WorldWideScience

Sample records for cationic surface modification

  1. Surface Modification of Bentonites. II. Modification of Montmorillonite with Cationic Poly(ethylene oxides)

    OpenAIRE

    Dau, Jörn; Lagaly, Gerhard

    1998-01-01

    Surface modification of clay minerals has become increasingly important for optimizing the practical application of bentonites, kaolins, and clays. We describe the reaction of montmorillonite, an important mineral in bentonites, with cationic poly(ethylene oxides). Poly(ethylene oxides), PEOs, with molecular masses between 1550 and 35000, were modified by substituting the OH end groups by bromine, then replacing Br by trimethylammonium (TMA) groups. Mono-endcapped PEOs were prepared from poly...

  2. Cation Release Mitigation on the Primary Surface of Alloy 690 Steam Generator Tubes via Electrochemical Surface Modification

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Heesang; Kim, Kyung Mo; Seo, Myung Ji; Han, Jung Ho; Hur, Do Haeng [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The Co-60 and Co-58, major contaminations sources, are formed respectively by neutron activation of Co-59 and Ni-58. Co-59 is originated from various constituting materials such as hardfacing parts (Stellite{sup TM}, Haynes), an impurity in steam generator (SG) tubes, and stainless steel pipes. Ni-58 is mainly released out from the SG tube surface which is about 70% of the total area exposed to the primary coolant. Thus, the corrosion release of Ni ion can be a severe problem at the plant using SG tubes of Ni-based alloys such as Alloy 600 and 690 having high Ni contents. This work provides a mitigation method for the cation corrosion release of commercial Alloy 690 SG tubes in a primary coolant system through electropolishing (EP) surface modification. We modified the inside surface of a commercial Alloy 690 SG tube to investigate the influence of surface condition on the corrosion release rate in the primary coolant system. The change in surface morphologies of corrosion products is negligible, while the corrosion release rate revealed a remarkable improvement by electropolishing of primary surface. In particular, the corrosion release rate is mainly dependent on the surface roughness as a function of EP time. The lowest corrosion release rate was obtained from the sample electro polished for 8 min.

  3. Modification of Nafion Membranes by IL-Cation Exchange: Chemical Surface, Electrical and Interfacial Study

    Directory of Open Access Journals (Sweden)

    V. Romero

    2012-01-01

    A study of time evolution of the impedance curves measured in the system “IL aqueous solution/Nafion-112 membrane/IL aqueous solution” was also performed. This study allows us monitoring the electrical changes associated to the IL-cation incorporation in both the membrane and the membrane/IL solution interface, and it provides supplementary information on the characteristic of the Nafion/DTA+ hybrid material. Moreover, the results also show the significant effect of water on the electrical resistance of the Nafion-112/IL-cation-modified membrane.

  4. Effects of Gas Composition on Highly Efficient Surface Modification of Multi-Walled Carbon Nanotubes by Cation Treatment

    OpenAIRE

    Tseng Chyuan-Yow; Kuo Cheng-Tzu; Tseng Wen-Shou

    2008-01-01

    Abstract High incident energy hydrogen and/or oxygen cations are generated by electron cyclotron resonance system, and then used to highly efficiently modify multi-walled carbon nanotubes (MWCNTs). The effects of various H2/O2 gas compositions on the modification process are studied. A systematic characterization method utilizing a combination of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, Raman spectroscopy, and thermogravimetric analysis (TGA) is used to evaluate t...

  5. Plasma-based surface modifications of polyester fabrics and their interaction with cationic polyelectrolytes and anionic dyes

    OpenAIRE

    Salem, Tarek Sayed Mohamed

    2012-01-01

    Plasma-based surface modifications offer many interesting possibilities for the production of high value-added polymeric materials. In this work, different plasma-based synthetic concepts were employed to endow poly(ethylene terephthalate) (PET) fabrics with accessible amine functionalities. These concepts were compared to find out the appropriate engineering methods, which can be further accepted by textile industries to overcome the limited reactivity of PET fabric surfaces, while the bulk ...

  6. Improved anti-proliferative effect of doxorubicin-containing polymer nanoparticles upon surface modification with cationic groups

    OpenAIRE

    Krovi, Sai Archana; Swindell, Elden P.; O’Halloran, Thomas V.; Nguyen, SonBinh T.

