang, Chi

    2014-01-01

    Highlights: • TiH 2 was modified with epoxy resin by microwave-assisted ball milling. • The epoxy ring was opened under the coupling effect of microwave and ball milling. • Microwave-assisted ball milling improved the compatibility of TiH 2 with epoxy. - Abstract: Surface modification of titanium hydride with epoxy resin was carried out via microwave-assisted ball milling and the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR). A sedimentation test was performed to investigate the compatibility of the modified nano titanium hydride with the epoxy resin. The results show that the epoxy resin molecules were grafted on the surface of nano titanium hydride particles during the microwave-assisted ball milling process, which led to the improvement of compatibility between the nanoparticles and epoxy resin. According to the FT-IR, the grafting site was likely to be located around the epoxy group due to the fact that the epoxy ring was opened. However, compared with microwave-assisted ball milling, the conventional ball milling could not realize the surface modification, indicating that the coupling effect of mechanical force and microwave played a key role during the process

  11. Surface modification of blood-contacting biomaterials by plasma-polymerized superhydrophobic films using hexamethyldisiloxane and tetrafluoromethane as precursors

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Chaio-Ru [Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen District, Taichung City 40724, Taiwan (China); Lin, Cheng-Wei [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, No. 666, Buzih Rd., Beitun District, Taichung City 40601, Taiwan (China); Chou, Chia-Man, E-mail: cmchou@vghtc.gov.tw [Department of Surgery, Taichung Veterans General Hospital, No. 1650, Sec. 4, Taiwan Boulevard, Seatwen District, Taichung City 40705, Taiwan (China); Department of Medicine, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Beitou District, Taipei City 11221, Taiwan (China); Chung, Chi-Jen, E-mail: cjchung@seed.net.tw [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, No. 666, Buzih Rd., Beitun District, Taichung City 40601, Taiwan (China); He, Ju-Liang [Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen District, Taichung City 40724, Taiwan (China)

    2015-08-15

    Highlights: • Biomaterials modified by nanoparticle-containing plasma polymerized films. • A superhydrophoic film was obtained, and the properties of the coating were examined. • In vitro blood compatibility tests revealed neither platelet adhesion nor fibrinogen adsorption. • Surface modification technology of medical devices: non-cytotoxic and no blood clot formation. - Abstract: This paper proposes a plasma polymerization system that can be used to modify the surface of the widely used biomaterial, polyurethane (PU), by employing low-cost hexamethyldisiloxane (HMDSO) and tetrafluoromethane (CF{sub 4}) as precursors; this system features a pulsed-dc power supply. Plasma-polymerized HMDSO/CF{sub 4} (pp-HC) with coexisting micro- and nanoscale morphology was obtained as a superhydrophobic coating material by controlling the HMDSO/CF{sub 4} (f{sub H}) monomer flow ratio. The developed surface modification technology can be applied to medical devices, because it is non-cytotoxic and has favorable hemocompatibility, and no blood clots form when the device surface direct contacts. Experimental results reveal that the obtained pp-HC films contained SiO{sub x} nanoparticles randomly dispersed on the micron-scale three-dimensional network film surface. The −CF functional group, −CF{sub 2} bonding, and SiO{sub x} were detected on the film surface. The maximal water contact angle of the pp-HC coating was 161.2°, apparently attributable to the synergistic effect of the coexisting micro- and nanoscale surface morphology featuring a low surface-energy layer. The superhydrophobic and antifouling characteristics of the coating were retained even after it was rubbed 20 times with a steel wool tester. Results of in vitro cytotoxicity, fibrinogen adsorption, and platelet adhesion tests revealed favorable myoblast cell proliferation and the virtual absence of fibrinogen adsorption and platelet adhesion on the pp-HC coated specimens. These quantitative findings imply

  12. Surface modification of cellulose isolated from Sesamun indicum underutilized seed: A means of enhancing cellulose hydrophobicity

    Directory of Open Access Journals (Sweden)

    Adewale Adewuyi

    2017-09-01

    Full Text Available Cellulose (SC isolated from sesame seed (SS was surface modified with the introduction of an ester functional group via a simple reaction to produce the modified product (SA. SS, SC and SA were characterized using Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TG, particle size distribution (PSD, zeta potential and scanning electron microscopy (SEM. SC and SA were evaluated for their water holding capacity (WC, oil holding capacity (OC, swelling capacity (SW and their ability to adsorb heavy metals. The FTIR revealed peaks corresponding to the formation of the ester functional group at the surface of SA. The crystallinity of SC was 28.02% but after the modification, it increased to 77.03% in SA. The PSD of SC and SA was both monomodal with sizes of 10.1305 μm in SC and 10.2511 μm in SA. The adsorption capacity of SC towards Pb (II and Cu (II ions was higher than that of SA. However, SA was unable to adsorb Cu (II ions. SA exhibited the lower WC and SW values as compared to SC which suggested an improved hydrophobicity after the modification. This study has shown that hydrophobicity can be improved in cellulose via surface modification.

  13. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.F. [Xi' an High-technology Institute, Xi' an 710025 (China)], E-mail: xiaofang_liu@263.net; Wu, Q.Y.; Wang, H.G. [Xi' an High-technology Institute, Xi' an 710025 (China)

    2008-06-15

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion.

  14. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    International Nuclear Information System (INIS)

    Liu, X.F.; Wu, Q.Y.; Wang, H.G.

    2008-01-01

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion

  15. Surface modification of montmorillonite on surface Acid-base characteristics of clay and thermal stability of epoxy/clay nanocomposites.

    Science.gov (United States)

    Park, Soo-Jin; Seo, Dong-Il; Lee, Jae-Rock

    2002-07-01

    In this work, the effect of surface treatments on smectitic clay was investigated in surface energetics and thermal behaviors of epoxy/clay nanocomposites. The pH values, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the effect of cation exchange on clay surface and the exfoliation phenomenon of clay interlayer. The surface energetics of clay and thermal properties of epoxy/clay nanocomposites were investigated in contact angles and thermogravimetric analysis (TGA), respectively. From the experimental results, the surface modification of clay by dodecylammonium chloride led to the increases in both distance between silicate layers of about 8 A and surface acid values, as well as in the electron acceptor component (gamma(+)(s)) of surface free energy, resulting in improved interfacial adhesion between basic (or electron donor) epoxy resins and acidic (electron acceptor) clay interlayers. Also, the thermal stability of nanocomposites was highly superior to pure epoxy resin due to the presence of the well-dispersed clay nanolayer, which has a barrier property in a composite system.

  16. Laser surface modification of decellularized extracellular cartilage matrix for cartilage tissue engineering.

    Science.gov (United States)

    Goldberg-Bockhorn, Eva; Schwarz, Silke; Subedi, Rachana; Elsässer, Alexander; Riepl, Ricarda; Walther, Paul; Körber, Ludwig; Breiter, Roman; Stock, Karl; Rotter, Nicole

    2018-02-01

    The implantation of autologous cartilage as the gold standard operative procedure for the reconstruction of cartilage defects in the head and neck region unfortunately implicates a variety of negative effects at the donor site. Tissue-engineered cartilage appears to be a promising alternative. However, due to the complex requirements, the optimal material is yet to be determined. As demonstrated previously, decellularized porcine cartilage (DECM) might be a good option to engineer vital cartilage. As the dense structure of DECM limits cellular infiltration, we investigated surface modifications of the scaffolds by carbon dioxide (CO 2 ) and Er:YAG laser application to facilitate the migration of chondrocytes inside the scaffold. After laser treatment, the scaffolds were seeded with human nasal septal chondrocytes and analyzed with respect to cell migration and formation of new extracellular matrix proteins. Histology, immunohistochemistry, SEM, and TEM examination revealed an increase of the scaffolds' surface area with proliferation of cell numbers on the scaffolds for both laser types. The lack of cytotoxic effects was demonstrated by standard cytotoxicity testing. However, a thermal denaturation area seemed to hinder the migration of the chondrocytes inside the scaffolds, even more so after CO 2 laser treatment. Therefore, the Er:YAG laser seemed to be better suitable. Further modifications of the laser adjustments or the use of alternative laser systems might be advantageous for surface enlargement and to facilitate migration of chondrocytes into the scaffold in one step.

  17. Surface modification and enhanced photocatalytic CO{sub 2} reduction performance of TiO{sub 2}: a review

    Energy Technology Data Exchange (ETDEWEB)

    Low, Jingxiang; Cheng, Bei [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2017-01-15

    Highlights: • Application of modified TiO{sub 2} for photocatalytic CO{sub 2} reduction is summarized. • Different surface modification strategies of TiO{sub 2} are highlighted. • Summary and future perspectives in photocatalytic CO{sub 2} reduction are presented. - Abstract: Recently, the excessive consumption of fossil fuels has caused high emissions of the greenhouse gases, CO{sub 2} into atmosphere and global energy crisis. Mimicking the natural photosynthesis by using semiconductor materials to achieve photocatalytic CO{sub 2} reduction into valuable solar fuels such as CH{sub 4}, HCO{sub 2}H, CH{sub 2}O, and CH{sub 3}OH is known as one of the best solutions for addressing the aforementioned issue. Among various proposed photocatalysts, TiO{sub 2} has been extensively studied over the past several decades for photocatalytic CO{sub 2} reduction because of its cheapness and environmental friendliness. Particularly, surface modification of TiO{sub 2} has attracted numerous interests due to its capability of enhancing the light absorption ability, facilitating the electron-hole separation, tuning the CO{sub 2} reduction selectivity and increasing the CO{sub 2} adsorption and activation ability of TiO{sub 2} for photocatalytic CO{sub 2} reduction. In this review, recent approaches of the surface modification of TiO{sub 2} for photocatalytic CO{sub 2} reduction, including impurity doping, metal deposition, alkali modification, heterojunction construction and carbon-based material loading, are presented. The photocatalytic CO{sub 2} reduction mechanism and pathways of TiO{sub 2} are discussed. The future research direction and perspective of photocatalytic CO{sub 2} reduction over surface-modified TiO{sub 2} are also presented.

  18. Reversible electrochemical modification of the surface of a semiconductor by an atomic-force microscope probe

    Energy Technology Data Exchange (ETDEWEB)

    Kozhukhov, A. S., E-mail: antonkozhukhov@yandex.ru; Sheglov, D. V.; Latyshev, A. V. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    2017-04-15

    A technique for reversible surface modification with an atomic-force-microscope (AFM) probe is suggested. In this method, no significant mechanical or topographic changes occur upon a local variation in the surface potential of a sample under the AFM probe. The method allows a controlled relative change in the ohmic resistance of a channel in a Hall bridge within the range 20–25%.

  19. Modification of the surface properties of a polyimide film during irradiation with polychromic light

    International Nuclear Information System (INIS)

    Rosu, Liliana; Sava, Ion; Rosu, Dan

    2011-01-01

    The behaviour of a polyimide film with the aromatic structure during the exposure to UV light with λ > 290 nm was studied. Significant changes in color surface and gloss surface were identified during irradiation. Sample became lighten and less glossy after exposure to the light. These modifications were correlated with the structural changes in FTIR spectra. Based on changes in FTIR spectra recorded during irradiation, a mechanism for the photochemical degradation of polyimide film was proposed.

  20. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    Energy Technology Data Exchange (ETDEWEB)

    Sodipo, Bashiru Kayode, E-mail: bashirsodipo@gmail.com [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia)

    2016-10-15

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

  1. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    International Nuclear Information System (INIS)

    Sodipo, Bashiru Kayode; Aziz, Azlan Abdul

    2016-01-01

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

  2. Surface modification of biomaterials and biomedical devices using additive manufacturing.

    Science.gov (United States)

    Bose, Susmita; Robertson, Samuel Ford; Bandyopadhyay, Amit

    2018-01-15

    The demand for synthetic biomaterials in medical devices, pharmaceutical products and, tissue replacement applications are growing steadily due to aging population worldwide. The use for patient matched devices is also increasing due to availability and integration of new technologies. Applications of additive manufacturing (AM) or 3D printing (3DP) in biomaterials have also increased significantly over the past decade towards traditional as well as innovative next generation Class I, II and III devices. In this review, we have focused our attention towards the use of AM in surface modified biomaterials to enhance their in vitro and in vivo performances. Specifically, we have discussed the use of AM to deliberately modify the surfaces of different classes of biomaterials with spatial specificity in a single manufacturing process as well as commented on the future outlook towards surface modification using AM. It is widely understood that the success of implanted medical devices depends largely on favorable material-tissue interactions. Additive manufacturing has gained traction as a viable and unique approach to engineered biomaterials, for both bulk and surface properties that improve implant outcomes. This review explores how additive manufacturing techniques have been and can be used to augment the surfaces of biomedical devices for direct clinical applications. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. The increase of apatite layer formation by the poly(3-hydroxybutyrate) surface modification of hydroxyapatite and β-tricalcium phosphate.

    Science.gov (United States)

    Szubert, M; Adamska, K; Szybowicz, M; Jesionowski, T; Buchwald, T; Voelkel, A

    2014-01-01

    The aim of this study was the surface modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) grafting and characterization of modificates. The bioactivity examination was carried out by the determination to grow an apatite layer on modified materials during incubation in simulated body fluid at 37°C. The additional issue taken up in this paper was to investigate the influence of fluid replacement. The process of the surface modification of biomaterials was evaluated by means of infrared and Raman spectroscopy. Formation of the apatite layer was assessed by means of scanning electron microscopy and confirmed by energy dispersive, Raman and Fourier transformed infrared spectroscopy. During exposure in simulated body fluid, the variation of the zeta potential, pH measurement and relative weight was monitored. Examination of scanning electron microscopy micrographs suggests that modification of hydroxyapatite and β-tricalcium phosphate by poly(3-hydroxybutyrate) significantly increases apatite layer formation. Raman spectroscopy evaluation revealed that the formation of the apatite layer was more significant in the case of hydroxyapatite modificate, when compared to the β-tricalcium phosphate modificate. Both modificates were characterized by stable pH, close to the natural pH of human body fluids. Furthermore, we have shown that a weekly changed, simulated body fluid solution increases apatite layer formation. © 2013.

  4. Inhibition of charge recombination for enhanced dye-sensitized solar cells and self-powered UV sensors by surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Liang, E-mail: chuliang@njupt.edu.cn [Advanced Energy Technology Center, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); Qin, Zhengfei; Liu, Wei [School of Materials Science and Engineering (SMSE), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Ma, Xin’guo, E-mail: maxg2013@sohu.com [Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan 430068 (China)

    2016-12-15

    Graphical abstract: Inhibition of charge recombination was utilized to prolong electrode lifetime in dye-sensitized solar cells (DSSCs) and self-powered UV sensors based on TiO{sub 2}-modified SnO{sub 2} photoelectrodes. The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the electron lifetime was significantly prolonged in DSSCs after TiO{sub 2} modification. And in self-powered UV sensors, the sensitivity and response time were enhanced. - Highlights: • The surface modification to inhibit charge recombination was utilized in photovoltaic devices. • Inhibition of charge recombination can prolong electrode lifetime in photovoltaic devices. • Enhanced DSSCs and self-powered UV sensors based on SnO{sub 2} photoelectrodes were obtained by TiO{sub 2} modification. - Abstract: The surface modification to inhibit charge recombination was utilized in dye-sensitized solar cells (DSSCs) and self-powered ultraviolet (UV) sensors based on SnO{sub 2} hierarchical microspheres by TiO{sub 2} modification. For DSSCs with SnO{sub 2} photoelectrodes modified by TiO{sub 2}, the power conversion efficiency (PCE) was improved from 1.40% to 4.15% under standard AM 1.5G illumination (100 mW/cm{sup 2}). The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the charge recombination was effectively inhibited, resulting in long electron lifetime. For UV sensors with SnO{sub 2} photoelectrodes modified by TiO{sub 2} layer, the self-powered property was more obvious, and the sensitivity and response time were enhanced from 91 to 6229 and 0.15 s to 0.055 s, respectively. The surface modification can engineer the interface energy to inhibit charge recombination, which is a desirable approach to improve the performance of photoelectric nanodevice.

  5. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    Science.gov (United States)

    da Maia, J. V.; Pereira, F. P.; Dutra, J. C. N.; Mello, S. A. C.; Becerra, E. A. O.; Massi, M.; Sobrinho, A. S. da Silva

    2013-11-01

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (CO, COC and CO) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  6. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    International Nuclear Information System (INIS)

    Maia, J.V. da; Pereira, F.P.; Dutra, J.C.N.; Mello, S.A.C.; Becerra, E.A.O.; Massi, M.; Sobrinho, A.S. da Silva

    2013-01-01

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (C-O, C-O-C and C=O) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  7. Influence of gas and treatment time on the surface modification of EPDM rubber treated at afterglow microwave plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Maia, J.V. da, E-mail: jaisondamaia@hotmail.com [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil); Department of Physics, Federal Institute of Santa Catarina, 89251-000 Jaraguá do Sul, SC (Brazil); Pereira, F.P. [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil); Dutra, J.C.N.; Mello, S.A.C. [EBO, Chemistry Division, IAE, CTA, 12228-900 S. J. dos Campos, SP (Brazil); Becerra, E.A.O. [Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Massi, M.; Sobrinho, A.S. da Silva [Plasmas and Processes Laboratory, Department of Physics, Technological Institute of Aeronautics, 12228-900 S. J. dos Campos, SP (Brazil)

    2013-11-15

    The ethylene propylene diene monomer (EPDM) rubber possesses excellent physical/chemical bulk properties, is cost-effective, and has been used in the mechanical and aerospace industry. However, it has an inert surface and needs a surface treatment in order to improve its adhesion properties. Plasma modification is the most accepted technique for surface modification of polymers without affecting the properties of the bulk. In this study, an afterglow microwave plasma reactor was used to generate the plasma species responsible for the EPDM surface modification. The plasma modified surfaces were analyzed by means of contact angle measurement, adhesion tests, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. Two experimental variables were analyzed: type of the plasma gases and exposure time were considered. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed and the best conditions tested there was an increase of the rupture strength of about 27%, that can be associated mainly with the creation of oxygen containing functional groups on the rubber surface (C-O, C-O-C and C=O) identified by spectroscopic methods. The predominant failure mode was adhesive, for long treatment times a mixture of adhesive and cohesive failure can be observed. In various conditions tested the contact angles easily decreased more than 500%. What can be concluded that high wettability is a necessary condition to obtain good adhesion, but this is not a sufficient condition.

  8. Influence of Different Surface Modifications on the Photovoltaic Performance and Dark Current of Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    XU Weiwei; DAI Songyuan; HU Linhua; ZHANG Changneng; XIAO Shangfeng; LUO Xiangdong; JING Weiping; WANG Kongjia

    2007-01-01

    The TiO2 nanoporous film photoelectrode, as a crucial component of dye-sensitized solar cells, has been investigated. The photovoltaic properties and the dark current were studied by two surface modification methods. One was to apply a compact layer between the conductive glass substrate and nanoporous TiO2 film. Another was to produce TiO2 nanoparticles among the microstructure by TiCU treatment. A suitable concentration and number of times for TiCU treatment were found in our experiment. The dark current is suppressed by surface modifications, leading to a significant improvement in the solar cells performance. An excessive concentration of TiCU will produce more surface states and introduce a larger dark current reversely. The dye is also regarded as a source of charge recombination in dark to some extent, due to an amount of surface protonations introduced by the interfacial link in the conductive glass substrate/dye interface and dye/TiO2 interface.

  9. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Science.gov (United States)

    Moraczewski, Krzysztof; Rytlewski, Piotr; Malinowski, Rafał; Żenkiewicz, Marian

    2015-08-01

    The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm2 was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  10. One-step surface modification of poly(dimethylsiloxane) by undecylenic acid

    Science.gov (United States)

    Zhou, Jinwen; McInnes, Steven J. P.; Md Jani, Abdul Mutalib; Ellis, Amanda V.; Voelcker, Nicolas H.