    2012-01-01

    Polymer nanoparticles (PNPs) possessing a high density of drug payload have been successfully stabilized against aggregation in biological buffers after amine modification, which renders these PNPs positively charged. The resulting charge-stabilized PNPs retain their original narrow particle size distributions and well-defined spherical morphologies. This stabilization allows these PNPs to have an improved anti-proliferative effect on MDA-MB-231-Br human breast cancer cells compared to non-fu...

  7. Surface modification of solids

    International Nuclear Information System (INIS)

    The use of ion beam and pulsed laser processing is reviewed for the near-surface modification of a wide range of materials. The techniques of ion implantation doping, ion beam and laser mixing, and pulsed-laser annealing are stressed with particular emphasis on the nonequilibrium aspects of these processing techniques and on new materials properties which can result. Examples are presented illustrating the utility of these techniques for fundamental materials research as well as practical surface modifications

  8. Surface Modification of Multiwall Carbon Nanotubes with Cationic Conjugated Polyelectrolytes: Fundamental Interactions and Intercalation into Conductive Poly(methyl-methacrylate) Composites

    KAUST Repository

    Ezzeddine, Alaa

    2015-05-22

    This research investigates the modification and dispersion and of pristine multiwalled carbon nanotubes (MWCNTs) through a simple solution mixing technique based on noncovalent interactions between poly(phenylene ethynylene) based conjugated polyelectrolytes functionalized with cationic imidazolium solubilizing groups (PIM-2 and PIM-4) and MWCNTs. Spectroscopic studies demonstrated the ability of PIMs to strongly interact with and efficiently disperse MWCNTs in different solvents mainly due to π-interactions between the PIMs and MWCNTs. Transmission electron microscopy and atomic force microscopy revealed the coating of the polyelectrolytes on the walls of the nanotubes. Scanning electron microscopy (SEM) studies confirm the homogenous dispersion of PIM modified MWCNTs in poly(methyl methacrylate) (PMMA) matrix. The addition of 1 wt% PIM modified MWCNTs to the matrix has led to a significant decrease in DC resistivity of the composite (13 orders of magnitude). The increase in electrical conductivity and the improvement in thermal and mechanical properties of the membranes containing the PIM modified MWCNTs is ascribed to the formation of MWCNTs networks and cross-linking sites that provided channels for the electrons to move in throughout the matrix and reinforced the interface between MWCNTs and PMMA.

  9. Surface Modification of Intraocular Lenses

    Institute of Scientific and Technical Information of China (English)

    Qi Huang; George Pak-Man Cheng; Kin Chiu; Gui-Qin Wang

    2016-01-01

    Objective:This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs).Data Sources:All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect.Study Selection:The articles on the surface modification of IOLs were included,but those on design modification and surface coating were excluded.Results:Technology of surface modification included plasma,ion beam,layer-by-layer self-assembly,ultraviolet radiation,and ozone.The main molecules introduced into IOLs surface were poly (ethylene glycol),polyhedral oligomeric silsesquioxane,2-methacryloyloxyethyl phosphorylcholine,TiO2,heparin,F-heparin,titanium,titanium nitride,vinyl pyrrolidone,and inhibitors of cytokines.The surface modification either resulted in a more hydrophobic lens,a more hydrophilic lens,or a lens with a hydrophilic anterior and hydrophobic posterior surface.Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments.Conclusion:The surface modification is an efficient,convenient,economic and promising method to improve the biocompatibility ofIOLs.

  10. Surface Modification of Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Qi Huang

    2016-01-01

    Full Text Available Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs. Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol, polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO 2 , heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

  11. Surface Modification for Microreactor Fabrication

    OpenAIRE

    Wladyslaw Torbicz; Jerzy Kruk; Konrad Dudziński; Roberto Canteri; Michele Vendano; Lorenzo Lunelli; Cecilia Pederzolli; Elżbieta Remiszewska; Pijanowska, Dorota G.

    2006-01-01

    In this paper, methods of surface modification of different supports, i.e. glass and polymeric beads for enzyme immobilisation are described. The developed method of enzyme immobilisation is based on Schiff's base formation between the amino groups on the enzyme surface and the aldehyde groups on the chemically modified surface of the supports. The surface of silicon modified by APTS and GOPS with immobilised enzyme was characterised by atomic force microscopy (AFM), time-of-flight secondary ...