    2008-12-01

    Poly(dimethylsiloxane) (PDMS) is a popular material for microfluidic devices due to its relatively low cost, ease of fabrication, oxygen permeability and optical transmission characteristics. However, its highly hydrophobic surface is still the main factor limiting its wide application, in particular as a material for biointerfaces. A simple and rapid method to form a relatively stable hydrophilised PDMS surface is reported in this paper. The PDMS surface was treated with pure undecylenic acid (UDA) for 10 min, 1 h and 1 day at 80 °C in a sealed container. The effects of the surface modification were investigated using water contact angle (WCA) measurements, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), and streaming zeta-potential analysis. The water contact angle of 1 day UDAmodified PDMS was found to decrease from that of native PDMS (110 °) to 75 °, demonstrating an increase in wettability of the surface. A distinctive peak at 1715 cm-1 in the FTIR-ATR spectra after UDA treatment was representative of carboxylation of the PDMS surface. The measured zeta-potential (ζ) at pH 4 changed from -27 mV for pure PDMS to -19 mV after UDA treatment. In order to confirm carboxylation of the surface visually, Lucifer Yellow CH fluorescence dye was reacted via a condensation reaction to the 1 day UDA modified PDMS surface. Fluorescent microscopy showed Lucifer Yellow CH fluorescence on the carboxylated surface, but not on the pure PDMS surface. Stability experiments were also performed showing that 1 day modified UDA samples were stable in both MilliQ water at 50 °C for 17 h, and in a desiccator at room temperature for 19.5 h.

  11. Microstructural evolution and surface properties of nanostructured Cu-based alloy by ultrasonic nanocrystalline surface modification technique

    Energy Technology Data Exchange (ETDEWEB)

    Amanov, Auezhan, E-mail: amanov_a@yahoo.com [Department of Mechanical Engineering, Sun Moon University, Asan 336-708 (Korea, Republic of); Cho, In-Sik [R& D Group, Mbrosia Co., Ltd., Asan 336-708 (Korea, Republic of); Pyun, Young-Sik [Department of Mechanical Engineering, Sun Moon University, Asan 336-708 (Korea, Republic of)

    2016-12-01

    Graphical abstract: - Highlights: • A nanostructured surface was produced by UNSM technique. • Porosities were eliminated from the surface by UNSM technique. • Extremely high hardness obtained at the top surface after UNSM treatment. • Friction and wear behavior was improved by UNSM technique. • Resistance to scratch behavior was improved by UNSM technique. - Abstract: A nanostructured surface layer with a thickness of about 180 μm was successfully produced in Cu-based alloy using an ultrasonic nanocrystalline surface modification (UNSM) technique. Cu-based alloy was sintered onto low carbon steel using a powder metallurgy (P/M) method. Transmission electron microscope (TEM) characterization revealed that the severe plastic deformation introduced by UNSM technique resulted in nano-sized grains in the topmost surface layer and deformation twins. It was also found by atomic force microscope (AFM) observations that the UNSM technique provides a significant reduction in number of interconnected pores. The effectiveness of nanostructured surface layer on the tribological and micro-scratch properties of Cu-based alloy specimens was investigated using a ball-on-disk tribometer and micro-scratch tester, respectively. Results exhibited that the UNSM-treated specimen led to an improvement in tribological and micro-scratch properties compared to that of the sintered specimen, which may be attributed to the presence of nanostructured surface layer having an increase in surface hardness and reduction in surface roughness. The findings from this study are expected to be implemented to the automotive industry, in particular connected rod bearings and bushings in order to increase the efficiency and performance of internal combustion engines (ICEs).

  12. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang Sha [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Wang Yijuan [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Deng, Tianzheng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Jin Fang [Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi' an, 710032 (China); Liu Shouxin [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Zhang Yongjie [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Feng Feng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Jin Yan [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China)], E-mail: yanjin@fmmu.edu.cn

    2008-07-28

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 {mu}m) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering.

  13. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    International Nuclear Information System (INIS)

    Huang Sha; Wang Yijuan; Deng, Tianzheng; Jin Fang; Liu Shouxin; Zhang Yongjie; Feng Feng; Jin Yan

    2008-01-01

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 μm) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering

  14. Surface modification of quartz fibres for dental composites through a sol-gel process.

    Science.gov (United States)

    Wang, Yazi; Wang, Renlin; Habib, Eric; Wang, Ruili; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2017-05-01

    In this study, quartz fibres (QFs) surface modification using a sol-gel method was proposed and dental posts reinforced with modified QFs were produced. A silica sol (SS) was prepared using tetraethoxysilane (TEOS) and 3-methacryloxypropyltrimethoxysilane (γ-MPS) as precursors. The amount of γ-MPS in the sol-gel system was varied from 0 to 24wt.% with a constant molar ratio of TEOS, ethanol, deionized water, and HCl. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and contact angle (CA) measurements were used to characterize the modified QFs, which confirmed that SS had successfully coated the surface of QFs. SEM images showed good interfacial bonding between the modified QFs and the resin matrix. The results of three-point bending tests of the fibre reinforced composite (FRC) posts showed that the QFs modified by SS with 12wt.% γ-MPS presented the best mechanical properties, demonstrating improvements of 108.3% and 89.6% for the flexural strength and flexural modulus, respectively, compared with untreated QFs. Furthermore, the sorption and solubility of the prepared dental posts were also studied by immersing the posts in artificial saliva (AS) for 4weeks, and yielded favourable results. This sol-gel surface modification method promises to resolve interfacial bonding issues of fibres with the resin matrix, and produce FRC posts with excellent properties. Copyright © 2017. Published by Elsevier B.V.

  15. Surface modification to produce hydrophobic nano-silica particles using sodium dodecyl sulfate as a modifier

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Bing; Liang, Yong; Wang, Ting-Jie, E-mail: wangtj@tsinghua.edu.cn; Jiang, Yanping

    2016-02-28

    Graphical abstract: Nano silica particle was modified to produce hydrophobic surface with contact angle of 107° using the water soluble SDS as a modifier through a new route. The grafted density reached 1.82–2 nm. Brønsted acid sites supply proton to react with SDS via generating carbocation, forming a Si–O–C structure. - Highlights: • Silica was modified to produce hydrophobic surface using SDS as modifier. • The route is free of organic solvent and gets perfect contact of SDS and silica. • Contact angle of modified silica particles reached 107°. • Grafted density on the silica surface reached 1.82 SDS nm{sup −2}. • Brønsted acid sites supply proton to react with SDS via generating carbocation. - Abstract: Hydrophobic silica particles were prepared using the surfactant sodium dodecyl sulfate (SDS) as a modifier by a new route comprising three processes, namely, aqueous mixing, spray drying and thermal treatment. Since SDS dissolves in water, this route is free of an organic solvent and gave a perfect dispersion of SDS, that is, there was excellent contact between SDS and silica particles in the modification reaction. The hydrophobicity of the modified surface was verified by the contact angle of the nano-sized silica particles, which was 107°. The SDS grafting density reached 1.82 nm{sup −2}, which is near the highest value in the literature. The optimal parameters of the SDS/SiO{sub 2} ratio in the aqueous phase, process temperature and time of thermal treatment were determined to be 20%, 200 °C and 30 min, respectively. The grafting mechanism was studied by comparing the modification with that on same sized TiO{sub 2} particles, which indicated that the protons of the Brønsted acid sites on the surface of SiO{sub 2} reacted with SDS to give a carbocation which then formed a Si–O–C structure. This work showed that the hydrophilic surface of silica can be modified to be a hydrophobic surface by using a water soluble modifier SDS in a

  16. Plasma treatment induces internal surface modifications of electrospun poly(L-lactic) acid scaffold to enhance protein coating

    International Nuclear Information System (INIS)

    Jin Seo, Hyok; Hee Lee, Mi; Kwon, Byeong-Ju; Kim, Hye-Lee; Park, Jong-Chul; Jin Lee, Seung; Kim, Bong-Jin; Wang, Kang-Kyun; Kim, Yong-Rok

    2013-01-01

    Advanced biomaterials should also be bioactive with regard to desirable cellular responses, such as selective protein adsorption and cell attachment, proliferation, and differentiation. To enhance cell-material interactions, surface modifications have commonly been performed. Among the various surface modification approaches, atmospheric pressure glow discharge plasma has been used to change a hydrophobic polymer surface to a hydrophilic surface. Poly(L-lactic acid) (PLLA)-derived scaffolds lack cell recognition signals and the hydrophobic nature of PLLA hinders cell seeding. To make PLLA surfaces more conducive to cell attachment and spreading, surface modifications may be used to create cell-biomaterial interfaces that elicit controlled cell adhesion and maintain differentiated phenotypes. In this study, (He) gaseous atmospheric plasma glow discharge was used to change the characteristics of a 3D-type polymeric scaffold from hydrophobic to hydrophilic on both the outer and inner surfaces of the scaffold and the penetration efficiency with fibronectin was investigated. Field-emission scanning electron microscope images showed that some grooves were formed on the PLLA fibers after plasma treatment. X-ray photoelectron spectroscopy data also showed chemical changes in the PLLA structure. After plasma treatment, -CN (285.76 eV) was increased in C1s and -NH 2 (399.70 eV) was increased significantly and –N=CH (400.80 eV) and –NH 3 + (402.05 eV) were newly appeared in N1s. These changes allowed fibronectin to penetrate into the PLLA scaffold; this could be observed by confocal microscopy. In conclusion, helium atmospheric pressure plasma treatment was effective in modifying the polymeric scaffold, making it hydrophilic, and this treatment can also be used in tissue engineering research as needed to make polymers hydrophilic

  17. The influence of surface modification on sound absorption coefficient of albizzia wood absorber

    Science.gov (United States)

    Diharjo, Kuncoro; Prabowo, Anditya E.; Jamasri, Suharty, Neng Sri

    2017-01-01

    The purpose of this research is to investigate the influence of surface modification to sound absorption on absorber based albizia wood and kenaf fiber. The absorber was produced using the albizia wood as main materials, and the kenaf fiber was used as acoustic fill. The albizia wood used for producing the absorber was cut in the transverse direction so that its surface had good porosity. The size of specimens had 100 mm in diameter and 40 mm in thickness. The configuration of resonator cavities was 30 mm in diameter and 20 mm in depth, and each resonator was completed with a neck hole of the resonator. The types of surface modification were the addition of screen printing ink, fabric (with and without neck hole), and vinyl-wallpaper (with and without neck hole). According to ISO 10534-2, the absorber specimens were tested using two microphones impedance tube with random noise source to get the curve of noise absorption coefficient (NAC) for each specimen. The result shows that both unmodified absorber and absorber modified with screen printing ink have the similar characteristic of NAC and they are feasible to be used as an absorber in conversation rooms. The addition of fabric and vinyl-wallpaper as cover on the absorber surface give the positive effect of the air gap, and it increases the NAC in low frequency (100-400 Hz). However, the covers decrease the NAC in high frequency (400-1,400 Hz). The holes on the fabric and wallpaper covers give the improvement of NAC.

  18. Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal.

    Science.gov (United States)

    Li, Lin; Liu, Suqin; Liu, Junxin

    2011-08-30

    In this study, coconut shell based carbons were chemically treated by ammonia, sodium hydroxide, nitric acid, sulphuric acid, and phosphoric acid to determine suitable modification for improving adsorption ability of hydrophobic volatile organic compounds (VOCs) on granular activated carbons (GAC). The saturated adsorption capacities of o-xylene, a hydrophobic volatile organic compound, were measured and adsorption effects of the original and modified activated carbons were compared. Results showed that GAC modified by alkalis had better o-xylene adsorption capacity. Uptake amount was enhanced by 26.5% and reduced by 21.6% after modification by NH(3)H(2)O and H(2)SO(4), respectively. Compared with the original, GAC modified by acid had less adsorption capacity. Both SEM/EDAX and BET were used to identify the structural characteristics of the tested GAC, while IR spectroscopy and Boehm's titration were applied to analysis the surface functional groups. Relationships between physicochemical characteristics of GAC and their adsorption performances demonstrated that o-xylene adsorption capacity was related to surface area, pore volume, and functional groups of the GAC surface. Removing surface oxygen groups, which constitute the source of surface acidity, and reducing hydrophilic carbon surface favors adsorption capacity of hydrophobic VOCs on carbons. The performances of modified GACs were also investigated in the purification of gases containing complex components (o-xylene and steam) in the stream. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Surface modification of a proton exchange membrane and hydrogen storage in a metal hydride for fuel cells

    Science.gov (United States)

    Andrews, Lisa

    Interest in fuel cell technology is rising as a result of the need for more affordable and available fuel sources. Proton exchange membrane fuel cells involve the catalysis of a fuel to release protons and electrons. It requires the use of a polymer electrolyte membrane to transfer protons through the cell, while the electrons pass through an external circuit, producing electricity. The surface modification of the polymer, NafionRTM, commonly researched as a proton exchange membrane, may improve efficiency of a fuel cell. Surface modification can change the chemistry of the surface of a polymer while maintaining bulk properties. Plasma modification techniques such as microwave discharge of an argon and oxygen gas mixture as well as vacuum-ultraviolet (VUV) photolysis may cause favorable chemical and physical changes on the surface of Nafion for improved fuel cell function. A possible increase in hydrophilicity as a result of microwave discharge experiments may increase proton conductivity. Grafting of acrylic acid from the surface of modified Nafion may decrease the permeation of methanol in a direct methanol fuel cell, a process which can decrease efficiency. Modification of the surface of Nafion samples were carried out using: 1) An indirect Ar/O2 gas mixture plasma investigating the reaction of oxygen radicals with the surface, 2) A direct Ar/O2 gas mixture plasma investigating the reaction of oxygen radicals and VUV radiation with the surface and, 3) VUV photolysis investigating exclusively the interaction of VUV radiation with the surface and any possible oxidation upon exposure to air. Acrylic acid was grafted from the VUV photolysed Nafion samples. All treated surfaces were analyzed using X-ray photoelectron spectroscopy (XPS). Fourier transform infrared spectroscopy (FTIR) was used to analyze the grafted Nafion samples. Scanning electron microscopy (SEM) and contact angle measurements were used to analyze experiments 2 and 3. Using hydrogen as fuel is a

  20. Surface Modification of Zinc with an Oxime for Corrosion Protection in Chloride Medium

    Directory of Open Access Journals (Sweden)

    Ganesha Achary

    2013-01-01

    Full Text Available The surface treatment of zinc was done with different concentrations of an oxime (2E-2-(hydroxylamino-1,2-diphenylethanol molecule by the immersion method. The electrochemical corrosion studies of surface-treated zinc specimens were performed in aqueous sodium chloride solution (1 M, pH 5.0 at different temperatures in order to study the corrosion mechanism. The recorded electrochemical data indicated a basic modification of the cathodic corrosion behavior of the treated zinc resulting in a decrease of the electron transfer rate. The zinc samples treated by immersion in the inhibiting organic solution presented good corrosion resistance. Using scanning electron microscopy (SEM, it was found that a protective film was formed on the surface of zinc.

  1. Transport of particles by surface waves: a modification of the classical bouncer model

    International Nuclear Information System (INIS)

    Ragulskis, M; Sanjuan, M A F

    2008-01-01

    We consider a ball under the influence of gravity on a platform. A propagating surface wave travels on the surface of the platform, while the platform remains motionless. This is a modification of the classical bouncing ball problem and describes the transport of particles by surface waves. Phase and velocity maps cannot be expressed in an explicit form owing to implicit formulations, and no formal analytical analysis is possible. Numerical analysis shows that the transition to chaos is produced via a period doubling route, which is a common property for classical bouncers. The bouncing process can be sensitive to the initial conditions, which can build the ground for control techniques that can dramatically increase the effectiveness of particle transport in practical applications

  2. Use of Intense Ion Beams for Surface Modification and Creation of New Materials

    CERN Document Server

    Renk, T; Prasad, S V; Provencio, P P; Thompson, M

    2002-01-01

    We have conducted surface treatment and alloying experiments with Al, Fe, and Ti-based metals on the RHEPP-1 accelerator (0.8 MV, 20 W, 80 ns FHWM, up to 1 Hz repetition rate) at Sandia National Laboratories. Ions are generated by the MAP gas-breakdown active anode, which can yield a number of different beam species including H, N, and C, depending upon the injected gas. Beams of intense pulsed high-power ion beams have been used to produce surface modification by changes in microstructure caused by rapid heating and cooling of the surface. Increase of beam power leads to ablation of a target surface, and redeposition of ablated material onto a separate substrate. Experiments are described in which ion beams are used in an attempt to increase high-voltage breakdown of a treated surface. Surface alloying of coated Pt and Hf layers is also described. This mixing of a previously deposited thin-film layer into a Ti-alloy substrate leads to significantly enhanced surface wear durability, compared to either untreat...

  3. Ultraviolet light and ozone surface modification of poly-alpha α-methylstyrene using electroless nickel plating

    International Nuclear Information System (INIS)

    Chi Fangting; Sichuan Univ., Chengdu; Li Bo; Liu Yiyang; Chen Sufen; Jiang Bo

    2009-01-01

    The deposition capability of nickel on the surface of poly-α-methylstyrene microspheres was improved by combined treatment of ozone aeration and UV irradiation in aqueous ammonia. Surface properties of the treated film were investigated by X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FT-TR) measurements. The samples were characterized by SEM. The results indicate that after ultraviolet joint ozone treatment, the surfaces of microspheres were oxidized, and the amine and amide groups are introduced on their surface. The images of SEM show the adhesion between microspheres and nickel-phosphorus films was improved after surface modification. This was attributed to amide which could chemisorb palladium ions to catalyze electroless nickel plating on the pretreated surface of microspheres. (authors)

  4. Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification.

    Science.gov (United States)

    Lassnig, R; Hollerer, M; Striedinger, B; Fian, A; Stadlober, B; Winkler, A

    2015-11-01

    In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p ++ -silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

  5. Laser Surface Modification of H13 Die Steel using Different Laser Spot Sizes

    Science.gov (United States)

    Aqida, S. N.; Naher, S.; Brabazon, D.

    2011-05-01

    This paper presents a laser surface modification process of AISI H13 tool steel using three sizes of laser spot with an aim to achieve reduced grain size and surface roughness. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). Metallographic study and image analysis were done to measure the grain size and the modified surface roughness was measured using two-dimensional surface profilometer. From metallographic study, the smallest grain sizes measured by laser modified surface were between 0.51 μm and 2.54 μm. The minimum surface roughness, Ra, recorded was 3.0 μm. This surface roughness of the modified die steel is similar to the surface quality of cast products. The grain size correlation with hardness followed the findings correlate with Hall-Petch relationship. The potential found for increase in surface hardness represents an important method to sustain tooling life.

  6. Pretreatment and Membrane Hydrophilic Modification to Reduce Membrane Fouling

    Directory of Open Access Journals (Sweden)

    Huaqiang Chu

    2013-09-01

    Full Text Available The application of low pressure membranes (microfiltration/ultrafiltration has undergone accelerated development for drinking water production. However, the major obstacle encountered in its popularization is membrane fouling caused by natural organic matter (NOM. This paper firstly summarizes the two factors causing the organic membrane fouling, including molecular weight (MW and hydrophilicity/hydrophobicity of NOM, and then presents a brief introduction of the methods which can prevent membrane fouling such as pretreatment of the feed water (e.g., coagulation, adsorption, and pre-oxidation and membrane hydrophilic modification (e.g., plasma modification, irradiation grafting modification, surface coating modification, blend modification, etc.. Perspectives of further research are also discussed.

  7. Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Guo Xiaojun, E-mail: guoxj6906@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China); Zhao Leihua; Zhang Li; Li Jing [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China)

    2012-01-15

    Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108 Degree-Sign and a well dispersion.