  12. Laser surface modification and adhesion

    CERN Document Server

    Mittal, K L

    2014-01-01

    The book provides a unique overview on laser techniques and applications for the purpose of improving adhesion by altering surface chemistry and topography/morphology of the substrate. It details laser surface modification techniques for a wide range of industrially relevant materials (plastics, metals, ceramics, composites) with the aim to improve and enhance their adhesion to other materials. The joining of different materials is of critical importance in the fabrication of many and varied products.

  13. Biotechnological modification of polyester surfaces

    OpenAIRE

    Nierstrasz, Vincent; Donelli, I; Freddi, G; Smet, Philippe; Poelman, Dirk; Lieva Van LANGENHOVE; Kiekens, Paul

    2010-01-01

    Synthetic fibres form an important part of the textile industry, the production of poly(ethylene terephthalate) (PET) alone surpassing that of cotton. A disadvantage of synthetic fibres is their low hydrophilicity. Polyester fibres are particularly hydrophobic. This affects the processability and functionalisation of the fibres. A novel and promising alternative is the use of enzymes in surface modification of synthetic fibres. Synthetic materials have generally been considered resistant to b...

  14. Colloidal stability by surface modification

    Science.gov (United States)

    Kuchibhatla, Satyanarayana Vnt; Karakoti, A. S.; Seal, Sudipta

    2005-12-01

    The study of colloids is important in the design of materials for uses ranging from pot making to petroleum refining. This review presents the reasons for instability and different methods for attaining stability in various systems of interest. in this context, both steric and electrostatic stabilization are discussed. Also discussed are surface modification in core-shell technology and the importance of surfactants in emulsions.

  15. 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.

  16. 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.

  17. Surface modification of cellulose fibres

    Directory of Open Access Journals (Sweden)

    Mohamed Naceur Belgacem

    2005-06-01

    Full Text Available Several approaches to the modification of cellulose fibres are described, namely: (i physical treatments such as corona or plasma treatments under different atmospheres; (ii grafting with hydrophobic molecules using well-known sizing compounds; (iii grafting with bi-functional molecules, leaving one of the functions available for further exploitation; and (iv grafting with organometallic compounds. The modified surfaces were characterized by elemental analysis, contact angle measurements, inverse gas chromatography, X-ray photoelectron and infrared spectroscopy, wettability, etc. These different tools provided clear-cut evidence of the occurrence of chemical reactions between the grafting agent used and the hydroxy functions of the cellulose surface, as well as of the existence of covalent bonding in the ensuing composite materials between the matrix and the fibres through the use of doubly reactive coupling agents.

  18. Surface modification of cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Neng; DING Enyong; CHENG Rongshi

    2007-01-01

    In order to improve the dispersibility of cellulose nanocrystal(CNC) particles,three difierent grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advantages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier transform infrared spectroscopy(FT-IR),13 C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated mat after desiccation,the modification products could be dispersed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite different.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.

  19. Cellulose nanocrystals : surface modification and advanced materials

    OpenAIRE

    Lin, Ning

    2014-01-01

    The present work focuses on the properties of cellulose nanocrystals, their surface modification and development of advanced materials. Diverse approaches are employed on these nanoscaled substrates aiming to modify their surface properties and extend their use in highly sophisticated applications, such as postsulfation and desulfation, polymer grafting and adsorption, selective oxidation, molecular grafting, and ‘host-guest' inclusion. On the basis of surface modifications, properties analys...