  8. Peri- and intra-implant bone response to microporous Ti coatings with surface modification.

    Science.gov (United States)

    Braem, Annabel; Chaudhari, Amol; Vivan Cardoso, Marcio; Schrooten, Jan; Duyck, Joke; Vleugels, Jozef

    2014-02-01

    Bone growth on and into implants exhibiting substantial surface porosity is a promising strategy in order to improve the long-term stable fixation of bone implants. However, the reliability in clinical applications remains a point of discussion. Most attention has been dedicated to the role of macroporosity, leading to the general consensus of a minimal pore size of 50-100 μm in order to allow bone ingrowth. In this in vivo study, we assessed the feasibility of early bone ingrowth into a predominantly microporous Ti coating with an average thickness of 150 μm and the hypothesis of improving the bone response through surface modification of the porous coating. Implants were placed in the cortical bone of rabbit tibiae for periods of 2 and 4 weeks and evaluated histologically and histomorphometrically using light microscopy and scanning electron microscopy. Bone with osteocytes encased in the mineralized matrix was found throughout the porous Ti coating up to the coating/substrate interface, highlighting that osseointegration of microporosities (coating in the host bone in the long term is possible. When surface modifications inside the porous structure further reduced the interconnective pore size to the submicrometer level, bone ingrowth was impaired. On the other hand, application of a sol-gel-derived bioactive glass-ceramic coating without altering the pore characteristics was found to significantly improve bone regeneration around the coating, while still supporting bone ingrowth. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Surface modification of polysulfone membranes applied for a membrane reactor with immobilized alcohol dehydrogenase

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Silau, Harald; Pinelo, Manuel

    2018-01-01

    activated by lithiation followed by functionalization with acid chlorides at 0 °C, permitting modification of commercial PSf membranes without compromising the mechanical integrity of the membrane. Post-functionalization polymer grafting was illustrated through both, a “grafting from” approach by surface...... initiated atom transfer radical polymerization (SI-ATRP) and by a “grafting to” approach exploiting Cu(I) catalyzed 1,3-cycloadditions of alkynes with azides (CuAAC) introducing hydrophilic polymers onto the membrane surface. Poly(1-vinyl imidazole) (pVim) grafted membranes were exploited as support...

  10. The surface modifications of multi-walled carbon nanotubes for multi-walled carbon nanotube/poly(ether ether ketone) composites

    International Nuclear Information System (INIS)

    Cao, Zongshuang; Qiu, Li; Yang, Yongzhen; Chen, Yongkang; Liu, Xuguang

    2015-01-01

    Graphical abstract: Multi-walled carbon nanotube/poly(ether ether ketone) (MWCNT/PEEK) composites incorporating surface modified multi-walled carbon nanotubes (MWCNTs) as fillers were fabricated in a solution blending method in order to explore the dynamic mechanical and tribological properties of MWCNT/PEEK composites systematically. It is evident that surface modifications of MWCNTs have a significant impact on dispersibility of MWCNTs in PEEK, dynamic mechanical and tribological properties of MWCNT/PEEK composites. Typically, a clear effect of surface modifications of MWCNTs on tribological properties of MWCNT/PEEK composites was observed. A significant reduction in frictional coefficient of MWCNT/PEEK composites with the MWCNTs modified with ethanolamine has been achieved and the self-lubricating film on their worn surfaces was also observed. - Highlights: • The dispersibility of surface modified MWCNTs in PEEK has been studied. • MWCNTs modified with ethanolamine have showed a good dispersion in PEEK. • Surface modifications of MWCNTs have a significant impact on both dynamic mechanical and tribological properties of MWCNT/PEEK composites. - Abstract: The effects of surface modifications of multi-walled carbon nanotubes (MWCNTs) on the morphology, dynamic mechanical and tribological properties of multi-walled carbon nanotube/poly(ether ether ketone) (MWCNT/PEEK) composites have been investigated. MWCNTs were treated with mixed acids to obtain acid-functionalized MWCNTs. Then the acid-functionalized MWCNTs were modified with ethanolamine (named e-MWCNTs). The MWCNT/PEEK composites were prepared by a solution-blending method. A more homogeneous distribution of e-MWCNTs within the composites was found with scanning electron microscopy. Dynamic mechanical analysis demonstrated a clear increase in the storage modulus of e-MWCNT/PEEK composites because of the improved interfacial adhesion strength between e-MWCNTs and PEEK. Furthermore, the presence of e

  11. The surface modifications of multi-walled carbon nanotubes for multi-walled carbon nanotube/poly(ether ether ketone) composites

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zongshuang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Research Center of Advanced Material Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Qiu, Li [Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yang, Yongzhen, E-mail: yyztyut@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Research Center of Advanced Material Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Chen, Yongkang, E-mail: y.k.chen@herts.ac.uk [Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); University of Hertfordshire, School of Engineering and Technology, Hatfield, Hertfordshire AL10 9AB (United Kingdom); Liu, Xuguang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-10-30

    Graphical abstract: Multi-walled carbon nanotube/poly(ether ether ketone) (MWCNT/PEEK) composites incorporating surface modified multi-walled carbon nanotubes (MWCNTs) as fillers were fabricated in a solution blending method in order to explore the dynamic mechanical and tribological properties of MWCNT/PEEK composites systematically. It is evident that surface modifications of MWCNTs have a significant impact on dispersibility of MWCNTs in PEEK, dynamic mechanical and tribological properties of MWCNT/PEEK composites. Typically, a clear effect of surface modifications of MWCNTs on tribological properties of MWCNT/PEEK composites was observed. A significant reduction in frictional coefficient of MWCNT/PEEK composites with the MWCNTs modified with ethanolamine has been achieved and the self-lubricating film on their worn surfaces was also observed. - Highlights: • The dispersibility of surface modified MWCNTs in PEEK has been studied. • MWCNTs modified with ethanolamine have showed a good dispersion in PEEK. • Surface modifications of MWCNTs have a significant impact on both dynamic mechanical and tribological properties of MWCNT/PEEK composites. - Abstract: The effects of surface modifications of multi-walled carbon nanotubes (MWCNTs) on the morphology, dynamic mechanical and tribological properties of multi-walled carbon nanotube/poly(ether ether ketone) (MWCNT/PEEK) composites have been investigated. MWCNTs were treated with mixed acids to obtain acid-functionalized MWCNTs. Then the acid-functionalized MWCNTs were modified with ethanolamine (named e-MWCNTs). The MWCNT/PEEK composites were prepared by a solution-blending method. A more homogeneous distribution of e-MWCNTs within the composites was found with scanning electron microscopy. Dynamic mechanical analysis demonstrated a clear increase in the storage modulus of e-MWCNT/PEEK composites because of the improved interfacial adhesion strength between e-MWCNTs and PEEK. Furthermore, the presence of e

  12. Phase modification and surface plasmon resonance of Au/WO{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Bose, R. Jolly; Kavitha, V.S. [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram 691574, Kerala (India); Sudarsanakumar, C. [School of Pure and Applied Physics, Mahatma Gandhi University, Priyadarshini Hills, Kottayam 686560, Kerala (India); Pillai, V.P. Mahadevan, E-mail: vpmpillai9@gmail.com [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram 691574, Kerala (India)

    2016-08-30

    Highlights: • We have investigated the role of gold as catalyst and nucleation centers, for the crystallization and phase modification of tungsten oxide, in Au/WO{sub 3} matrix. • The phase change from triclinic WO{sub 3} to monoclinic W{sub 18}O{sub 49} is found to enhance with gold incorporation. • The surface plasmon resonance is observed in gold/tungsten oxide system with the appearance of an absorption band near the wavelength 604 nm. - Abstract: We report the action of gold as catalyst for the modification of phase from triclinic WO{sub 3} to monoclinic W{sub 18}O{sub 49} and nucleation centre for the formation of W{sub 18}O{sub 49} phase, in gold incorporated tungsten oxide films prepared by RF magnetron sputtering technique. A new band is observed near 925 cm{sup −1} in the Raman spectra of gold incorporated tungsten oxide films which is not observed in the pure tungsten oxide film. The intensity of this band enhances with gold content. A localized surface plasmon resonance (LSPR) band is observed near the wavelength 604 nm in gold incorporated tungsten oxide films. The integrated intensities of LSPR band and Raman band (∼925 cm{sup −1}) can be used for sensing the quantity of gold in the Au/WO{sub 3} matrix.

  13. Surface modification and particles size distribution control in nano-CdS/polystyrene composite film

    International Nuclear Information System (INIS)

    Min Zhirong; Ming Qiuzhang; Hai Chunliang; Han Minzeng

    2003-01-01

    Preparation of nano-CdS particles with surface thiol modification by microemulsion method and their influences on the particle size distribution in highly filled polystyrene-based composites were studied. The modified nano-CdS was characterized by X-ray photoelectron spectroscopy (XPS), light absorption and emission measurements to reveal the morphologies of the surface modifier, which are consistent with the surface molecules packing calculation. The morphologies of the surface modifier exerted a great influence not only on the optical performance of the particles themselves, but also on the size distribution of the particle in polystyrene matrix. A monolayer coverage with tightly packed thiol molecules was believed to be most effective in promoting a uniform particle size distribution and eliminating the surface defects that cause radiationless recombination. Control of the particles size distribution in polystyrene can be attained by adjusting surface coverage status of the thiol molecules based on the strong interaction between the surface modifier and the matrix

  14. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, ul. M. Skłodowskiej–Curie 55, 87-100 Toruń (Poland); Żenkiewicz, Marian [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland)

    2015-08-15

    Highlights: • We modified polylactide surface layer with chemical, plasma or laser methods. • We tested selected properties and surface structure of modified samples. • We stated that the plasma treatment appears to be the most beneficial. - Abstract: The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm{sup 2} was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  15. The effect of fluoride surface modification of ceramic TiO{sub 2} on the surface properties and biological response of osteoblastic cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tiainen, H; Knychala, J; Lyngstadaas, S P; Haugen, H J [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, PO Box 1109 Blindern, NO-0317 Oslo (Norway); Monjo, M [Department of Fundamental Biology and Health Sciences, Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, Cra. de Valldemossa, km 7.5, 07122 Palma de Mallorca (Spain); Nilsen, O [Department of Chemistry, University of Oslo, PO Box 1033 Blindern, NO-0315 Oslo (Norway); Ellingsen, J E, E-mail: h.j.haugen@odont.uio.no [Oral Research Laboratory, Institute for Clinical Dentistry, University of Oslo, PO Box 1109 Blindern, NO-0317 Oslo (Norway)

    2011-08-15

    This study investigates the effect of fluoride surface modification on the surface properties of polycrystalline ceramic TiO{sub 2} and the biological response of murine osteoblast cells to fluoride-modified TiO{sub 2} in vitro. Fluoride concentrations up to 9 at.% were detected and the fluoride was found to bind to the surface in a ligand exchange reaction between surface hydroxyl groups and the fluoride anions from the HF. No significant changes in the surface topography were detected. In vitro experiments were performed in order to evaluate the biological response of the MC3T3-E1 cells to the fluoride-modified ceramic TiO{sub 2} surfaces. No difference in the lactate dehydrogenase (LDH) activity was seen in comparison to unmodified samples, apart from the highest fluoride concentration ({approx}9 at.%) which was found to be more toxic to the cells. Real-time PCR analysis showed no conclusive evidence for the fluoride-induced promotion of osteoblast differentiation as no significant increase in the collagen-1, osteocalcin, or BMP-2 mRNA levels was detected on the fluoride-modified ceramic TiO{sub 2} surfaces apart from one group, which showed an elevated osteocalcin level and higher number of cells. Since the observed grain boundary corrosion is also anticipated to reduce the mechanical properties of ceramic TiO{sub 2}, this surface modification method may not be an ideal method for improving the osteogenic response of ceramic TiO{sub 2} scaffolds.

  16. Uniform surface modification of diatomaceous earth with amorphous manganese oxide and its adsorption characteristics for lead ions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Song; Li, Duanyang; Su, Fei; Ren, Yuping; Qin, Gaowu, E-mail: lis@atm.neu.edu.cn

    2014-10-30

    Graphical abstract: - Highlights: • A uniform MnO{sub 2} layer was anchored onto diatomite surface. • Kinetics and isotherms over MnO{sub 2} modified diatomite were studied. • The Pb(II) adsorption is based on ion-exchange mechanism. - Abstract: A novel method to produce composite sorbent material compromising porous diatomaceous earth (DE) and surface functionalized amorphous MnO{sub 2} is reported. Via a simple in situ redox reaction over the carbonized DE powders, a uniform layer of amorphous MnO{sub 2} was anchored onto the DE surface. The hybrid adsorbent was characterized by X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. The batch method has been employed to investigate the effects of surface coating on adsorption performance of DE. According to the equilibrium studies, the adsorption capacity of DE for adsorbing lead ions after MnO{sub 2} modification increased more than six times. And the adsorption of Pb{sup 2+} on the MnO{sub 2} surface is based on ion-exchange mechanism. The developed strategy presents a novel opportunity to prepare composite adsorbent materials by integrating nanocrystals with porous matrix.

  17. Surface modification and fatigue behavior of nitinol for load bearing implants

    Science.gov (United States)

    Bernard, Sheldon A.

    Musculoskeletal disorders are recognized amongst the most significant human health problems that exist today. Even though considerable research and development has gone towards understanding musculoskeletal disorders, there is still lack of bone replacement materials that are appropriate for restoring lost structures and functions, particularly for load-bearing applications. Many materials on the market today, such as titanium and stainless steel, suffer from significantly higher modulus than natural bone and low bioactivity leading to stress shielding and implant loosening over longer time use. Nitinol (NiTi) is an equiatomic intermetallic compound of nickel and titanium whose unique biomechanical and biological properties contributed to its increasing use as a biomaterial. An innovative method for creating dense and porous net shape NiTi alloy parts has been developed to improve biological properties while maintaining comparable or better mechanical properties than commercial materials that are currently in use. Laser engineered net shaping (LENS(TM)) and surface electrochemistry modification was used to create dense/porous samples and micro textured surfaces on NiTi parts, respectively. Porous implants are known to promote cell adhesion and have a low elastic modulus, a combination that can significantly increase the life of an implant. However, porosity can significantly reduce the fatigue life of an implant, and very little work has been reported on the fatigue behavior of bulk porous metals, specifically on porous nitinol alloy. High-cycle rotating bending and compression-compression fatigue behavior of porous NiTi fabricated using LENS(TM) were studied. In cyclic compression loading, plastic strain increased with increasing porosity and it was evident that maximum strain was achieved during the first 50000 cycles and remained constant throughout the remaining loading. No failures were observed due to loading up to 150% of the yield strength. When subjected

  18. Nanocapillary Atmospheric Pressure Plasma Jet: A Tool for Ultrafine Maskless Surface Modification at Atmospheric Pressure.

    Science.gov (United States)

    Motrescu, Iuliana; Nagatsu, Masaaki

    2016-05-18

    With respect to microsized surface functionalization techniques we proposed the use of a maskless, versatile, simple tool, represented by a nano- or microcapillary atmospheric pressure plasma jet for producing microsized controlled etching, chemical vapor deposition, and chemical modification patterns on polymeric surfaces. In this work we show the possibility of size-controlled surface amination, and we discuss it as a function of different processing parameters. Moreover, we prove the successful connection of labeled sugar chains on the functionalized microscale patterns, indicating the possibility to use ultrafine capillary atmospheric pressure plasma jets as versatile tools for biosensing, tissue engineering, and related biomedical applications.

  19. Surface modification of bisphenol A polycarbonate material by ultraviolet Nd:YVO4 laser high-speed microprocessing technology

    International Nuclear Information System (INIS)

    Liu, Jianguo; Wang, Suhuan; Lv, Ming; Zeng, Xiaoyan

    2014-01-01

    In this paper, a low-cost and high-efficiency microprocessing modification technology for the surface of bisphenol A polycarbonate (BAPC) material was achieved (in particular, from hydrophilicity to hydrophobicity) at high laser scanning speeds (600–1000 mm s  − 1 ) and using an all-solid state, Q-switched, high-average power and nanosecond pulse Nd:YVO 4 laser (355 nm wavelength). During the modification, it was found that the laser fluence and pulse width were the two main parameters affecting the modification effect. Moreover, the modification had a significant effect on the water contact angle, wetting behavior, microstructure, average roughness and chemical composition of the surface. When the laser fluences applied were low (i.e., less than the so-called critical fluence of the UV laser modification of the BAPC material), the water contact angle was found to be a little less than the original, the hydrophilicity was slightly improved, the relative content of the oxygen-containing groups (e.g. O–C and COO  −  ) increased, the microstructure and average roughness only had a very slight change, and the wetting behavior complied with the Wenzel regime. On the other hand, when the laser fluences applied were high, the water contact angle significantly increased, the hydrophilicity markedly decreased and the relative content of the oxygen-containing groups also increased. Here, a porous microstructure with periodical v-type grooves was generated and the average roughness had an obvious increase. In this case, the wetting behavior could be explained by the Cassie-Baxter regime, i.e., the microstructure and average roughness change played a deciding role. The reason for this might be that different laser parameters result in different material deformation and removal processes, thereby resulting in different surface chemical compositions, microstructures, roughnesses and wetting properties. (paper)

  20. Rotary bending fatigue properties of Inconel 718 alloys by ultrasonic nanocrystal surface modification technique

    Directory of Open Access Journals (Sweden)

    Jun-Hyong Kim

    2015-08-01

    Full Text Available This study investigates the influence of ultrasonic nanocrystal surface modification (UNSM technique on fatigue properties of SAE AMS 5662 (solution treatment of Inconel 718 alloys. The fatigue properties of the specimens were investigated using a rotary bending fatigue tester. Results revealed that the UNSM-treated specimens showed longer fatigue life in comparison with those of the untreated specimens. The improvement in fatigue life of the UNSM-treated specimens is attributed mainly to the induced compressive residual stress, increased hardness, reduced roughness and refined grains at the top surface. Fractured surfaces were analysed using a scanning electron microscopy (SEM in order to give insight into the effectiveness of UNSM technique on fracture mechanisms and fatigue life.

  1. Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Abednejad, Atiye Sadat, E-mail: atiyeabednejad@gmail.com [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Research Center for New Technologies in Life Science Engineering, University of Tehran, P.O. Box 63894-14179, Tehran (Iran, Islamic Republic of); Ghaee, Azadeh [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of)

    2014-09-01

    Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H{sub 2} and O{sub 2} plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H{sub 2} and O{sub 2} plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion.

  2. Photo-induced surface modification to improve the performance of lead sulfide quantum dot solar cell.

    Science.gov (United States)

    Tulsani, Srikanth Reddy; Rath, Arup Kumar

    2018-07-15

    The solution-processed quantum dot (QD) solar cell technology has seen significant advancements in recent past to emerge as a potential contender for the next generation photovoltaic technology. In the development of high performance QD solar cell, the surface ligand chemistry has played the important role in controlling the doping type and doping density of QD solids. For instance, lead sulfide (PbS) QDs which is at the forefront of QD solar cell technology, can be made n-type or p-type respectively by using iodine or thiol as the surfactant. The advancements in surface ligand chemistry enable the formation of p-n homojunction of PbS QDs layers to attain high solar cell performances. It is shown here, however, that poor Fermi level alignment of thiol passivated p-type PbS QD hole transport layer with the n-type PbS QD light absorbing layer has rendered the photovoltaic devices from realizing their full potential. Here we develop a control surface oxidation technique using facile ultraviolet ozone treatment to increase the p-doping density in a controlled fashion for the thiol passivated PbS QD layer. This subtle surface modification tunes the Fermi energy level of the hole transport layer to deeper values to facilitate the carrier extraction and voltage generation in photovoltaic devices. In photovoltaic devices, the ultraviolet ozone treatment resulted in the average gain of 18% in the power conversion efficiency with the highest recorded efficiency of 8.98%. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Material surface modification for first wall protection

    International Nuclear Information System (INIS)

    Davis, M.J.