  20. Synergistic effect of cationic and anionic surfactants for the modification of Ca-montmorillonite

    International Nuclear Information System (INIS)

    Highlights: ► The basal spacing of MMT–CTAB–SDS reaches 5.30 nm. ► MMT–CTAB–SDS shows perfect dispersion property and excellent heat resistance. ► SDS helped to improve the heat resistance and decrease the surface energy of the MMT–CTAB–SDS particles. - Abstract: The synergistic effect of cationic surfactant (CTAB) and anionic surfactant (SDS) for the modification of Ca-montmorillonite (Ca-MMT) has been developed, and the novel cation–anion modified organomontmorillonite (MMT–CTAB–SDS) was prepared. X-ray diffraction (XRD) analysis indicates that the interlayer spacing of montmorillonite was well expanded by the intercalation of CTAB and SDS and the basal spacing increased from 1.54 nm (Ca-MMT) to 5.30 nm (MMT–CTAB–SDS). Thermogravimetric analysis (TG) showed that the MMT–CTAB–SDS displayed excellent heat resistance. Scanning electron microscopy (SEM) analysis proved that the MMT–CTAB–SDS exhibited excellent dispersion property and the plates with few silicate layers can be observed. Contact angle tests indicated that the hydrophilicity of MMT–CTAB–SDS was lower than that of Ca-MMT and higher than that of MMT–CTAB. It was verified that SDS contributed to expanding the interlayer space, further improved the heat resistance of the MMT–CTAB and decreased the surface energy of the MMT–CTAB–SDS particles

  1. Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces

    Science.gov (United States)

    Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

    2016-02-01

    Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function.

  2. Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces.

    Science.gov (United States)

    Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

    2016-02-26

    Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function. PMID:26807875

  3. Plasma surface modification of polystyrene and polyethylene

    OpenAIRE

    Guruvenket, S; Rao, Mohan G; Komath, Manoj; Raichur, Ashok M.

    2004-01-01

    Polystyrene (PS) and polyethylene (PE) samples were treated with argon and oxygen plasmas. Microwave electron cyclotron resonance (ECR) was used to generate the argon and oxygen plasmas and these plasmas were used to modify the surface of the polymers. The samples were processed at different microwave powers and treatment time and the surface modification of the polymer was evaluated by measuring the water contact angle of the samples before and after the modification.Decrease in the contact ...

  4. Solution Versus Gas-Phase Modification of Peptide Cations with NHS-Ester Reagents

    Science.gov (United States)

    Mentinova, Marija; Barefoot, Nathan Z.; McLuckey, Scott A.

    2012-02-01

    A comparison between solution and gas phase modification of primary amine sites in model peptide cations with N-hydroxysuccinimide (NHS) ester reagents is presented. In all peptides, the site of modification in solution was directed to the N-terminus by conducting reactions at pH = 5, whereas for the same peptides, a lysine residue was preferentially modified in the gas phase. The difference in pKa values of the N-terminus and ɛ-amino group of the lysine allows for a degree of control over sites of protonation of the peptides in aqueous solution. With removal of the dielectric and multiple charging of the peptide ions in the gas phase, the accommodation of excess charge can affect the preferred sites of reaction. Interaction of the lone pair of the primary nitrogen with a proton reduces its nucleophilicity and, as a result, its reactivity towards NHS-esters. While no evidence for reaction of the N-terminus with sulfo-NHS-acetate was noted in the model peptide cations, a charge inversion experiment using bis[sulfosuccinimidyl] suberate, a cross-linking reagent with two sulfo-NHS-ester functionalities, showed modification of the N-terminus. Hence, an unprotonated N-terminus can serve as a nucleophile to displace NHS, which suggests that its lack of reactivity with the peptide cations is likely due to the participation of the N-terminus in solvating excess charge.

  5. Laser surface modification of metallic biomaterials

    Science.gov (United States)

    Bandyopadhyay, Amit; Balla, Vamsi Krishna; Roy, Mangal; Bose, Susmita

    2011-06-01

    Load-bearing metal implants often fail prematurely due to inadequate biocompatibility, mechanical/tribological properties, and poor osseointegration. It is well known that biomaterials' surface plays a vital role in the response to these metal implants in the biological environment. The biological effectiveness of artificial implants is determined mainly by their surface characteristics such as surface morphology, microstructure, composition, mechanical properties, wettabilility, and surface free energy. Hence, there is significant interest toward surface modification and effective design of load-bearing metal implants so as to improve their surface properties and thereby elicit a specific, desired, and timely response from the surrounding cells and tissues. In this article, we provide an insight into laser surface modification of Ti/Ti6Al4V alloy with or without functional gradation in composition and their microstructural, in vitro wear and biological properties for various loadbearing orthopedic applications.