    1979-01-01

    The elements and strategy of a program to develop low Z surfaces for tokamak reactors is described. The development of low Z coated limiters is selected as an interim goal. Candidate materials were selected from the elements: Be, B, Al, Ti, V, C, O, N and their compounds. The effect of low energy erosion on surface morphology is shown for Be, TiC and VBe 12 . The tradeoffs in coating design are described. Stress analysis results for TiB 2 coated POCO graphite limiters for ORNL's ISX-B tokamak are given

  4. Preparation of MgO with High Surface Area, and Modification of Its Pore Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Moon Hee; Park, Dong Gon [Sookmyung Women' s University, Seoul (Korea, Republic of)

    2003-10-15

    Thermal decomposition of hydrated surface layer of Mg(OH){sub 2} at 500 .deg. C in vacuum turned non-porous MgO into porous one with high surface area of around 270 m{sup 2}/g. Most of its surface area, 74 %, was from micropores, and rest of it was from mesopores in wedge-shaped slits, exhibiting bimodal size distribution centered around 30 and 90 A. Rehydration followed by subsequent dehydration at 300 .deg. C in dynamic vacuum further raised the surface area to 340 m{sup 2}/g. Fraction of microporous surface area was increased to 93%, and the shape of the mesopores was modified into parallel slits with a specific dimension of 32 A. Application of Fe{sub 2}O{sub 3} over MgO via iron complex formation did not alter the pore characteristics of MgO core, except slightly increased pore dimension. Over the course of the modification, Fe{sub 2}O{sub 3} stayed on the surface possibly via spill-over reaction.

  5. Surface modification of poly(tetrafluoroethylene) films by low energy Ar+ ion-beam activation and UV-induced graft copolymerization

    International Nuclear Information System (INIS)

    Zhang Yan; Huan, A.C.H.; Tan, K.L.; Kang, E.T.

    2000-01-01

    Surface modification of poly(tetrafluoroethylene) (PTFE) films by Ar + ion-beam irradiation with varying ion energy and ion dose was carried out. The changes in surface composition of the irradiated PTFE films were characterized, both in situ and after exposure to air, by X-ray photoelectron spectroscopy (XPS). The possible mechanisms of chemical reaction induced by the incident ion beam on the surface of PTFE film included defluorination, chain scission and cross-linking, as indicated by the presence of the characteristic peak components associated with the - - -CF 3 , - - -CF, and C(CF 2 ) 4 species in the C 1s core-level spectra, the decrease in surface [F]/[C] ratio, and the increase in surface micro-hardness of the Ar + ion-beam-treated PTFE films. Furthermore, the free radicals generated by the ion-beam could react with oxygen in the air to give rise to oxidized carbon species, such as the peroxides, on the PTFE surface. Thus, after exposure to air, the Ar + ion-beam-pretreated PTFE films were susceptible to further surface modification by UV-induced graft copolymerization with a vinyl monomer, such as acrylamide (AAm). The graft concentrations were deduced from the XPS-derived surface stoichiometries. The Ar + ion energy and the ion dose affected not only the surface composition of the treated films but also the graft copolymerization efficiency of the corresponding pretreated films

  6. Study on surface modification of polymer films by using atmospheric plasma jet source

    International Nuclear Information System (INIS)

    Takemura, Yuichiro; Hara, Tamio; Yamaguchi, Naohiro

    2008-01-01

    Reactive gas plasma treatments of poly(ethylene terephthalate) (PET) and polyimide (Kapton) have been performed using an atmospheric plasmas jet source. Characteristics of surface modification have been examined by changing the distance between the plasma jet source and the treated sample, and by changing the working gas spaces. Simultaneously, each plasma jet source has been investigated by space-resolving spectroscopy in the UV/visible region. Polymer surfaces have been analyzed by X-ray photoelectron spectroscopy (XPS). A marked improvement in the hydrophilicity of the polymer surfaces has been made by using N 2 or O 2 plasma jet source with a very short exposure time of about 0.01 s, whereas the less improvement has been obtained using on air plasma jet source because of NO x compound production. Changes in the chemical states of C of the polymer surfaces have been observed in XPS spectra after N 2 plasma jet spraying. (author)

  7. Surface modification of upconverting nanoparticles by layer-by-layer assembled polyelectrolytes and metal ions.

    Science.gov (United States)

    Palo, Emilia; Salomäki, Mikko; Lastusaari, Mika

    2017-12-15

    Modificating and protecting the upconversion luminescence nanoparticles is important for their potential in various applications. In this work we demonstrate successful coating of the nanoparticles by a simple layer-by-layer method using negatively charged polyelectrolytes and neodymium ions. The layer fabrication conditions such as number of the bilayers, solution concentrations and selected polyelectrolytes were studied to find the most suitable conditions for the process. The bilayers were characterized and the presence of the desired components was studied and confirmed by various methods. In addition, the upconversion luminescence of the bilayered nanoparticles was studied to see the effect of the surface modification on the overall intensity. It was observed that with selected deposition concentrations the bilayer successfully shielded the particle resulting in stronger upconversion luminescence. The layer-by-layer method offers multiple possibilities to control the bilayer growth even further and thus gives promises that the use of upconverting nanoparticles in applications could become even easier with less modification steps in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. X-ray photoelectron spectroscopic depth profilometry of nitrogen implanted in materials for modification of their surface properties

    International Nuclear Information System (INIS)

    Sarkissian, A.H.; Paynter, R.; Stansfield, B.L.

    1996-01-01

    The modification of the surface properties of materials has a wide range of industrial applications. For example, the authors change the electrical characteristics of semiconductors, improve surface hardness, decrease friction, increase resistance to corrosion, improve adhesion, etc. Nitriding is one of the most common processes used in industry for surface treatment. Nitrogen ion implantation is one technique often used to achieve this goal. Ion implantation offers the power to control the deposition profile, and can be achieved by either conventional ion beam implantation or plasma assisted ion implantation. They have used the technique of plasma assisted ion implantation to implant nitrogen in several materials, including titanium, silicon and stainless steel. The plasma source is a surface ECR source developed at INRS-Energie et Materiaux. The depth profile of the implanted ions has been measured by X-ray photoelectron spectroscopy. They have also conducted simulations using the TRIM-95 code to predict the depth profile of the implanted ions. Comparisons of the measured results with those from simulations are used to deduce information regarding the plasma composition and the collisional effects in the plasma. A fast responding, current and voltage measuring circuit with fiber optic links is being developed, which allows more accurate quantitative measurements. Further experiments to study the characteristics of the plasma, and their effects on the characteristics of the implanted surfaces are in progress, and the results are presented at this meeting

  9. Surface modification and micromechanical properties of jute fiber mat reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available A new treating method using sodium hydroxide (NaOH and Maleic anhydride-grafted polypropylene (MPP emulsion was introduced to treat jute fiber mat in order to enhance the performance of jute/polypropylene (PP composite prepared by film stacking method. The surface modifications of jute fiber mat have been found to be very effective in improving the fiber-matrix adhesion. It was shown that treatments changed not only the surface topography but also the distribution of diameter and strength for the jute fibers, which was analyzed by using a two-parameter Weibull distribution model. Consequently, the interfacial shear strength, flexural and tensile strength of the composites all increased, but the impact strength decreased slightly. These results have demonstrated a new approach to use natural materials to enhance the mechanical performances of composites.

  10. Dual brush process for selective surface modification in graphoepitaxy directed self-assembly

    Science.gov (United States)

    Doise, Jan; Chan, Boon Teik; Hori, Masafumi; Gronheid, Roel

    2017-07-01

    Graphoepitaxy directed self-assembly is a potential low-cost solution for patterning via layers with pitches beyond the reach of a single optical lithographic exposure. In this process, selective control of the interfacial energy at the bottom and sidewall of the template is an important but challenging exercise. A dual brush process is implemented, in which two brushes with distinct end-groups are consecutively grafted to the prepattern to achieve fully independent modification of the bottom and sidewall surface of the template. A comprehensive study of hole pattern quality shows that using a dual brush process leads to a substantial improvement in terms of positional and dimensional variability across the process window. These findings will be useful to others who wish to manipulate polymer-surface interactions in directed self-assembly flows.

  11. Surface Modification of AISI 440B Stainless Steel and its Influence on Surgical Drill Bits Performance

    Directory of Open Access Journals (Sweden)

    Łępicka M.

    2016-09-01

    Full Text Available The development of modern invasive surgery is highly dependent on the performance of surgical instruments, understood as long-term efficiency arising from high resistance to wear and corrosion. In order to maintain sufficient reliability, surgical cutting instruments are often made of martensitic stainless steels. Nevertheless, the use of ferrous alloys in medical applications is still a concern due to their questionable corrosion and wear resistance. To extend their biocompatibility, improve stability in variable environmental conditions, improve ease of handling, and maximize their performance, diffusion layers and coatings are applied to the surface. The aim of this work was to evaluate the effect of TiN and diamond-like carbon (DLC surface modification on the performance of surgical drill bits, that is, wear and corrosion resistance, measured in model and field tests. Based on the findings presented, DLC layers can be recommended as anti-wear and anti-corrosion coatings for surgical drill bits.

  12. Surface modification of polyethylene by plasma; Modificacion superficial de polietileno por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Colin O, E

    2003-07-01

    The products made of polyethylene (PE) go from construction materials, electric insulating until packing material. The films for bags and pack occupy 83.6% of the distribution of the market of PE approximately. The enormous quantity of PE that is generated by its indiscriminate use brings as consequence a deterioration to the atmosphere, due to the long life that they present as waste. This work is a study on the modification of low density polyethylene films. In this type of thin materials, the changes in the surface meet with largely on the conformation of the rest of the material. To induce changes that modify the surface of PE, plasmas were used with reactive atmospheres of air, oxygen and nitrogen. The experimentation that was carries out went to introduce the PE to a cylindrical reactor where it was generated the plasma of air, oxygen and nitrogen to different times of exposure. After having carried out the exposure to the plasma, it was found that in the polyethylene it modifies their morphology, crystallinity, hydrophobicity, composition and electric conductivity. The analytical techniques that were used to characterize later to the polyethylene of being in contact with the plasma were: X-ray diffraction, Scanning Electron Microscopy, Infrared spectroscopy, Electric conductivity, Angle of contact and finally Thermal Gravimetric Analysis. The content of this work it is presented in five chapters: In the chapter 1 there are presented some general concepts of plasma and of the one polymer in study PE. In the chapter 2 it is made a general revision on modification of surfaces, as well as the properties that were modified in polymeric materials that were exposed to plasma in previous works. In the chapter 3 the experimental part and the conditions used are described in the modification of the PE. Also in this chapter a brief description it is made of the used characterization techniques. The results and discussion are presented in the chapter 4. These results

  13. Effect of Surface Modification of Palygorskite on the Properties of Polypropylene/Polypropylene-g-Maleic Anhydride/Palygorskite Nanocomposites

    Directory of Open Access Journals (Sweden)

    David Cisneros-Rosado

    2017-01-01

    Full Text Available The effect of surface modification of palygorskite (Pal on filler dispersion and on the mechanical and thermal properties of polypropylene (PP/polypropylene grafted maleic anhydride (PP-g-MAH/palygorskite (Pal nanocomposites was evaluated. A natural Pal mineral was purified and individually surface modified with hexadecyl tributyl phosphonium bromide and (3-Aminopropyltrimethoxysilane; the pristine and modified Pals were melt-compounded with PP to produce nanocomposites using PP-g-MAH as compatibilizer. The grafting of Pal surface was verified by FT-IR and the change in surface hydrophilicity was estimated by the contact angle of sessile drops of ethylene glycol on Pal tablets. The extent of Pal dispersion and the degree of improvement in both the mechanical and thermal properties were related to the surface treatment of Pal. Modified Pals were better dispersed during melt processing and improved Young’s modulus and strength; however, maximum deformation tended to decrease. The thermal stability of PP/PP-g-MAH/Pal nanocomposites was considerably improved with the content of modified Pals. The degree of crystallinity increased with Pal content, regardless of the surface modification. Surfactant modified Pal exhibited better results in comparison with silane Pal; it is possible that longer alkyl chains from surfactant molecules promoted interactions with polymer chains, thereby improving nanofiller dispersion and enhancing the properties.

  14. Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka

    2016-01-01

    Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

  15. Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications.

    Science.gov (United States)

    Agarwal, Sankalp; Curtin, James; Duffy, Brendan; Jaiswal, Swarna

    2016-11-01

    Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Inner surface modification of a tube by magnetic glow-arc plasma source ion implantation

    International Nuclear Information System (INIS)

    Zhang Guling; Chinese Academy of Sciences, Beijing; Wang Jiuli; Feng Wenran; Chen Guangliang; Gu Weichao; Niu Erwu; Fan Songhua; Liu Chizi; Yang Size; Wu Xingfang

    2006-01-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved. (authors)

  17. Inner Surface Modification of a Tube by Magnetic Glow-Arc Plasma Source Ion Implantation

    Science.gov (United States)

    Zhang, Gu-Ling; Wang, Jiu-Li; Wu, Xing-Fang; Feng, Wen-Ran; Chen, Guang-Liang; Gu, Wei-Chao; Niu, Er-Wu; Fan, Song-Hua; Liu, Chi-Zi; Yang, Si-Ze

    2006-05-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.

  18. Improving the antimicrobial properties of titanium condenser material by surface modification using nanotechnology

    International Nuclear Information System (INIS)

    George, Rani P.; Dash, S.; Krishnan, R.; Kamruddin, M.; Kalavathi, S.; Tyagi, A.K.; Manoharan, N.; Dayal, R.K.; Vishwakarma, Vinita; Theresa, Josephine

    2008-01-01

    Biofouling is one of the major problems faced by condenser materials of power plants using seawater for cooling. Fouling control strategies in condensers include a combination of mechanical and chemical treatments like sponge ball cleaning, back washing and chlorination. In general, numerous studies have shown that no routine treatment regime can successfully keep the condenser tube clean over a period extending to years. Surface properties of the substratum influence initial adhesion and growth of bacterial cells on materials, modification of the surface for mitigating microbial attachment is the need of the hour. Metal nanoparticles are known to exhibit enhanced physical and chemical properties when compared to their bulk counter parts because of their high surface to volume ratios. Metals like copper are very toxic to microorganisms and effectively kill most of the microbes by blocking the respiratory enzyme. Copper alloys with their excellent resistance to biofouling are used extensively for marine applications. However, they are prone to localized corrosion initiation and consequently are getting replaced by extremely corrosion resistant titanium. Still, the inertness and biocompatibility of titanium makes it very susceptible to biofouling. Hence, this study attempts to use nano technology methods of surface modification of titanium using thin film of copper and also multilayers and bilayers of copper and nickel. This is aimed at improving the antimicrobial properties of this condenser pipe material. These nano structured thin films have been grown on titanium substrate using pulsed DC magnetron-sputtering and pulsed laser deposition. The thin films were characterized using Atomic Force Microscopy (AFM), Glancing Incidence X-ray Diffraction (GIXRD) and scanning electron microscopy (SEM with EDAX analysis). Antimicrobial properties were evaluated by exposure studies in seawater and bacterial cultures and by post exposure analysis using culture and

  19. Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu, E-mail: sde@che.iitkgp.ernet.in

    2015-12-31

    Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

  20. Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

    International Nuclear Information System (INIS)

    Pal, Dipankar; Neogi, Sudarsan; De, Sirshendu

    2015-01-01

    Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70 days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200 kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity. - Highlights: • Surface modification of polyacrylonitrile co-polymer membranes by pulsed direct current nitrogen plasma • Hydrophilic functional groups incorporated on the membrane surface • Significant enhancement of the permeability and wettability of the membranes • Water contact angle increased with storage time and finally stabilized.

  1. Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation

    Directory of Open Access Journals (Sweden)

    Wennerberg Ann

    2011-03-01

    Full Text Available Abstract Background The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown. Methods We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy. Results Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm. Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth. Conclusions Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm

  2. A Chemical-Adsorption Strategy to Enhance the Reaction Kinetics of Lithium-Rich Layered Cathodes via Double-Shell Surface Modification.

    Science.gov (United States)

    Guo, Lichao; Li, Jiajun; Cao, Tingting; Wang, Huayu; Zhao, Naiqin; He, Fang; Shi, Chunsheng; He, Chunnian; Liu, Enzuo

    2016-09-21

    Sluggish surface reaction kinetics hinders the power density of Li-ion battery. Thus, various surface modification techniques have been applied to enhance the electronic/ionic transfer kinetics. However, it is challenging to obtain a continuous and uniform surface modification layer on the prime particles with structure integration at the interface. Instead of classic physical-adsorption/deposition techniques, we propose a novel chemical-adsorption strategy to synthesize double-shell modified lithium-rich layered cathodes with enhanced mass transfer kinetics. On the basis of experimental measurement and first-principles calculation, MoO2S2 ions are proved to joint the layered phase via chemical bonding. Specifically, the Mo-O or Mo-S bonds can flexibly rotate to bond with the cations in the layered phase, leading to the good compatibility between the thiomolybdate adsorption layer and layered cathode. Followed by annealing treatment, the lithium-excess-spinel inner shell forms under the thiomolybdate adsorption layer and functions as favorable pathways for lithium and electron. Meanwhile, the nanothick MoO3-x(SO4)x outer shell protects the transition metal from dissolution and restrains electrolyte decomposition. The double-shell modified sample delivers an enhanced discharge capacity almost twice as much as that of the unmodified one at 1 A g(-1) after 100 cycles, demonstrating the superiority of the surface modification based on chemical adsorption.

  3. Diagnostics of microwave assisted electron cyclotron resonance plasma source for surface modification of nylon 6

    Science.gov (United States)

    More, Supriya E.; Das, Partha Sarathi; Bansode, Avinash; Dhamale, Gayatri; Ghorui, S.; Bhoraskar, S. V.; Sahasrabudhe, S. N.; Mathe, Vikas L.

    2018-01-01

    Looking at the increasing scope of plasma processing of materials surface, here we present the development and diagnostics of a microwave assisted Electron Cyclotron Resonance (ECR) plasma system suitable for surface modification of polymers. Prior to the surface-treatment, a detailed diagnostic mapping of the plasma parameters throughout the reactor chamber was carried out by using single and double Langmuir probe measurements in Ar plasma. Conventional analysis of I-V curves as well as the elucidation form of the Electron Energy Distribution Function (EEDF) has become the source of calibration of plasma parameters in the reaction chamber. The high energy tail in the EEDF of electron temperature is seen to extend beyond 60 eV, at much larger distances from the ECR zone. This proves the suitability of the rector for plasma processing, since the electron energy is much beyond the threshold energy of bond breaking in most of the polymers. Nylon 6 is used as a representative candidate for surface processing in the presence of Ar, H2 + N2, and O2 plasma, treated at different locations inside the plasma chamber. In a typical case, the work of adhesion is seen to almost get doubled when treated with oxygen plasma. Morphology of the plasma treated surface and its hydrophilicity are discussed in view of the variation in electron density and electron temperature at these locations. Nano-protrusions arising from plasma treatment are set to be responsible for the hydrophobicity. Chemical sputtering and physical sputtering are seen to influence the surface morphology on account of sufficient electron energies and increased plasma potential.

  4. Surface modification of carbon fibers and its effect on the fiber–matrix interaction of UHMWPE based composites

    International Nuclear Information System (INIS)

    Chukov, D.I.; Stepashkin, A.A.; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-01-01

    Highlights: • Both chemical and thermal treatments of UKN 5000 carbon fibers allow one to obtain well-developed surface. • The changes of structure and properties of VMN-4 fibers after both thermal and chemical oxidation are insignificant due to more perfect initial structure of these fibers. • The oxidative treatment of carbon fibers allows one to improve the interfacial interaction in the UHMWPE-based composites. • The oxidative treatment of the fibers allows one to a triple increase of Young’s modulus of the modified fibers reinforced UHMWPE composites. -- Abstract: The PAN-based carbon fibers (CF) were subjected to thermal and chemical oxidation under various conditions. The variation in the surface morphology of carbon fibers after surface treatment was analyzed by scanning electron microscopy (SEM). It was found that the tensile strength of carbon fibers changed after surface modification. The interaction between the fibers and the matrix OF ultra-high molecular weight polyethylene (UHMWPE) was characterized by the Young modulus of produced composites. It was shown that the Young modulus of composites reinforced with modified carbon fibers was significantly higher than that of composites reinforced with non-modified fibers

  5. Surface modification of nanodiamond through metal free atom transfer radical polymerization

    Science.gov (United States)

    Zeng, Guangjian; Liu, Meiying; Shi, Kexin; Heng, Chunning; Mao, Liucheng; Wan, Qing; Huang, Hongye; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2016-12-01

    Surface modification of nanodiamond (ND) with poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] has been achieved by using metal free surface initiated atom transfer radical polymerization (SI-ATRP). The ATRP initiator was first immobilized on the surface of ND through direct esterification reaction between hydroxyl group of ND and 2-bromoisobutyryl bromide. The initiator could be employed to obtain ND-poly(MPC) nanocomposites through SI-ATRP using an organic catalyst. The final functional materials were characterized by 1H nuclear magnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermo gravimetric analysis in detailed. All of these characterization results demonstrated that ND-poly(MPC) have been successfully obtained via metal free photo-initiated SI-ATRP. The ND-poly(MPC) nanocomposites shown enhanced dispersibility in various solvents as well as excellent biocompatibility. As compared with traditional ATRP, the metal free ATRP is rather simple and effective. More importantly, this preparation method avoided the negative influence of metal catalysts. Therefore, the method described in this work should be a promising strategy for fabrication of polymeric nanocomposites with great potential for different applications especially in biomedical fields.

  6. Experimental investigation of the material surface modification in microsecond plasma opening switch

    Energy Technology Data Exchange (ETDEWEB)

    Bystritskij, V; Grigor` ev, S; Kharlov, A; Sinebryukhov, A [Russian Academy of Sciences, Tomsk (Russian Federation). Institute of Electrophysics; Burkov, P [Russian Academy of Scinces, Tomsk (Russian Federation). Institute of Strength Physics and Materials Control; Grigorev, V; Koval, T [Institute of Nuclear Physics, Tomsk (Russian Federation)

    1997-12-31

    The paper is devoted to the investigations of the material surface modification by high power ion beam generated in microsecond plasma opening switch (MPOS). Various types of steels were investigated: stainless steel 17-4PH, carbon steel C1020, pure iron. For all these materials, the optimal regimes for irradiation were defined. A significant increase in microhardness (1.5 to 2-fold) was obtained for these materials. Numerical calculations and theoretical estimations of the ion beam-matter interaction were also performed. The advantages and problems of this approach are discussed. (author). 8 figs., 3 refs.

  7. A Simple Surface Modification of NiO Cathode with TiO2 Nano-Particles for Molten Carbonate Fuel Cells (MCFCs)

    International Nuclear Information System (INIS)

    Choi, Hee Seon; Kim, Keon; Yi, Cheolwoo

    2014-01-01

    The TiO 2 -modified Ni powders, prepared by the simple method (ball-milling and subsequent annealing) without resorting to any complex coating process, eventually form nickel titanate passive layer at high temperature. It as good corrosion resistance in molten carbonates media and higher electrical conductivity at high temperature. In addition, the modified cathode increases the degree of lithiation during the operation of MCFC. These positive effects provide a decrease in the internal resistance and improve the cell performance. Results obtained from this study can be applied to develop the surface modification of cathode materials and the performance of molten carbonate fuel cells. Molten carbonate fuel cells (MCFCs) are efficient energy conversion devices to convert chemical energy into electrical energy through the electrochemical reaction. Because of a lot of advantages of MCFC operated at high temperature, many researchers have been trying to apply it to large-scaled power generations, marine boats, and so on. Among various cathode materials, nickel oxide, NiO, is the most widely used cathode for MCFCs due to its stability and high electrical conductivity, but the degradation of cathode material, so-called NiO dissolution, prevents a long-term operation of MCFC. In order to overcome the drawback, numerous studies have been performed. One of the most useful ways to enhance the surface property and maintain the bulk property of the host materials is the surface modification. The most common modification method is coating and these coating procedures which need some complicated steps with the use of organic materials, but it restricts the large-scale fabrication. In this study, to improve the electrochemical performance, we have prepared an alternative MCFC cathode material, TiO 2 -modified NiO, by simple method without resorting to any complex coating process. Results obtained in this study can provide an effective way to mass-produce the cathode materials

  8. Modification and characterization of the AISI 410 martensitic stainless steels surface

    International Nuclear Information System (INIS)

    Bincoleto, A.V.L.; Nascente, P.A.P.

    2010-01-01

    Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

  9. Preparation and studies on surface modifications of calcium-silico-phosphate ferrimagnetic glass-ceramics in simulated body fluid

    International Nuclear Information System (INIS)

    Sharma, K.; Dixit, A.; Singh, Sher; Jagannath,; Bhattacharya, S.; Prajapat, C.L.; Sharma, P.K.; Yusuf, S.M.; Tyagi, A.K.; Kothiyal, G.P.

    2009-01-01

    The structure and magnetic behaviour of 34SiO 2 -(45 - x) CaO-16P 2 O 5 -4.5 MgO-0.5 CaF 2 - x Fe 2 O 3 (where x = 5, 10, 15, 20 wt.%) glasses have been investigated. Ferrimagnetic glass-ceramics are prepared by melt quench followed by controlled crystallization. The surface modification and dissolution behaviour of these glass-ceramics in simulated body fluid (SBF) have also been studied. Phase formation and magnetic behaviour have been studied using XRD and SQUID magnetometer. The room temperature Moessbauer study has been done to monitor the local environment around Fe cations and valence state of Fe ions. X-ray photoelectron spectroscopy (XPS) was used to study the surface modification in glass-ceramics when immersed in simulated body fluid. Formation of bioactive layer in SBF has been ascertained using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The SBF solutions were analyzed using an absorption spectrophotometer. The magnetic measurements indicated that all these glasses possess paramagnetic character and the [Fe 2+ /Fe 3+ ] ions ratio depends on the composition of glass and varied with Fe 2 O 3 concentration in glass matrix. In glass-ceramics saturation magnetization increases with increase in amount of Fe 2 O 3 . The nanostructure of hematite and magnetite is formed in the glass-ceramics with 15 and 20 wt.% Fe 2 O 3 , which is responsible for the magnetic property of these glass-ceramics. Introduction of Fe 2 O 3 induces several modifications at the glass-ceramics surface when immersed in SBF solution and thereby affecting the surface dissolution and the formation of the bioactive layer.

  10. Materials surface modification by plasma bombardment under simultaneous erosion and redeposition conditions

    International Nuclear Information System (INIS)

    Hirooka, Y.; Goebel, D.M.; Conn, R.W.

    1986-07-01

    The first in-depth investigation of surface modification of materials by continuous, high-flux argon plasma bombardment under simultaneous erosion and redeposition conditions have been carried out for copper and 304 stainless steel using the PISCES facility. The plasma bombardment conditions are: incident ion flux range from 10 17 to 10 19 ions sec -1 cm -2 , total ion fluence is controlled between 10 19 and 10 22 ions cm -2 , electron temperature range from 5 to 15 eV, and plasma density range from 10 11 to 10 13 cm -3 . The incident ion energy is 100 eV. The sample temperature is between 300 and 700K. Under redeposition dominated conditions, the material erosion rate due to the plasma bombardment is significantly smaller (by a factor up to 10) than that can be expected from the classical ion beam sputtering yield data. It is found that surface morphologies of redeposited materials strongly depend on the plasma bombardment condition. The effect of impurities on surface morphology is elucidated in detail. First-order modelings are implemented to interpret the reduced erosion rate and the surface evolution. Also, fusion related surface properties of redeposited materials such as hydrogen reemission and plasma driven permeation have been characterized

  11. Controlling the surface photovoltage on WSe2 by surface chemical modification

    Science.gov (United States)

    Liu, Ro-Ya; Ozawa, Kenichi; Terashima, Naoya; Natsui, Yuto; Feng, Baojie; Ito, Suguru; Chen, Wei-Chuan; Cheng, Cheng-Maw; Yamamoto, Susumu; Kato, Hiroo; Chiang, Tai-Chang; Matsuda, Iwao

    2018-05-01

    The surface photovoltage (SPV) effect is key to the development of opto-electronic devices such as solar-cells and photo-detectors. For the prototypical transition metal dichalcogenide WSe2, core level and valence band photoemission measurements show that the surface band bending of pristine cleaved surfaces can be readily modified by adsorption with K (an electron donor) or C60 (an electron acceptor). Time-resolved pump-probe photoemission measurements reveal that the SPV for pristine cleaved surfaces is enhanced by K adsorption, but suppressed by C60 adsorption, and yet the SPV relaxation time is substantially shortened in both cases. Evidently, adsorbate-induced electronic states act as electron-hole recombination centers that shorten the carrier lifetime.

  12. Nanometer-size surface modification produced by single, low energy, highly charged ions

    International Nuclear Information System (INIS)

    Stockli, M.P.

    1994-01-01

    Atomically flat surfaces of insulators have been bombarded with low energy, highly charged ions to search for nanometer-size surface modifications. It is expected that the high electron deficiency of highly charged ions will capture and/or remove many of the insulator's localized electrons when impacting on an insulating surface. The resulting local electron deficiency is expected to locally disintegrate the insulator through a open-quotes Coulomb explosionclose quotes forming nanometer-size craters. Xe ions with charge states between 10+ and 45+ and kinetic energies between 0 and 10 keV/q were obtained from the KSU-CRYEBIS, a CRYogenic Electron Beam Ion Source and directed onto various insulating materials. Mica was favored as target material as atomically flat surfaces can be obtained reliably through cleaving. However, the authors observations with an atomic force microscope have shown that mica tends to defoliate locally rather than disintegrate, most likely due to the small binding forces between adjacent layers. So far the authors measurements indicate that each ion produces one blister if the charge state is sufficiently high. The blistering does not seem to depend very much on the kinetic energy of the ions

  13. Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

    Science.gov (United States)

    Nassisi, Vincenzo; Delle Side, Domenico; Turco, Vito; Martina, Luigi

    2018-01-01

    In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS) coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

  14. Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

    Directory of Open Access Journals (Sweden)

    Nassisi Vincenzo

    2018-01-01

    Full Text Available In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

  15. Electron beam deflection control system of a welding and surface modification installation

    Science.gov (United States)

    Koleva, E.; Dzharov, V.; Gerasimov, V.; Tsvetkov, K.; Mladenov, G.

    2018-03-01

    In the present work, we examined the patterns of the electron beam motion when controlling the transverse with respect to the axis of the beam homogeneous magnetic field created by the coils of the deflection system the electron gun. During electron beam processes, the beam motion is determined the process type (welding, surface modification, etc.), the technological mode, the design dimensions of the electron gun and the shape of the processed samples. The electron beam motion is defined by the cumulative action of two cosine-like control signals generated by a functional generator. The signal control is related to changing the amplitudes, frequencies and phases (phase differences) of the generated voltages. We realized the motion control by applying a graphical user interface developed by us and an Arduino Uno programmable microcontroller. The signals generated were calibrated using experimental data from the available functional generator. The free and precise motion on arbitrary trajectories determines the possible applications of an electron beam process to carrying out various scientific research tasks in material processing.

  16. Eco-friendly surface modification on polyester fabrics by esterase treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jindan; Cai, Guoqiang; Liu, Jinqiang; Ge, Huayun; Wang, Jiping, E-mail: jipingwanghz@gmail.com

    2014-03-01

    Graphical abstract: - Highlights: • We used a simple and easy way to measure the enzyme activity. • We studied the mechanism by characterizing the chemical changes in the surface of fabric. • We studied the advantages in surface wettability, fiber integrity and mechanical performance of cutinase treated fabrics. • Cutinase pretreated fibers exhibited much improved fabric wicking and better fiber integrity comparing to alkali treated ones. • Cutinase pretreatment technology promotes energy conservation and emission reduction. - Abstract: Currently, traditional alkali deweighting technology is widely used to improve the hydrophilicity of polyester fabrics. However, the wastewater and heavy chemicals in the effluent cause enormous damage to the environment. Esterase treatment, which is feasible in mild conditions with high selectivity, can provide a clean and efficient way for polyester modification. Under the optimum conditions, the polyester fabric hydrolysis process of esterase had a linear kinetics. X-ray photoelectron spectrometry (XPS) results showed that hydroxyl and carboxyl groups were produced only on the surface of modified fiber without changing the chemical composition of the bulk. These fibers exhibited much improved fabric wicking, as well as greatly improved oily stain removal performance. Compared to the harsh alkali hydrolysis, the enzyme treatment led to smaller weight loss and better fiber integrity. The esterase treatment technology is promising to produce higher-quality polyester textiles with an environmental friendly approach.

  17. MODIFICATION OF PAPERMAKING GRADE FILLERS: A BRIEF REVIEW

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2009-08-01

    Full Text Available The use of fillers in paper products can provide cost and energy savings, improved paper properties, increased productivities, and specifically desired paper functionalities. There are many problems associated with the use of fillers, such as unsuitability of calcium carbonate fillers in acid papermaking, negative effects of filler loading on paper strength, sizing, and retention, and tendencies of fillers to cause abrasion and dusting. In order to solve these problems and to make better use of fillers, many methods have been proposed, among which filler modification has been a hot topic. The available technologies of filler modification mainly include modification with inorganic substances, modification with natural polymers or their derivatives, modification with water-soluble synthetic polymers, modification with surfactants, modification with polymer latexes, hydrophobic modification, cationic modification, surface nano-structuring, physical modification by compressing, calcination or grinding, and modification for use in functional papers. The methods of filler modification can provide improved acid tolerant and optical properties of fillers, enhanced fiber-filler bonding, improved filler retention and filler sizabilities, alleviated filler abrasiveness, improved filler dispersability, and functionalization of filled papers. Filler modification has been an indispensable way to accelerate the development of high filler technology in papermaking, which is likely to create additional benefits to papermaking industry in the future.

  18. First-principles investigation of the electronic and Li-ion diffusion properties of LiFePO4 by sulfur surface modification

    International Nuclear Information System (INIS)

    Xu, Guigui; Zhong, Kehua; Zhang, Jian-Min; Huang, Zhigao

    2014-01-01

    We present a first-principles calculation for the electronic and Li-ion diffusion properties of the LiFePO 4 (010) surface modified by sulfur. The calculated formation energy indicates that the sulfur adsorption on the (010) surface of the LiFePO 4 is energetically favored. Sulfur is found to form Fe-S bond with iron. A much narrower band gap (0.67 eV) of the sulfur surface-modified LiFePO 4 [S-LiFePO 4 (010)] is obtained, indicating the better electronic conductive properties. By the nudged elastic band method, our calculations show that the activation energy of Li ions diffusion along the one-dimensional channel on the surface can be effectively reduced by sulfur surface modification. In addition, the surface diffusion coefficient of S-LiFePO 4 (010) is estimated to be about 10 −11 (cm 2 /s) at room temperature, which implies that sulfur modification will give rise to a higher Li ion carrier mobility and enhanced electrochemical performance

  19. Polyaniline on surface modification of diatomite: a novel way to obtain conducting diatomite fillers

    International Nuclear Information System (INIS)

    Li Xingwei; Bian Chaoqing; Chen Wei; He Jinbo; Wang Zhaoquen; Xu Ning; Xue Gi

    2003-01-01

    A conducting diatomite was obtained by polyaniline on surface modification of diatomite, and was characterized via Fourier-transform Raman spectra, UV-Vis absorption spectra, thermogravimetric analysis and scanning electron microscope, as well as conductivity. The results of spectroanalysis illustrate that polyaniline is not simply blended with diatomite. An interaction exists at the interface of diatomite and polyaniline, which may associate with hydrogen bond formed between the surface of diatomite with electronegativity and N-H bond in polyaniline macromolecule. The results of thermogravimetric analysis suggest that the conducting diatomite only contains 8% polyaniline by mass, but its conductivity has reached 2.8x10 -2 S cm -1 at 20 deg. C

  20. Surface modification of chitosan/PEO nanofibers by air dielectric barrier discharge plasma for acetylcholinesterase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Dorraki, Naghme, E-mail: n.dorraki@web.sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Safa, Nasrin Navab [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Jahanfar, Mehdi [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ghomi, Hamid [Laser and Plasma Research Institute, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of); Ranaei-Siadat, Seyed-Omid [Protein Research Center, Shahid Beheshti University, Evin 1983963113, Tehran (Iran, Islamic Republic of)

    2015-09-15

    Highlights: • We used an economical and effective method for surface modification. • Chitosan/PEO nanofibrous membranes were modified by air-DBD plasma. • The most NH{sub 3}{sup +} group was generated on the 6 min plasma modified membrane. • We immobilized acetylcholinesterase on the plasma modified and unmodified membranes. • More enzyme activity was detected on the modified membrane by plasma. - Abstract: There are different methods to modify polymer surfaces for biological applications. In this work we have introduced air-dielectric barrier discharge (DBD) plasma at atmospheric pressure as an economical and safe method for modifying the surface of electrospun chitosan/PEO (90/10) nanofibers for acetylcholinesterase (AChE) immobilization. According to the contact angle measurement results, the nanofibers become highly hydrophilic when they are exposed to the DBD plasma for 6 min in compared to unmodified membrane. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results reveal hydroxyl, C=O and NH{sub 3}{sup +} polar groups increment after 6 min plasma treatment. Contact angle measurements and ATR-FTIR results are confirmed by X-ray photoelectron spectroscopy (XPS). AChE at pH 7.4 carries a negative charge and after immobilization on the surface of plasma-treated nanofibrous membrane attracts the NH{sub 3}{sup +} group and more enzyme activity is detected on the plasma-modified nanofibers for 6 min in compared to unmodified nanofibers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are used for the surface topography and morphology characterization. The results have proved that air-DBD plasma is a suitable method for chitosan/PEO nanofibrous membrane modification as a biodegradable and functionalized substrate for enzyme immobilization.

  1. Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

    Science.gov (United States)

    Shearer, Jeffrey C.

    Functionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as --OH and --NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxC y and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2 O3 supported nanoparticles. Specifically, film composition was

  2. Nano-sized surface modifications induced by the impact of slow highly charged ions - A first review

    International Nuclear Information System (INIS)

    Aumayr, F.; El-Said, A.S.; Meissl, W.

    2008-01-01

    Irradiation of crystalline solid targets with swift heavy ions can lead to the formation of latent tracks in the solid and the creation of (mostly-hillock type) nanostructures on the surface. Recently similar surface modifications with nanometer dimensions have been demonstrated for the impact of individual, very slow but highly charged ions on various surfaces. We will review the current state of this new field of research. In particular we will discuss the circumstances and conditions under which nano-sized features (hillocks or craters) on different surfaces due to impact of slow highly charged ions can be produced. The use of slow highly charged ions instead of swift heavy ions might be of considerable interest for some practical applications

  3. Surface modification of chitin and chitosan with poly(3-hexylthiophene) via oxidative polymerization

    Science.gov (United States)

    Hai, Thien An Phung; Sugimoto, Ryuichi

    2018-03-01

    In the present work, the modification of biomaterials such as chitin and chitosan were successfully prepared by directly grafting poly(3-hexylthiophene) (P3HT) to their surfaces using simple oxidative polymerization with FeCl3. The thermal stability and crystallinity of grafted chitin and chitosan changed upon grafting with P3HT. The build-up of π-π* structure from the P3HT on the surface of chitin and chitosan resulted in the appearance of UV-vis absorption and fluorescence emission peaks in the range from 500 to 600 nm. Introducing P3HT to the surface of chitin and chitosan improved significantly the electrical property of chitin and chitosan with the increase in conductivity from 10-9 to 10-7 S/cm. Furthermore, the usual behavior of hydrophilic surface of chitin and chitosan that turned to hydrophobic with water contact angle of 97.7° and 107.0°, respectively in the presence of P3HT. The mechanism for graft reaction of P3HT to chitin and chitosan was also proposed and discussed.

  4. Silver nanoparticle-enriched diamond-like carbon implant modification as a mammalian cell compatible surface with antimicrobial properties

    Science.gov (United States)

    Gorzelanny, Christian; Kmeth, Ralf; Obermeier, Andreas; Bauer, Alexander T.; Halter, Natalia; Kümpel, Katharina; Schneider, Matthias F.; Wixforth, Achim; Gollwitzer, Hans; Burgkart, Rainer; Stritzker, Bernd; Schneider, Stefan W.