  6. Surface Modification of Catalytic Materials

    DEFF Research Database (Denmark)

    Nierhoff, Anders Ulrik Fregerslev

    This thesis is a summary of my work on the following systems: Pt alloys for Oxygen Reduction Reaction (ORR) and CO oxidation, Ru for methanation and finally CuZn for methanol synthesis. An important subject throughout the thesis is gas induced surfaces changes. This has been investigated on single...... methanol synthesis. The importance of conducting well controlled UHV experiments and characterization in combination with experiments at higher pressures to span the pressure gap between UHV and operando conditions is definitely highlighted in this thesis....

  7. Surface modification of recording electrodes

    Directory of Open Access Journals (Sweden)

    Iaci Miranda Pereira

    2013-01-01

    Full Text Available Waterborne Polyurethanes (PUs are a family of polymers that contains urethane linkages synthesized in an aqueous environment and are thus free of organic solvents. Recently, waterborne PUs have been extensively studied for biomedical applications because of their biocompatibility. The present work investigates the following: (1 the impact on electrical performance of electrode materials (platinum and silicon modified chemically by a layer of waterborne PU, and (2 the behavior of rat cardiac fibroblasts and rat cardiomyocytes when in contact with an electrode surface. Diisocyanate and poly(caprolactone diol were the main reagents for producing PUs. The electrochemical impedance of the electrode/electrolyte interface was accessed by electrochemical impedance spectroscopy. The cellular viability, proliferation, and morphology changes were investigated using an MTT assay. Cardiomyocyte adherence was observed by scanning electron microscopy. The obtained surface was uniform, flat, and transparent. The film showed good adhesion, and no peeling was detected. The electrochemical impedance decreased over time and was influenced by the ionic permeability of the PU layer. The five samples did not show cytotoxicity when in contact with neonatal rat cells.

  8. Surface Modification of Nanocellulose Substrates

    Science.gov (United States)

    Zoppe, Justin Orazio

    Cellulose fibers constitute an important renewable raw material that is utilized in many commercial applications in non-food, paper, textiles and composite materials. Chemical functionalization is an important approach for improving the properties of cellulose based materials. Different approaches are used to graft polymeric chains onto cellulose substrates, which can be classified by two principal routes, namely 'grafting onto' or 'grafting from' methods. Never-dried cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with various macromolecules. In addition, the use of cellulose nanocrystals to reinforce poly(epsilon-caprolactone) (PCL) nanofibers was studied. Chemical grafting with low molecular weight polycaprolactone diol onto cellulose nanocrystals was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Significant improvements in the mechanical properties of the nanofibers after reinforcement with unmodified cellulose nanocrystals were confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNCs showed ca. 1.5-fold increase in Young's modulus and ultimate strength compared to PCL webs. The CNCs were also grafted with poly(N-isopropylacrylamide) (poly(NiPAAm)) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SETLRP) under various conditions at room temperature. The grafting process depended on the initiator and/or monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. In addition, the colloidal stability and thermo

  9. Surface Modification of Nanocellulose Substrates

    Science.gov (United States)

    Zoppe, Justin Orazio

    Cellulose fibers constitute an important renewable raw material that is utilized in many commercial applications in non-food, paper, textiles and composite materials. Chemical functionalization is an important approach for improving the properties of cellulose based materials. Different approaches are used to graft polymeric chains onto cellulose substrates, which can be classified by two principal routes, namely 'grafting onto' or 'grafting from' methods. Never-dried cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with various macromolecules. In addition, the use of cellulose nanocrystals to reinforce poly(epsilon-caprolactone) (PCL) nanofibers was studied. Chemical grafting with low molecular weight polycaprolactone diol onto cellulose nanocrystals was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Significant improvements in the mechanical properties of the nanofibers after reinforcement with unmodified cellulose nanocrystals were confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNCs showed ca. 1.5-fold increase in Young's modulus and ultimate strength compared to PCL webs. The CNCs were also grafted with poly(N-isopropylacrylamide) (poly(NiPAAm)) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SETLRP) under various conditions at room temperature. The grafting process depended on the initiator and/or monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. In addition, the colloidal stability and thermo