    2016-01-01

    The implant-bone interface is the scene of competition between microorganisms and distinct types of tissue cells. In the past, various strategies have been followed to support bony integration and to prevent bacterial implant-associated infections. In the present study we investigated the biological properties of diamond-like carbon (DLC) surfaces containing silver nanoparticles. DLC is a promising material for the modification of medical implants providing high mechanical and chemical stability and a high degree of biocompatibility. DLC surface modifications with varying silver concentrations were generated on medical-grade titanium discs, using plasma immersion ion implantation-induced densification of silver nanoparticle-containing polyvinylpyrrolidone polymer solutions. Immersion of implants in aqueous liquids resulted in a rapid silver release reducing the growth of surface-bound and planktonic Staphylococcus aureus and Staphylococcus epidermidis. Due to the fast and transient release of silver ions from the modified implants, the surfaces became biocompatible, ensuring growth of mammalian cells. Human endothelial cells retained their cellular differentiation as indicated by the intracellular formation of Weibel-Palade bodies and a high responsiveness towards histamine. Our findings indicate that the integration of silver nanoparticles into DLC prevents bacterial colonization due to a fast initial release of silver ions, facilitating the growth of silver susceptible mammalian cells subsequently. PMID:26955791

  5. Surface modifications on toughened, fine-grained, recrystallized tungsten with repetitive ELM-like pulsed plasma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Y., E-mail: ykikuchi@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Sakuma, I.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kurishita, H. [Institute for Materials Research, Tohoku University, Ibaraki 311-1313 (Japan)

    2015-08-15

    Surface modifications of toughened, fine-grained, recrystallized tungsten (TFGR W) materials with 1.1 wt.% TiC and 3.3 wt.% TaC dispersoids due to repetitive ELM-like pulsed (∼0.15 ms) helium plasma irradiation have been investigated by using a magnetized coaxial plasma gun. No surface cracking at the center part of the TFGR W samples exposed to 20 plasma pulses of ∼0.3 MJ m{sup −2} was observed. The suppression of surface crack formation due to the increase of the grain boundary strength by addition of TiC and TaC dispersoids was confirmed in comparison with a pure W material. On the other hand, surface cracks and small pits appeared at the edge part of the TFGR W sample after the pulsed plasma irradiation. Erosion of the TiC and TaC dispersoids due to the pulsed plasma irradiation could cause the small pits on the surface, resulting in the surface crack formation.

  6. Surface modifications on toughened, fine-grained, recrystallized tungsten with repetitive ELM-like pulsed plasma irradiation

    Science.gov (United States)

    Kikuchi, Y.; Sakuma, I.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.; Ueda, Y.; Kurishita, H.

    2015-08-01

    Surface modifications of toughened, fine-grained, recrystallized tungsten (TFGR W) materials with 1.1 wt.% TiC and 3.3 wt.% TaC dispersoids due to repetitive ELM-like pulsed (∼0.15 ms) helium plasma irradiation have been investigated by using a magnetized coaxial plasma gun. No surface cracking at the center part of the TFGR W samples exposed to 20 plasma pulses of ∼0.3 MJ m-2 was observed. The suppression of surface crack formation due to the increase of the grain boundary strength by addition of TiC and TaC dispersoids was confirmed in comparison with a pure W material. On the other hand, surface cracks and small pits appeared at the edge part of the TFGR W sample after the pulsed plasma irradiation. Erosion of the TiC and TaC dispersoids due to the pulsed plasma irradiation could cause the small pits on the surface, resulting in the surface crack formation.

  7. In situ modification of activated carbons developed from a native invasive wood on removal of trace toxic metals from wastewater.

    Science.gov (United States)

    de Celis, J; Amadeo, N E; Cukierman, A L

    2009-01-15

    Activated carbons were developed by phosphoric acid activation of sawdust from Prosopis ruscifolia wood, an indigenous invasive species of degraded lands, at moderate conditions (acid/precursor ratio=2, 450 degrees C, 0.5h). For in situ modification of their characteristics, either a self-generated atmosphere or flowing air was used. The activated carbons developed in the self-generated atmosphere showed higher BET surface area (2281m2/g) and total pore volume (1.7cm3/g) than those obtained under flowing air (1638m2/g and 1.3cm3/g). Conversely, the latter possessed a higher total amount of surface acidic/polar oxygen groups (2.2meq/g) than the former (1.5meq/g). To evaluate their metal sorption capability, adsorption isotherms of Cu(II) ion from model solutions were determined and properly described by the Langmuir model. Maximum sorption capacity (Xm) for the air-derived carbons (Xm=0.44mmol/g) almost duplicated the value for those obtained in the self-generated atmosphere (Xm=0.24mmol/g), pointing to a predominant effect of the surface functionalities on metal sequestering behaviour. The air-derived carbons also demonstrated a superior effectiveness in removing Cd(II) ions as determined from additional assays in equilibrium conditions. Accordingly, effective phosphoric acid-activated carbons from Prosopis wood for toxic metals removal from wastewater may be developed by in situ modification of their characteristics operating under flowing air.

  8. Surface modification induced by UV nanosecond Nd:YVO4 laser structuring on biometals

    Science.gov (United States)

    Fiorucci, M. Paula; López, Ana J.; Ramil, Alberto

    2014-08-01

    Laser surface texturing is a promising tool for improving metallic biomaterials performance in dental and orthopedic bone-replacing applications. Laser ablation modifies the topography of bulk material and might alter surface properties that govern the interactions with the surrounding tissue. This paper presents a preliminary evaluation of surface modifications in two biometals, stainless steel 316L and titanium alloy Ti6Al4V by UV nanosecond Nd:YVO4. Scanning electron microscopy of the surface textured by parallel micro-grooves reveals a thin layer of remelted material along the grooves topography. Furthermore, X-ray diffraction allowed us to appreciate a grain refinement of original crystal structure and consequently induced residual strain. Changes in the surface chemistry were determined by means of X-ray photoelectron spectroscopy; in this sense, generalized surface oxidation was observed and characterization of the oxides and other compounds such hydroxyl groups was reported. In case of titanium alloy, oxide layer mainly composed by TiO2 which is a highly biocompatible compound was identified. Furthermore, laser treatment produces an increase in oxide thickness that could improve the corrosion behavior of the metal. Otherwise, laser treatment led to the formation of secondary phases which might be detrimental to physical and biocompatibility properties of the material.

  9. Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

    Energy Technology Data Exchange (ETDEWEB)

    Mu Lijun, E-mail: l.j.mu@hotmail.com [School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Zhao Wenzhen [School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2009-05-30

    A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 {mu}g/cm{sup 2} was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.

  10. Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

    International Nuclear Information System (INIS)

    Mu Lijun; Zhao Wenzhen

    2009-01-01

    A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 μg/cm 2 was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.

  11. Surface modification of zinc oxide nanoparticle by PMAA and its dispersion in aqueous system

    Energy Technology Data Exchange (ETDEWEB)

    Tang Erjun [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang Hebei 050018 (China); Cheng Guoxiang [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)]. E-mail: gxcheng@tju.edu.cn; Ma Xiaolu [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Pang Xingshou [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhao Qiang [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2006-05-15

    Commercial zinc oxide nanoparticles were modified by polymethacrylic acid (PMAA) in aqueous system. The hydroxyl groups of nano-ZnO particle surface can interact with carboxyl groups (COO-) of PMAA and form poly(zinc methacrylate) complex on the surface of nano-ZnO. The formation of poly(zinc methacrylate) complex was testified by Fourier-transform infrared spectra (FT-IR). Thermogravimetric analysis (TGA) indicated that PMAA molecules were absorbed or anchored on the surface of nano-ZnO particle, which facilitated to hinder the aggregation of nano-ZnO particles. Through particle size analysis and transmission electron micrograph (TEM) observation, it was found that PMAA enhanced the dispersibility of nano-ZnO particles in water. The dispersion stabilization of modified ZnO nanoparticles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nanoparticles. The modification did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns.

  12. Surface modification of zinc oxide nanoparticle by PMAA and its dispersion in aqueous system

    Science.gov (United States)

    Tang, Erjun; Cheng, Guoxiang; Ma, Xiaolu; Pang, Xingshou; Zhao, Qiang

    2006-05-01

    Commercial zinc oxide nanoparticles were modified by polymethacrylic acid (PMAA) in aqueous system. The hydroxyl groups of nano-ZnO particle surface can interact with carboxyl groups (COO-) of PMAA and form poly(zinc methacrylate) complex on the surface of nano-ZnO. The formation of poly(zinc methacrylate) complex was testified by Fourier-transform infrared spectra (FT-IR). Thermogravimetric analysis (TGA) indicated that PMAA molecules were absorbed or anchored on the surface of nano-ZnO particle, which facilitated to hinder the aggregation of nano-ZnO particles. Through particle size analysis and transmission electron micrograph (TEM) observation, it was found that PMAA enhanced the dispersibility of nano-ZnO particles in water. The dispersion stabilization of modified ZnO nanoparticles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nanoparticles. The modification did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns.

  13. A new setup for the investigation of swift heavy ion induced particle emission and surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Meinerzhagen, F.; Breuer, L.; Bukowska, H.; Herder, M.; Schleberger, M.; Wucher, A. [Fakultät für Physik, Universität Duisburg-Essen and Cenide, 47057 Duisburg (Germany); Bender, M.; Severin, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Lebius, H. [CIMAP (CEA-CNRS-ENSICAEN-UCN), 14070 Caen Cedex 5 (France)

    2016-01-15

    The irradiation with fast ions with kinetic energies of >10 MeV leads to the deposition of a high amount of energy along their trajectory (up to several ten keV/nm). The energy is mainly transferred to the electronic subsystem and induces different secondary processes of excitations, which result in significant material modifications. A new setup to study these ion induced effects on surfaces will be described in this paper. The setup combines a variable irradiation chamber with different techniques of surface characterizations like scanning probe microscopy, time-of-flight secondary ion, and neutral mass spectrometry, as well as low energy electron diffraction under ultra high vacuum conditions, and is mounted at a beamline of the universal linear accelerator (UNILAC) of the GSI facility in Darmstadt, Germany. Here, samples can be irradiated with high-energy ions with a total kinetic energy up to several GeVs under different angles of incidence. Our setup enables the preparation and in situ analysis of different types of sample systems ranging from metals to insulators. Time-of-flight secondary ion mass spectrometry enables us to study the chemical composition of the surface, while scanning probe microscopy allows a detailed view into the local electrical and morphological conditions of the sample surface down to atomic scales. With the new setup, particle emission during irradiation as well as persistent modifications of the surface after irradiation can thus be studied. We present first data obtained with the new setup, including a novel measuring protocol for time-of-flight mass spectrometry with the GSI UNILAC accelerator.

  14. ZnO nanostructures directly grown on paper and bacterial cellulose substrates without any surface modification layer.

    Science.gov (United States)

    Costa, Saionara V; Gonçalves, Agnaldo S; Zaguete, Maria A; Mazon, Talita; Nogueira, Ana F

    2013-09-21

    In this report, hierarchical ZnO nano- and microstructures were directly grown for the first time on a bacterial cellulose substrate and on two additional different papers by hydrothermal synthesis without any surface modification layer. Compactness and smoothness of the substrates are two important parameters that allow the growth of oriented structures.

  15. A directional entrapment modification on the polyethylene surface by the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether

    Science.gov (United States)

    Lu, Qiang; Chen, Yi; Huang, Juexin; Huang, Jian; Wang, Xiaolin; Yao, Jiaying

    2018-05-01

    A novel entrapment modification method involving directional implantation of the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether (AEO) into the high-density polyethylene (HDPE) surface is proposed. This modification technique allows the AEO modifier to be able to spontaneously attain and subsequently penetrate into the swollen HDPE surface with its hydrophobic stearyl segment, while its hydrophilic poly(ethylene oxide) (PEO) segment spontaneously points to water. The AEO modifier with a HLB number below 8.7 was proved appropriate for the directional entrapment, Nevertheless, AEOs with larger HLB numbers were also effective modifiers in the presence of salt additives. In addition, a larger and hydrophobic micelle, induced respectively by the AEO concentration above 1.3 × 10-2 mol/L and the entrapping temperature above the cloud point of AEO, could lead to a sharp contact angle decline of the modified surface. Finally, a hydrophilic HDPE surface with the modifier coverage of 38.9% was reached by the directional entrapment method, which is far larger than that of 19.2% by the traditional entrapment method.

  16. Effect of Rice Husk Surface Modification by LENR the on Mechanical Properties of NR/ HDPE Reinforced Rice Husk Composite

    International Nuclear Information System (INIS)

    Rahmadini Syafri; Ishak Ahmad; Ibrahim Abdullah

    2011-01-01

    Surface modification of rice husk (RH) with alkali pre-treatment (NaOH solution 5 % w/ v) was carried out at the initial state to investigate the effect of surface treatment of fibre on the surface interaction between fibre and rubber. Further modification of RH surfaces after alkali treatment was using Liquid Epoxidized Natural Rubber (LENR) coating at three concentrations, 5 %, 10 %, and 20 % wt LENR solution in toluene. Interfacial morphology and chemical reactions between RH fibre and rubber were analyzed by FTIR and Scanning Electron Microscope (SEM). It was found that 10 % wt LENR solution gave the optimum interaction between fibre and rubber. Matrix and composite blends derived from 60 % natural rubber (NR), 40 % high density polyethylene (HDPE) reinforced with RH fibre were prepared using an internal mixer (Brabender Plasticoder). Result showed that pre-treatment of RH treated with 5 % NaOH followed by treatment with 10 % LENR solution given the maximum interaction between fibre and matrix that gave rise to better mechanical properties of the composites. (author)

  17. High efficient and continuous surface modification of carbon fibers with improved tensile strength and interfacial adhesion

    Science.gov (United States)

    Sun, Jingfeng; Zhao, Feng; Yao, Yue; Jin, Zhen; Liu, Xu; Huang, Yudong

    2017-08-01

    Most of the surface modification technologies for carbon fibers, no matter in laboratory scale or for commercial manufacture, are accompanied by a simultaneous decrease in tensile strength. In this paper, a feasible and high efficient strategy for carbon fiber treatment which could obviously improve both tensile strength and interfacial adhesion was proposed. Continuously moving carbon fibers were treated with atmospheric helium plasma for 1 min, followed by a 5 min pyrolytic carbon deposition using ethanol as precursor at 800 °C. The effects of the new approach were characterized by SEM, AFM, nanoindentation, XPS, Raman, wettability analysis, single fiber tensile strength testing and single fiber pull-out testing. After modification, pyrolytic carbon coating was deposited on the fiber surface uniformly, and the roughness and surface energy increased significantly. The single fiber tensile testing results indicate that the resulting fiber strength increased 15.7%, rising from 3.13 to 3.62 GPa. Meanwhile, the interfacial shear strength of its epoxy composites increased from 65.3 to 83.5 MPa. The comparative studies of carbon fibers modified with commercial anodic oxidation and sizing were also carried out. The results demonstrate that the new method can be utilized in the carbon fiber manufacture process and is more efficient than the traditional approaches.

  18. A Review of Additive Mixed-Electric Discharge Machining: Current Status and Future Perspectives for Surface Modification of Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Abdul’Azeez Abdu Aliyu

    2017-01-01

    Full Text Available Surface treatment remained a key solution to numerous problems of synthetic hard tissues. The basic methods of implant surface modification include various physical and chemical deposition techniques. However, most of these techniques have several drawbacks such as excessive cost and surface cracks and require very high sintering temperature. Additive mixed-electric discharge machining (AM-EDM is an emerging technology which simultaneously acts as a machining and surface modification technique. Aside from the mere molds, dies, and tool fabrication, AM-EDM is materializing to finishing of automobiles and aerospace, nuclear, and biomedical components, through the concept of material migrations. The mechanism of material transfer by AM-EDM resembles electrophoretic deposition, whereby the additives in the AM-EDM dielectric fluids are melted and migrate to the machined surface, forming a mirror-like finishing characterized by extremely hard, nanostructured, and nanoporous layers. These layers promote the bone in-growth and strengthen the cell adhesion. Implant shaping and surface treatment through AM-EDM are becoming a key research focus in recent years. This paper reports and summarizes the current advancement of AM-EDM as a potential tool for orthopedic and dental implant fabrication. Towards the end of this paper, the current challenges and future research trends are highlighted.

  19. JOYO modification program for demonstration tests of FBR innovative technology development

    International Nuclear Information System (INIS)

    Yoshimi, H.; Hachiya, Y.

    1990-01-01

    A plan is under way at PNC to modify the experimental fast reactor JOYO. The project is called MARK-III (MK-III) program. The purpose of MK-III is to expand the function of JOYO, and to make it possible to receive demonstration tests of new or high level technologies for FBR development. The MK-III program consists of two main modifications: conversion to a highly efficient irradiation facility; and a modification for demonstration testing of new technologies and concepts that have a high potential to reduce FBR plant construction cost, to evaluate plant reliability and to improve plant safety. These modifications are scheduled to start in 1991

  20. Nanoparticle-Based Surface Modifications for Microtribology Control and Superhydrophobicity

    Science.gov (United States)

    Hurst, Kendall Matthew

    2010-11-01

    contact" between two contacting surfaces. The studies found that AuNP thin films produced using the lowest initial concentrations of nanoparticles in solution produced estimated real contact areas of around 1%, reducing the adhesion of oxidized Si (100) surfaces from about 37 mJ/m2 down to 0.02 mJ/m 2. In addition, the reducing in real contact area effectively reduced the coefficient of static friction between silicon-based surfaces due to the extremely high dependence of stiction on friction and wear at the microscale. This work also investigated methods of permanently immobilizing AuNP-based films on the silicon surfaces of microstructures in order to create more mechanically robust coatings. The use of organic self-assembled monolayers (SAMs) functionalized with tail-groups known to bond to metallic surfaces were effective in producing much more durable coatings as opposed to non-immobilized AuNP films. Chemical vapor deposition (CVD) techniques were also used to coat rough AuNP films with very thin films of silica (SiO2) to create a robust, rough surface. This method was also very effective in creating a durable coating which is capable of reducing the adhesion energy and friction between two microscale surfaces for extended periods of time. Similar CVD techniques were also used to begin investigating the production of alumina nanoparticle-based superhydrophobic films for use in consumer electronics. Overall, the work presented in this dissertation illustrates that engineered nanoparticle-based surface modifications can be extremely effective in the reduction of the inherent interfacial phenomena that exist on microfabricated systems. This work is can potentially lead us into a new age of the miniaturization of mechanical and electronic devices.

  1. RIKEN 200 kV high current implanter for metal surface modification

    International Nuclear Information System (INIS)

    Iwaki, M.; Yoshida, K.; Sakudo, N.

    1985-01-01

    A high current, metal ion implanter was constructed in order to aid the formation of a new metastable surface alloy. This implanter, called a RIKEN 200 kV high current implanter, is a modified Lintott high current machine (Series III), which has the advantages of having its own microwave ion source and an extra target chamber. The microwave discharge ion source without a hot-filament has a comparatively long lifetime because the chloride ions and radicals in a plasma during discharge of metal chlorides might prevent metal to deposit on the inner walls of the discharge chamber by bombarding and chemically cleaning them. An extra target chamber for metal modification is able to control the surface composition by utilizing the sputtering effect of the ion beam during ion implantation. The use of this ion source and the extra target chamber is suggested to be suitable for the production of metallic ions and for the implantation into metals. The case study will be introduced for TI implantation into Fe. (orig.)

  2. Temperature dependent surface modification of molybdenum due to low energy He+ ion irradiation

    International Nuclear Information System (INIS)

    Tripathi, J.K.; Novakowski, T.J.; Joseph, G.; Linke, J.; Hassanein, A.

    2015-01-01

    In this paper, we report on the temperature dependent surface modifications in molybdenum (Mo) samples due to 100 eV He + ion irradiation in extreme conditions as a potential candidate to plasma-facing components in fusion devices alternative to tungsten. The Mo samples were irradiated at normal incidence, using an ion fluence of 2.6 × 10 24 ions m −2 (with a flux of 7.2 × 10 20 ions m −2 s −1 ). Surface modifications have been studied using high-resolution field emission scanning electron-(SEM) and atomic force (AFM) microscopy. At 773 K target temperature homogeneous evolution of molybdenum nanograins on the entire Mo surface were observed. However, at 823 K target temperature appearance of nano-pores and pin-holes nearby the grain boundaries, and Mo fuzz in patches were observed. The fuzz density increases significantly with target temperatures and continued until 973 K. However, at target temperatures beyond 973 K, counterintuitively, a sequential reduction in the fuzz density has been seen till 1073 K temperatures. At 1173 K and above temperatures, only molybdenum nano structures were observed. Our temperature dependent studies confirm a clear temperature widow, 823–1073 K, for Mo fuzz formation. Ex-situ high resolution X-ray photoelectron spectroscopy studies on Mo fuzzy samples show the evidence of MoO 3 3d doublets. This elucidates that almost all the Mo fuzz were oxidized during open air exposure and are thick enough as well. Likewise the microscopy studies, the optical reflectivity measurements also show a sequential reduction in the reflectivity values (i.e., enhancement in the fuzz density) up to 973 K and after then a sequential enhancement in the reflectivity values (i.e., reduction in the fuzz density) with target temperatures. This is in well agreement with microscopy studies where we observed clear temperature window for Mo fuzz growth

  3. Enhancement of H2-sensing Properties of F-doped SnO2 Sensorby Surface Modification with SiO2

    Directory of Open Access Journals (Sweden)

    S. P. Khatkar

    2006-05-01

    Full Text Available Effects of surface chemical modification with sodium silicate on the gas-sensingproperties of F-doped SnO2 gas sensor designed and fabricated employing micro-electromechanical system (MEMS technology were investigated. Gas sensing properties of thesensor were checked against combustible gases like H2, CO, CH4 and C3H8 at a heatervoltage of 0.7 V. The H2 sensitivity of the surface modified F-doped SnO2 micro sensormarkedly increased and reached S = 175 which was found to be about 40 times more thanthat of unmodified sensor (S = ~ 4.2. The increase in the sensitivity is discussed in terms ofincreased resistivity and reduced permeation of gaseous oxygen into the underlying sensinglayer due to the surface modification of the sensor. The present micro-hydrogen sensor withenhanced sensitivity due to SiO2 incorporation is a low energy consuming portable sensormodule that can be mass-produced using MEMS technology at low cost.

  4. Enhanced biocompatibility of multi-walled carbon nanotubes by surface modification: Future perspectives for drug delivery system

    Science.gov (United States)

    Anandhi, C. M. S.; Asath, R. Mohamed; Mathavan, T.; Benial, A. Milton Franklin

    2017-05-01

    Surface modification of multi-walled carbon nanotubes (MWCNTs) was carried out by introducing mixture of concentrated sulphuric acid and nitric acid by ultrasonication process. The pristine and surface modified MWCNTs were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), Raman spectroscopy and Scanning electron microscopy (SEM) techniques. FT-IR spectra revealed that the presence of carboxylic acid functional groups on the surface of MWCNTs. The integrated intensity ratio of pristine and surface modified MWCNTs was calculated by Raman spectroscopic analysis. XRD patterns examines the crystallinity of the surface modified MWCNTs. SEM analysis investigates the change in morphology of the surface modified MWCNTs compared with that of pristine, which is due to the attachment of the carboxylic acid functional groups. Surface modified MWCNTs acts as precursors for further functionalization with various biomolecules, which improves the biocompatibility and initiates the implementation of MWCNTs in the field of nanomedicine and targeted drug delivery.

  5. Surface Modification of Electrospun PVDF/PAN Nanofibrous Layers by Low Vacuum Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2016-01-01

    Full Text Available Nanofibres are very promising for water remediation due to their high porosity and small pore size. Mechanical properties of nanofibres restrict the application of pressure needed water treatments. Various PAN, PVDF, and PVDF/PAN nanofibre layers were produced, and mechanical properties were improved via a lamination process. Low vacuum plasma treatment was applied for the surface modification of nanofibres. Atmospheric air was used to improve hydrophilicity while sulphur hexafluoride gas was used to improve hydrophobicity of membranes. Hydrophilic membranes showed higher affinity to attach plasma particles compared to hydrophobic membranes.

  6. Synthesis and surface modification of spindle-type magnetic nanoparticles: gold coating and PEG functionalization

    OpenAIRE

    Mendez-Garza , Juan; Wang , Biran; Madeira , Alexandra; Di-Giorgio , Christophe; Bossis , Georges

    2013-01-01

    International audience; In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles w...

  7. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    Czech Academy of Sciences Publication Activity Database

    Mikšovský, Jan; Voss, A.; Kozarova, R.; Kocourek, Tomáš; Písařík, Petr; Ceccone, G.; Kulisch, W.; Jelínek, Miroslav; Apostolova, M.D.; Reithmaier, J.P.; Popov, C.

    2014-01-01

    Roč. 297, APR (2014), s. 95-102 ISSN 0169-4332 R&D Projects: GA MŠk LD12069 Institutional support: RVO:68378271 Keywords : ultrananocrystalline diamond films * diamond -like carbon films * surface modification * direct contact cell tests Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014 http://www.sciencedirect.com/science/article/pii/S0169433214001251

  8. Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes

    Science.gov (United States)

    Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A.; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D.; Knight, Joshua A.; Tun, Han W.; Wharen, Robert E.; Jiang, Wen; Kim, Betty Y. S.

    2016-05-01

    Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines.

  9. Surface modification effects of fluorine-doped tin dioxide by oxygen plasma ion implantation

    Science.gov (United States)

    Tang, Peng; Liu, Cai; Zhang, Jingquan; Wu, Lili; Li, Wei; Feng, Lianghuan; Zeng, Guanggen; Wang, Wenwu

    2018-04-01

    SnO2:F (FTO), as a kind of transparent conductive oxide (TCO), exhibits excellent transmittance and conductivity and is widely used as transparency electrodes in solar cells. It's very important to modifying the surface of FTO for it plays a critical role in CdTe solar cells. In this study, modifying effects of oxygen plasma on FTO was investigated systematically. Oxygen plasma treatment on FTO surface with ion accelerating voltage ranged from 0.4 kV to 1.6 kV has been processed. The O proportion of surface was increased after ion implantation. The Fermi level of surface measurement by XPS valance band spectra was lowered as the ion accelerating voltage increased to 1.2 kV and then raised as accelerating voltage was elevated to 1.6 kV. The work function measured by Kelvin probe force microscopy increased after ion implanting, and it was consistent with the variation of Fermi level. The change of energy band structure of FTO surface mainly originated from the surface composition variation. As FTO conduction was primarily due to oxyanion hole, the carrier was electron and its concentration was reduced while O proportion was elevated at the surface of FTO, as a result, the Fermi level lowered and the work function was enlarged. It was proved that oxygen plasma treatment is an effective method to modulate the energy band structure of the surface as well as other properties of FTO, which provides much more space for interface and surface modification and then photoelectric device performance promotion.

  10. Surface modification of biomaterials based on high-molecular polylactic acid and their effect on inflammatory reactions of primary human monocyte-derived macrophages: perspective for personalized therapy.

    Science.gov (United States)

    Stankevich, Ksenia S; Gudima, Alexandru; Filimonov, Victor D; Klüter, Harald; Mamontova, Evgeniya M; Tverdokhlebov, Sergei I; Kzhyshkowska, Julia

    2015-06-01

    Polylactic acid (PLA) based implants can cause inflammatory complications. Macrophages are key innate immune cells that control inflammation. To provide higher biocompatibility of PLA-based implants with local innate immune cells their surface properties have to be improved. In our study surface modification technique for high-molecular PLA (MW=1,646,600g/mol) based biomaterials was originally developed and successfully applied. Optimal modification conditions were determined. Treatment of PLA films with toluene/ethanol=3/7 mixture for 10min with subsequent exposure in 0.001M brilliant green dye (BGD) solution allows to entrap approximately 10(-9)mol/cm(2) model biomolecules. The modified PLA film surface was characterized by optical microscopy, SERS, FT-IR, UV and TG/DTA/DSC analysis. Tensile strain of modified films was determined as well. The effect of PLA films modified with BGD on the inflammatory reactions of primary human monocyte-derived macrophages was investigated. We developed in vitro test-system by differentiating primary monocyte-derived macrophages on a coating material. Type 1 and type 2 inflammatory cytokines (TNFα, CCL18) secretion and histological biomarkers (CD206, stabilin-1) expression were analyzed by ELISA and confocal microscopy respectively. BGD-modified materials have improved thermal stability and good mechanical properties. However, BGD modifications induced additional donor-specific inflammatory reactions and suppressed tolerogenic phenotype of macrophages. Therefore, our test-system successfully demonstrated specific immunomodulatory effects of original and modified PLA-based biomaterials, and can be further applied for the examination of improved coatings for implants and identification of patient-specific reactions to implants. Copyright © 2015. Published by Elsevier B.V.

  11. Surface Modification Reaction of Photocatalytic Titanium Dioxide with Triethoxysilane for Improving Dispersibility

    International Nuclear Information System (INIS)

    Lee, Myung Jin; Kim, Ji Ho; Park, Young Tae

    2010-01-01

    We have carried out the surface modification of photocatalytic TiO 2 with triethoxysilane through dehydrogenation reaction and characterized the modified photocatalyst by spectroscopic methods, such as FT-IR, solid-state 29 Si MAS NMR, XPS, and XRF, etc. We also examined photocatalytic activity of the immobilized photocatalytic titanium dioxide with triethoxysilane by decolorization reaction of dyes such as cong red and methylene blue under visible light. Dispersion test showed that the photocatalytic titanium dioxide immobilized with triethoxysilane group has kept higher dispersibility than titanium dioxide itself. No appreciable precipitation takes place even after standing for 24 h in the 4:6 mixture ratio of ethanol and water

  12. Surface modification of PTMSP membranes by plasma treatment: Asymmetry of transport in organic solvent nanofiltration.

    Science.gov (United States)

    Volkov, A V; Tsarkov, S E; Gilman, A B; Khotimsky, V S; Roldughin, V I; Volkov, V V

    2015-08-01

    For the first time, the effect of asymmetry of the membrane transport was studied for organic solvents and solutes upon their nanofiltration through the plasma-modified membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP). Plasma treatment is shown to provide a marked hydrophilization of the hydrophobic PTMSP surface (the contact angle of water decreases from 88 down to 20°) and leads to the development of a negative charge of -5.2 nC/cm(2). The XPS measurements prove the formation of the oxygen-containing groups (Si-O and C-O) due to the surface modification. The AFM images show that the small-scale surface roughness of the plasma-treated PTMSP sample is reduced but the large-scale surface heterogeneities become more pronounced. The modified membranes retain their hydrophilic surface properties even after the nanofiltration tests and 30-day storage under ambient conditions. The results of the filtration tests show that when the membrane is oriented so that its modified layer contacts the feed solution, the membrane permeability for linear alcohols (methanol-propanol) and acetone decreases nearly two times. When the modified membrane surface faces the permeate, the membrane is seen to regain its transport characteristics: the flux becomes equal to that of the unmodified PTMSP. The well-pronounced effect of the transport asymmetry is observed for the solution of the neutral dye Solvent Blue 35 in methanol, ethanol, and acetone. For example, the initial membrane shows the negative retention for the Solvent Blue 35 dye (-16%) upon its filtration from the ethanol solution whereas, for the modified PTMSP membrane, the retention increases up to 17%. Various effects contributing to the asymmetry of the membrane transport characteristics are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    Science.gov (United States)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-03-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  14. Synthesis of Silica Nanoparticles by Sol-Gel: Size-Dependent Properties, Surface Modification, and Applications in Silica-Polymer Nano composites-A Review

    International Nuclear Information System (INIS)

    Ismail, A.R.; Vejayakumaran, P.

    2012-01-01

    Application of silica nanoparticles as fillers in the preparation of nano composite of polymers has drawn much attention, due to the increased demand for new materials with improved thermal, mechanical, physical, and chemical properties. Recent developments in the synthesis of monodispersed, narrow-size distribution of nanoparticles by sol-gel method provide significant boost to development of silica-polymer nano composites. This paper is written by emphasizing on the synthesis of silica nanoparticles, characterization on size-dependent properties, and surface modification for the preparation of homogeneous nano composites, generally by sol-gel technique. The effect of nano silica on the properties of various types of silica-polymer composites is also summarized.

  15. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    International Nuclear Information System (INIS)

    Yuan, Yongbing; Chen, Hongling; Lin, Jinbin; Ji, Yan

    2013-01-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  16. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yongbing; Chen, Hongling, E-mail: hlchen@njut.edu.cn; Lin, Jinbin; Ji, Yan

    2013-11-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  17. Layer-by-layer modification of high surface curvature nanoparticles with weak polyelectrolytes using a multiphase solvent precipitation process.

    Science.gov (United States)

    Nagaraja, Ashvin T; You, Yil-Hwan; Choi, Jeong-Wan; Hwang, Jin-Ha; Meissner, Kenith E; McShane, Michael J

    2016-03-15

    The layer-by-layer modification of ≈5 nm mercaptocarboxylic acid stabilized gold nanoparticles was studied in an effort to illustrate effective means to overcome practical issues in handling and performing surface modification of such extremely small materials. To accomplish this, each layer deposition cycle was separated into a multi-step process wherein solution pH was controlled in two distinct phases of polyelectrolyte adsorption and centrifugation. Additionally, a solvent precipitation step was introduced to make processing more amenable by concentrating the sample and exchanging solution pH before ultracentrifugation. The pH-dependent assembly on gold nanoparticles was assessed after each layer deposition cycle by monitoring the plasmon peak absorbance location, surface charge, and the percentage of nanoparticles recovered. The selection of solution pH during the adsorption phase was found to be a critical parameter to enhance particle recovery and maximize surface charge when coating with weak polyelectrolytes. One bilayer was deposited with a high yield and the modified particles exhibited enhanced colloidal stability across a broad pH range and increased ionic strength. These findings support the adoption of this multi-step processing approach as an effective and generalizable approach to improve stability of high surface curvature particles. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Wettability Modification of Nanomaterials by Low-Energy Electron Flux

    Directory of Open Access Journals (Sweden)

    Torchinsky I

    2009-01-01

    Full Text Available Abstract Controllable modification of surface free energy and related properties (wettability, hygroscopicity, agglomeration, etc. of powders allows both understanding of fine physical mechanism acting on nanoparticle surfaces and improvement of their key characteristics in a number of nanotechnology applications. In this work, we report on the method we developed for electron-induced surface energy and modification of basic, related properties of powders of quite different physical origins such as diamond and ZnO. The applied technique has afforded gradual tuning of the surface free energy, resulting in a wide range of wettability modulation. In ZnO nanomaterial, the wettability has been strongly modified, while for the diamond particles identical electron treatment leads to a weak variation of the same property. Detailed investigation into electron-modified wettability properties has been performed by the use of capillary rise method using a few probing liquids. Basic thermodynamic approaches have been applied to calculations of components of solid–liquid interaction energy. We show that defect-free, low-energy electron treatment technique strongly varies elementary interface interactions and may be used for the development of new technology in the field of nanomaterials.

  19. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    Energy Technology Data Exchange (ETDEWEB)

    Šturm, Roman, E-mail: roman.sturm@fs.uni-lj.si [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Štefanikova, Maria [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Steiner Petrovič, Darja [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia)

    2015-01-15

    Graphical abstract: - Highlights: • Heat-treatment protocol for laser surface melting of cold-work tool steel is proposed. • The laser melted steel surface is hardened, and morphologically modified. • The pre-heating of substrate creates a crack-and pore-free steel surface. • The optimum pre-heating temperature is determined to be 350 °C. • Using pre-heating the quantity of retained austenite is reduced. - Abstract: In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides.

  20. Development of Cognitive Bias Modification (CBM) Tools to Promote Adjustment during Reintegration following Deployment

    Science.gov (United States)

    2017-06-01

    a meta-analysis. Child development 73 (3), 916-934. Owen, J.M., 2011. Transdiagnostic cognitive processes in high trait anger. Clinical Psychology ...Award Number: W81XWH-13-2-0001 TITLE: : Development of Cognitive Bias Modification (CBM) Tools to Promote Adjustment during Reintegration...DATES COVERED 15-OCT-2012 TO 14-OCT-2016 4. TITLE AND SUBTITLE Development of Cognitive Bias Modification (CBM) Tools to Promote Adjustment during

  1. Adhesion of nitrile rubber (NBR) to polyethylene terephthalate (PET) fabric. Part 1: PET surface modification by methylenediphenyl di-isocyanate (MDI)

    International Nuclear Information System (INIS)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-01-01

    Graphical abstract: - Highlights: • Glutaric anhydride peroxide (GAP) was grafted on PET surface by UV irradiation method. Then MDI was attached to GAP on PET surface. • The fabric was vulcanized by nitrile rubber. • Peet test was performed after each stage of surface modification. • Curing temperature was increased and the tests were repeated. • Effect of MDI coating on PET without carboxylation was evaluated. Effect of vulcanizing temperature on this product was also studied. - Abstract: Fiber to rubber adhesion is an important subject in rubber composite industry. It is well known that surface physical, mechanical and chemical treatments are effective methods to improve interfacial bonding. Ultra violet (UV) light irradiation is an efficient method which is used to increase interfacial interactions. In this research UV assisted chemical modification of PET fabric was used to increase its bonding to nitrile rubber (NBR). NBR is perfect selection to produce fuel and oil resistant rubber parts but it has weak bonding to fabrics. For this purpose at first, the PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was reacted and grafted to carboxylated PET. T-peel test was used to evaluate PET fabric to NBR bonding strength. Attenuated total reflectance-Fourier transform infrared spectroscopy (FTIR-AT) was used to assess surface modifications of the PET fabrics. The chemical composition of the PET surfaces before and after carboxylation and MDI grafting was investigated by X-ray photoelectron spectroscopy (XPS). It was found that at vulcanizing temperature of 150 °C, carboxylation in contrary to MDI grafting, improved considerably PET to NBR adhesion. Finally effect of curing temperature on PET to NBR bonding strength was determined. It was found that increasing vulcanizing temperature to 170 °C caused considerable improvement (about 134%) in bonding strength.

  2. Interfacing biomembrane mimetic polymer surfaces with living cells - Surface modification for reliable bioartificial liver

    International Nuclear Information System (INIS)

    Iwasaki, Yasuhiko; Takami, Utae; Sawada, Shin-ichi; Akiyoshi, Kazunari

    2008-01-01

    The surface design used for reducing nonspecific biofouling is one of the most important issues for the fabrication of medical devices. We present here a newly synthesized a carbohydrate-immobilized phosphorylcholine polymer for surface modification of medical devices to control the interface with living cells. A random copolymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate (BMA), and 2-lactobionamidoethyl methacrylate (LAMA) was synthesized by conventional radical polymerization. The monomer feeding ratio in the copolymer was adjusted to 24/75/1 (MPC/BMA/LAMA). The copolymer (PMBL1.0) could be coated by solvent evaporation from an ethanol solution. Cells of the human hepatocellular liver carcinoma cell line (HepG2) having asialoglycoprotein receptors (ASGPRs) were seeded on PMBL1.0 or poly(BMA) (PBMA)-coated PET plates. On PBMA, many adherent cells were observed and were well spread with monolayer adhesion. HepG2 adhesion was observed on PMBL1.0 because the cell has ASGPRs. Furthermore, some of the cells adhering to PMBL1.0 had a spheroid formation and similarly shaped spheroids were scattered on the surface. According to confocal laser microscopic observation after 96 h cultivation, it was found that albumin production preferentially occurred in the center of the spheroid. The albumin production of the cells that adhered to PBMA was sparse. The amount of albumin production per unit cell that adhered to PMBL1.0 was determined by ELISA and was significantly higher than that which adhered to PBMA. Long-term cultivation of HepG2 was also performed using hollow fiber mini-modules coated with PMBL1.0. The concentration of albumin produced from HepG2 increased continuously for one month. In the mini-module, the function of HepG2 was effectively preserved for that period. On the hollow fiber membrane, spheroid formation of HepG2 cells was also observed. In conclusion, PMBL1.0 can provide a suitable surface for the cultivation of

  3. Site-selective protein-modification chemistry for basic biology and drug development.

    Science.gov (United States)

    Krall, Nikolaus; da Cruz, Filipa P; Boutureira, Omar; Bernardes, Gonçalo J L

    2016-02-01

    Nature has produced intricate machinery to covalently diversify the structure of proteins after their synthesis in the ribosome. In an attempt to mimic nature, chemists have developed a large set of reactions that enable post-expression modification of proteins at pre-determined sites. These reactions are now used to selectively install particular modifications on proteins for many biological and therapeutic applications. For example, they provide an opportunity to install post-translational modifications on proteins to determine their exact biological roles. Labelling of proteins in live cells with fluorescent dyes allows protein uptake and intracellular trafficking to be tracked and also enables physiological parameters to be measured optically. Through the conjugation of potent cytotoxicants to antibodies, novel anti-cancer drugs with improved efficacy and reduced side effects may be obtained. In this Perspective, we highlight the most exciting current and future applications of chemical site-selective protein modification and consider which hurdles still need to be overcome for more widespread use.