  10. 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 (method to surface vibration for moving drops in microfluidic devices. The final surface modification considered is the application of a thin layer of rubber to a rigid surface. While this technique has many practical uses, such as easy release coatings in marine environments, it is applied herein to enable spontaneous healing between a rubber surface and a glass cover slip. Study of the diffusion controlled healing of a blister can be made by

  11. Surface hopping investigation of the relaxation dynamics in radical cations

    Energy Technology Data Exchange (ETDEWEB)

    Assmann, Mariana; Matsika, Spiridoula, E-mail: smatsika@temple.edu [Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States); Weinacht, Thomas [Department of Physics, Stony Brook University, Stony Brook, New York 11794 (United States)

    2016-01-21

    Ionization processes can lead to the formation of radical cations with population in several ionic states. In this study, we examine the dynamics of three radical cations starting from an excited ionic state using trajectory surface hopping dynamics in combination with multiconfigurational electronic structure methods. The efficiency of relaxation to the ground state is examined in an effort to understand better whether fragmentation of cations is likely to occur directly on excited states or after relaxation to the ground state. The results on cyclohexadiene, hexatriene, and uracil indicate that relaxation to the ground ionic state is very fast in these systems, while fragmentation before relaxation is rare. Ultrafast relaxation is facilitated by the close proximity of electronic states and the presence of two- and three-state conical intersections. Examining the properties of the systems in the Franck-Condon region can give some insight into the subsequent dynamics.

  12. Gamma-irradiated cationic starches: Paper surface-sizing agents

    International Nuclear Information System (INIS)

    Cationic starches, precisely depolymerized by gamma-irradiation (60Co), were dispersed in mild alkali and evaluated as surface sizes for bond paper on a pilot paper machine. The irradiated products had excellent dispersion properties, were well retained on fibers when sized wastepaper (broke) was repulped and had an ability to enhance paper properties that was comparable to that of starch-based materials used commercially. A yellow corn flour, cationized by an essentially dry reaction process recently developed at this Center, was also radiolyzed and evaluated as a size. This latter product was unique in that all drying steps were eliminated in the preparation of a cationic ceral product of reduced viscosity. (orig.)

  13. Biocompatibility of Cation Coated on Plasma-Polymerized Ti Surface

    Science.gov (United States)

    Lee, Kang; Ko, Yeong-Mu; Kim, Byung-Hoon

    2012-08-01

    In this study, we investigated the bone formation properties and cell responses on Na-, Mg-, K-, and Ca-ion-exchanged carboxyl plasma polymerized titanium (Ti) surfaces. The phase and morphologies of deposits bonelike apatite were significantly influence by the cation species. Na and Mg ions promote bonelike apatite nucleation and growth on plasma-functionalized Ti surfaces in simulated body fluid (SBF) and improves the crystallinity of the bonelike apatite deposited layer. The cell viability tests revealed significantly enhanced viability on the Ca-ion-exchanged plasma-functionalized Ti surface than on any other surface.

  14. Surface modification with ionised cluster beams: Modelling

    International Nuclear Information System (INIS)

    Impacts of accelerated cluster ions which consist of hundreds of atoms on a solid surface have shown new surface smoothing and roughening effects. Hybrid Molecular Dynamics (MD) and a two-dimensional MD method were used to simulate rapid collision processes at the target impact zone and the subsequent thermalization. Gas clusters impacting on metal and semiconductor target surfaces have been considered to study the ripple formation under irradiation with oblique cluster beams. The dynamics of surface modification is simulated by using a discrete model which contains crater formation and surface relaxation. The continuum description of a surface relaxation is based on a dynamics equation for surface heights containing viscous flow, surface tension, surface diffusion, and crater formation terms. Comparison of the results of the simulation with experimental data shows qualitative agreement

  15. Mechanism of Surface Modification for Sericite

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification of sericite by wet method was conducted with the addition of 1.0% (w/w) silane. The resulting wetting contact angle and activity ratio of sericite were 130° and 98% respectively.Good pre-evaluation indexes of oil value (40.8%) and dispersivity (14.0 mL) were obtained. When 30% of sericite was filled into acrylonitrile butadiene styrene(ABS) plastic, the bending strength and tensile strength of the composite material were reduced by 7% and 14.3% in comparison to those of pure ABS plastic, while the rigidity was increased by 3 times, and the impact strength and breaking elongation were reduced significantly.The mechanism of surface modification was investigated and the configuration of silane coupling agent on the surface of sericite was given. Infrared (IR) spectroscopic analysis indicates that the adsorption of silane on the surface of sericite belongs to chemical adsorption.