  4. Plasma Surface Modification for Immobilization of Bone Morphogenic Protein-2 on Polycaprolactone Scaffolds

    Science.gov (United States)

    Kim, Byung Hoon; Myung, Sung Woon; Jung, Sang Chul; Ko, Yeong Mu

    2013-11-01

    The immobilization of recombinant human bone formation protein-2 (rhBMP-2) on polycaprolactone (PCL) scaffolds was performed by plasma polymerization. RhBMP-2, which induces osteoblast differentiation in various cell types, is a growth factor that plays an important role in bone formation and repair. The surface of the PCL scaffold was functionalized with the carboxyl groups of plasma-polymerized acrylic acid (PPAA) thin films. Plasma polymerization was carried out at a discharge power of 60 W at an acrylic acid flow rate of 7 sccm for 5 min. The PPAA thin film exhibited moderate hydrophilic properties and possessed a high density of carboxyl groups. Carboxyl groups and rhBMP-2 on the PCL scaffolds surface were identified by attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The alkaline phosphatase activity assay showed that the rhBMP-2 immobilized PCL scaffold increased the level of MG-63 cell differentiation. Plasma surface modification for the preparation of biomaterials, such as biofunctionalized polymer scaffolds, can be used for the binding of bioactive molecules in tissue engineering.

  5. Fabrication and surface properties of hydrophobic barium sulfate aggregates based on sodium cocoate modification

    Science.gov (United States)

    Hu, Linna; Wang, Guangxiu; Cao, Rong; Yang, Chun; Chen, Xi

    2014-10-01

    Hydrophobic barium sulfate aggregates were fabricated by the direction of cocoate anions. At 30 °C, when the weight ratio of sodium cocoate to BaSO4 particles was 2.0 wt.%, the active ratio of the product reached 99.43% and the contact angle was greater than 120°. This method could not only simplify the complex modification process, but reduce energy consumption. The surface morphology, chemical structure and composition of BaSO4 aggregates were characterized by SEM, XRD, and FTIR. The results indicated that the as-synthesized BaSO4 particles were almond-liked and were composed of many interconnected nanoballs and that their surfaces were affected by cocoate anions. The adsorption of cocoate anions reversed the charge and weakened the surface polarity of BaSO4 particles, driving the formation of aggregates. And cocoate anions induced a change of the BaSO4 particles surface from hydrophilic to hydrophobic by a self-assembly and transformation process. Due to the self-assembled structure and the surface hydrophobicity, when adding the hydrophobic BaSO4 into PVC, the mechanical properties of PVC composite materials were significantly improved.

  6. Preparation and surface modification of hierarchical nanosheets-based ZnO microstructures for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Yongming; Lin, Yu, E-mail: linyuyrr@163.com; Lin, Yibing; Yang, Jiyuan

    2014-02-15

    This paper reports a simple one-step hydrothermal route for the preparation of hierarchical nanosheets-based ZnO microstructures and their application to dye-sensitized solar cells. The morphologies of the products were controlled by the dosage of the reactants. Their physical characteristics were detected by X-ray diffraction, a field-emission scanning electron microscope and a surface analyzer. It is proved that the sample of ZnO microspheres with larger surface area and stronger light-trapping capacity since the superiority of their entirely spherical structures exhibits better photoelectrochemical properties than the mixtures of ZnO microspheres and ZnO microflowers. A dye-sensitized solar cell assembled by the ZnO microspheres as photoanode shows an energy conversion efficiency of 2.94% after surface modification by tetrabutyl titanate solution at 90 {sup °}C. This result is over 1.6 times higher than the non-modified cell fabricated by the ZnO microspheres on the basis of the external improvement and the stability enhancement for the dye-sensitized ZnO photoanode. - Graphical abstract: Influences on energy conversion efficiency of the dye-sensitized solar cells assembled by decorating hierarchical nanosheets-based ZnO microstructures with tetrabutyl titanate solution at different temperatures. Display Omitted - Highlights: • Hierarchical nanosheets-based ZnO microstructures were controllably synthesized. • The ZnO microspheres show good optical and electrochemical properties. • The ZnO microspheres were modified by C{sub 16}H{sub 36}O{sub 4}Ti solution. • Remarkable increase of conversion efficiency is observed after surface modification.

  7. Chemical modification of chitosan film via surface grafting of citric acid molecular to promote the biomineralization

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang, E-mail: liuyang@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Shen, Xin; Zhou, Huan [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Wang, Yingjun [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Deng, Linhong, E-mail: dlh@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China)

    2016-05-01

    Graphical abstract: - Highlights: • Chitosan film was modified by surface grafting of citric acid. • The modified film has good hydrophilicity and moisture-retaining capacity. • The citric acid grafting treatment significantly promote the biomineralization. • MC3T3-E1 osteoblasts research confirms the biocompatibility of the film. - Abstract: We develop a novel chitosan–citric acid film (abbreviated as CS–CA) suitable for biomedical applications in this study. In this CS–CA film, the citric acid, which is a harmless organic acid has been extensively investigated as a modifying agent on carbohydrate polymers, was cross-linked by 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto the surface of chitosan (CS) film. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirms the graft copolymerization of the modified chitosan film (CS–CA). Surface wettability, moisturizing performance, the capacity of mineralization in vitro and biocompatibility of the films were characterized. After modification, this CS–CA film has good hydrophilicity. It is very evident that the citric acid grafting treatment significantly promotes the biomineralization of the chitosan based substrates. Cell experiments show that the MC3T3-E1 osteoblasts can adhere and proliferate well on the surface of CS–CA film. This CS–CA film, which can be prepared in large quantities and at low cost, should have potential application in bone tissue engineering.

  8. Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

    International Nuclear Information System (INIS)

    Nikolaev, A.G.; Yushkov, G.Yu.; Oks, E.M.; Oztarhan, A.; Akpek, A.; Hames-Kocabas, E.; Urkac, E.S.; Brown, I.G.

    2014-01-01

    Highlights: • Ion implantation. • Anti-bacterial properties. • Textile polymer. • Vacuum arc ion source. - Abstract: Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal–gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the “inverse” concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material

  9. Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaev, A.G., E-mail: nik@opee.hcei.tsc.ru [High Current Electronics Institute, Siberian Branch of the Russian Academy of Sciences, Tomsk 634055 (Russian Federation); Yushkov, G.Yu.; Oks, E.M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Sciences, Tomsk 634055 (Russian Federation); Oztarhan, A. [Izmir University, Izmir 35140 (Turkey); Akpek, A.; Hames-Kocabas, E.; Urkac, E.S. [Bioengineering Department, Ege University, Bornova 35100, Izmir (Turkey); Brown, I.G. [Lawrence Berkeley National Laboratory, Berkeley, CA 94708 (United States)

    2014-08-15

    Highlights: • Ion implantation. • Anti-bacterial properties. • Textile polymer. • Vacuum arc ion source. - Abstract: Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal–gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the “inverse” concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material.

  10. Low-temperature oxidizing plasma surface modification and composite polymer thin-film fabrication techniques for tailoring the composition and behavior of polymer surfaces

    Science.gov (United States)

    Tompkins, Brendan D.

    This dissertation examines methods for modifying the composition and behavior of polymer material surfaces. This is accomplished using (1) low-temperature low-density oxidizing plasmas to etch and implant new functionality on polymers, and (2) plasma enhanced chemical vapor deposition (PECVD) techniques to fabricate composite polymer materials. Emphases are placed on the structure of modified polymer surfaces, the evolution of polymer surfaces after treatment, and the species responsible for modifying polymers during plasma processing. H2O vapor plasma modification of high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and 75A polyurethane (PU) was examined to further our understanding of polymer surface reorganization leading to hydrophobic recovery. Water contact angles (wCA) measurements showed that PP and PS were the most susceptible to hydrophobic recovery, while PC and HDPE were the most stable. X-ray photoelectron spectroscopy (XPS) revealed a significant quantity of polar functional groups on the surface of all treated polymer samples. Shifts in the C1s binding energies (BE) with sample age were measured on PP and PS, revealing that surface reorganization was responsible for hydrophobic recovery on these materials. Differential scanning calorimetry (DSC) was used to rule out the intrinsic thermal properties as the cause of reorganization and hydrophobic recovery on HDPE, LDPE, and PP. The different contributions that polymer cross-linking and chain scission mechanisms make to polymer aging effects are considered. The H2O plasma treatment technique was extended to the modification of 0.2 microm and 3.0 microm track-etched polycarbonate (PC-TE) and track-etched polyethylene terephthalate (PET-TE) membranes with the goal of permanently increasing the hydrophilicity of the membrane surfaces. Contact angle measurements on freshly treated and aged samples confirmed the wettability of the

  11. Effects of high heat flux hydrogen and helium mixture beam irradiation on surface modification and hydrogen retention in tungsten materials

    International Nuclear Information System (INIS)

    Tokunaga, K.; Fujiwara, T.; Ezato, K.; Suzuki, S.; Akiba, M.; Kurishita, H.; Nagata, S.; Tsuchiya, B.; Tonegawa, A.; Yoshida, N.

    2009-01-01

    High heat flux experiments using a hydrogen-helium mixture beam have been carried out on powder metallurgy tungsten (PM-W) and ultra fine grain W-TiC alloy (W-0.5 wt%TiC-H 2 ). The energy of is 18 keV. Beam flux and heat flux at the beam center is 2.0 x 10 21 atoms/m 2 s and 7.0 MW/m 2 , respectively. Typical ratio of He/D ion is 0.25. Beam duration is 1.5-3 s and interval of beam shot start is 30 s. The samples are irradiated up to a fluence of 10 22 -10 24 He/m 2 by the repeated irradiation pulses. After the irradiation, surface modification by the irradiation and hydrogen retention, surface composition have been investigated. Surface modification by hydrogen-helium mixture beams is completely different from results of single beam irradiation. In particular, mixture beam irradiation causes remarkably high hydrogen retention.

  12. Radiation-curing of acrylate composites including carbon fibres: A customized surface modification for improving mechanical performances

    International Nuclear Information System (INIS)

    Martin, Arnaud; Pietras-Ozga, Dorota; Ponsaud, Philippe; Kowandy, Christelle; Barczak, Mariusz; Defoort, Brigitte; Coqueret, Xavier

    2014-01-01

    The lower transverse mechanical properties of radiation-cured acrylate-based composites reinforced with carbon-fibre with respect to the thermosettable analogues was investigated from the viewpoint of chemical interactions at the interface between the matrix and the carbon material. XPS analysis of representative commercial carbon fibres revealed the presence of a significant amount of chemical functions potentially exerting an adverse effect on the initiation and propagation of the free radical polymerization initiated under high energy radiation. The EB-induced polymerization of n-butyl acrylate as a simple model monomer was conducted in the presence of various aromatic additives exhibiting a strong inhibiting effect, whereas thiols efficiently sensitize the initiation mechanism and undergo transfer reactions. A method based on the surface modification of sized fibres by thiomalic acid is proposed for overcoming the localized inhibition phenomenon and for improving the mechanical properties of the resulting acrylate-based composites. - Highlights: • Surface functions of C-fibres are analyzed for their effect on radical reaction. • Irradiation of nBu-acrylate in presence of aromatic additives reveals inhibition. • Thiol groups sensitize the radiation-initiated polymerization of nBu-acrylate. • Modification of C-fibres with thiomalic acid enhances composite properties

  13. Relative impacts of worldwide tropospheric ozone changes and regional emission modifications on European surface-ozone levels

    International Nuclear Information System (INIS)

    Szopa, S.; Hauglustaine, D.A.

    2007-01-01

    Multi-scale models were applied to assess the surface ozone changes in 2030. Several emission scenarios are considered, ranging from (a) a pessimistic anthropogenic emission increase to (b) an optimistic decrease of emissions, and including (c) a realistic scenario that assumes the implementation of control legislations [CLE]. The two extreme scenarios lead respectively to homogeneous global increase and decrease of surface ozone, whereas low and inhomogeneous changes associated with a slight global increase of ozone are found for the CLE scenario. Over western Europe, for the CLE scenario, the benefit of European emission reduction is significantly counterbalanced by increasing global ozone levels. Considering warmer conditions over Europe and future emission modifications, the human health exposure to surface ozone is found to be significantly worsened. (authors)

  14. Effects of surface modification with hydroxyl terminated polydimethylsiloxane on the corrosion protection of polyurethane coating

    International Nuclear Information System (INIS)

    Jeon, Jae Hong; Shon, Min Young

    2014-01-01

    Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ⅠZⅠ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior

  15. Surface Modification of Titanium with Heparin-Chitosan Multilayers via Layer-by-Layer Self-Assembly Technique

    International Nuclear Information System (INIS)

    Shu, Y.; Zou, J.; Ou, G.; Wang, L.; Li, Q.

    2011-01-01

    Extracellular matrix (ECM), like biomimetic surface modification of titanium implants, is a promising method for improving its biocompatibility. In this paper chitosan (Chi) and heparin (Hep) multilayer was coated on pure titanium using a layer-by-layer (LbL) self-assembly technique. The Hep-Chi multilayer growth was carried out by first depositing a single layer of positively charged poly-L-lysine (PLL) on the NaOH-treated titanium substrate (negatively charged surface), followed by alternate deposition of negatively charged Hep and positively charged Chi, and terminated by an outermost layer of Chi. The multilayer was characterized by DR-FTIR, SEM, and AFM, and osteoblasts were cocultured with the modified titanium and untreated titanium surfaces, respectively, to evaluate their cytocompatibility in vitro. The results confirmed that Hep-Chi multilayer was fabricated gradually on the titanium surface. The Hep-Chi multilayer-coated titanium improved the adhesion, proliferation and differentiation of osteoblasts. Thus, the approach described here may provide a basis for the preparation of modified titanium surfaces for use in dental or orthopedic implants

  16. Deposition of thin films and surface modification by pulsed high energy density plasma

    International Nuclear Information System (INIS)

    Yan Pengxun; Yang Size

    2002-01-01

    The use of pulsed high energy density plasma is a new low temperature plasma technology for material surface treatment and thin film deposition. The authors present detailed theoretical and experimental studies of the production mechanism and physical properties of the pulsed plasma. The basic physics of the pulsed plasma-material interaction has been investigated. Diagnostic measurements show that the pulsed plasma has a high electron temperature of 10-100 eV, density of 10 14 -10 16 cm -3 , translation velocity of ∼10 -7 cm/s and power density of ∼10 4 W/cm 2 . Its use in material surface treatment combines the effects of laser surface treatment, electron beam treatment, shock wave bombardment, ion implantation, sputtering deposition and chemical vapor deposition. The metastable phase and other kinds of compounds can be produced on low temperature substrates. For thin film deposition, a high deposition ratio and strong film to substrate adhesion can be achieved. The thin film deposition and material surface modification by the pulsed plasma and related physical mechanism have been investigated. Thin film c-BN, Ti(CN), TiN, DLC and AlN materials have been produced successfully on various substrates at room temperature. A wide interface layer exists between film and substrate, resulting in strong adhesion. Metal surface properties can be improved greatly by using this kind of treatment

  17. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    International Nuclear Information System (INIS)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun

    2016-01-01

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  18. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun, E-mail: hxjzxh@zju.edu.cn

    2016-11-30

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  19. Influence of a new surface modification of intraocular lenses with fluoroalkylsilan on the adherence of endophthalmitis-causing bacteria in vitro.

    Science.gov (United States)

    Kienast, Antonia; Kämmerer, Regine; Weiss, Claudia; Klinger, Matthias; Menz, Dirk-Henning; Dresp, Joachim; Ohgke, Helge; Solbach, Werner; Laqua, Horst; Hoerauf, Hans

    2006-09-01

    Dynasilan is a fluoroalkylsilan that is able to interact with surface active centres on intraocular lenses (IOL), offering a new way for surface modification of different IOL materials. The purpose of this in vitro study was to investigate the influence of this new surface modification on the adherence of two typical endophthalmitis causing bacteria (Staphylococcus epidermidis, Propionibacterium acnes). In a pilot experiment, the effect of Dynasilan coating on the adherence of S. epidermidis was tested on glass slides. Forty-two Dynasilan-modified and 42 unmodified IOL (14 PMMA, 14 silicone and 14 hydrogel) were incubated at 37 degrees C in brain heart infusion broth (10(8) CFU/ml) with either S. epidermidis for 24 h or with P. acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3x45 s. After dilution series and incubation at 37 degrees C on Petri dishes for 24 h and 3 days, respectively, the colonies were counted. In the pilot experiment, a markedly lower number of adherent S. epidermidis was observed on Dynasilan-modified glass slides. Of all IOL materials incubated with S. epidermidis, those modified with Dynasilan showed a lower mean number of adherent bacteria (mean 1.37x10(7); SD 2.37x10(7)) than those untreated (2.43x10(7); SD 3.04x10(7)). IOLs incubated with P. acnes showed a significantly lower mean number of adherent bacteria of 2.51x10(4) (SD 2.71x10(4)) on Dynasilan-modified IOLs versus 6.27x10(4) (SD 7.70x10(4)) on untreated IOLs. The presented in vitro results indicate that Dynasilan surface modification is able to reduce the adherence of S. epidermidis and P. acnes on all IOL materials tested. Further studies regarding the stability of this modification and its biocompatibility must be performed.

  20. Tribocorrosion studies of metallic biomaterials: The effect of plasma nitriding and DLC surface modifications.

    Science.gov (United States)

    Zhao, Guo-Hua; Aune, Ragnhild E; Espallargas, Nuria

    2016-10-01

    The medical grade pure titanium, stainless steel and CoCrMo alloy have been utilized as biomaterials for load-bearing orthopedic prosthesis. The conventional surgery metals suffer from a combined effect of wear and corrosion once they are implanted, which may significantly accelerate the material degradation process. In this work, the tribocorrosion performance of the metallic biomaterials with different surface modifications was studied in the simulated body fluid for the purpose of investigating the effect of the surface treatments on the tribocorrosion performance and eventually finding the most suitable implantation materials. The metals were subjected to surface modifications by plasma nitriding in different treatment temperatures or physical vapor deposition (PVD) to produce diamond-like carbon (DLC) coating, respectively. The dry wear and tribocorrosion properties of the samples were evaluated by using a reciprocating ball-on-disc tribometer equipped with an electrochemical cell. Prior to the tribocorrosion tests, their electrochemical behavior was measured by the potentiodynamic polarization in phosphate buffer saline (PBS) solution at room temperature. Both stainless steel and CoCrMo after low temperature nitriding kept their passive nature by forming an expanded austenite phase. The DLC coated samples presented the low anodic corrosion current due to the chemical inertness of the carbon layer. During the tribocorrosion tests at open circuit potential, the untreated and low temperature nitrided samples exhibited significant potential drop towards the cathodic direction, which was a result of the worn out of the passive film. Galvanic coupling was established between the depassivated (worn) area and the still passive (unworn) area, making the materials suffered from wear-accelerated corrosion. The DLC coating performed as a solid lubricant in both dry wear and tribocorrosion tests, and the resulting wear after the tests was almost negligible. Copyright