  16. MODIFICATION OF TRANSITION METAL CATIONS TO POLYMER- STABILIZED PLATINUM COLLOIDAL CLUSTERS IN ENANTIOSELECTIVE HYDROGENATION OF METHYL PYRUVATE

    Institute of Scientific and Technical Information of China (English)

    Xiao-ping Yan; Bao-lin He; Jie Zhang; Han-fan Liu

    2005-01-01

    Modification of transition metal cations to polymer-stabilized Pt colloidal clusters modified with cinchonidine was studied in enantioselective hydrogenation of methyl pyruvate. Compared to the enantiomeric excess (e.e.) value (71.4%)obtained without the presence of metal cations, obvious e.e. enhancement (up to 82.5%) was resulted from the addition of Zn2+ but with a certain decrease in activity. The reaction parameters in the presence of Zn2+ were also studied. It was found that the Pt colloidal catalysts in the presence of metal cations performed very differently from that in the absence of metal cations.

  17. Surface modification of nanodiamond in aqueous medium

    Institute of Scientific and Technical Information of China (English)

    许向阳; 朱永伟; 王柏春; 沈湘黔

    2003-01-01

    The methods of chemical-mechanical treatments(CMT)were utilized for surface modification of nanodiamond in aqueous medium,and a considerably stable suspension system was thus obtained.The size of all the particles in the provided system was less than 100 nm with a narrow distribution and excellent stability,and no obvious change of particle crystal structure after the treatments was observed.The mechanism of the treatments was also discussed.The results show that,because of mechanical treatment effect,addition of ionic surfactants and inorganic regulators,the ζ-potential of nanodiamond shifts upwards during the treatments,and the composition of surface functional groups changes.Carboxyl and hydroxyl groups are intensified after the surface modification,which may contribute to the improvement of dispersion and stability.Meanwhile,the addition of non-ionic polymer can also benefit the suspension stability.

  18. Modification of surface energy in nuclear multifragmentation

    International Nuclear Information System (INIS)

    Within the statistical multifragmentation model we study modifications of the surface and symmetry energy of primary fragments in the freeze-out volume. The ALADIN experimental data on multifragmentation obtained in reactions induced by high-energy projectiles with different neutron richness are analyzed. We have extracted the isospin dependence of the surface energy coefficient at different degrees of fragmentation. We conclude that the surface energy of hot fragments produced in multifragmentation reactions differs from the values extracted for isolated nuclei at low excitation. At high fragment multiplicity, it becomes nearly independent of the neutron content of the fragments

  19. Surface modification: advantages, techniques, and applications

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    2000-03-01

    Adequate performance of materials at elevated temperatures is a potential problem in many systems within the chemical, petroleum, process, and power-generating industries. Degradation of materials occurs because of interaction between the structural material and the exposure environment. These interactions are generally undesired chemical reactions that can lead to accelerated wastage and alter the functional requirements and/or structural integrity of the materials. Therefore, material selection for high-temperature applications must be based not only on a material strength properties but also on resistance to the complex environments prevalent in the anticipated exposure environment. As plants become larger, the satisfactory performance and reliability of components play a greater role in plant availability and economics. However, system designers are becoming increasingly concerned with finding the least expensive material that will satisfactorily perform the design function for the desired service life. This present paper addresses the benefits of surface modification and identified several criteria for selection and application of modified surfaces in the power sector. A brief review is presented on potential methods for modification of surfaces, with the emphasis on coatings. In the final section of the paper, several examples address the requirements of different energy systems and surface modification avenues that have been applied to resolve the issues.

  20. Synthesis of Branch Fluorinated Cationic Surfactant and Surface Properties

    Directory of Open Access Journals (Sweden)

    Hongke Wu

    2014-01-01

    Full Text Available A novel fluorinated quaternary ammonium salt cationic surfactant N,N,N-trimethyl-2-[[4-[[3,4,4,4-tetrafluoro-2-[1,2,2,2-tetrafluoro-1-(trifluoromethylethyl]-1,3-bis(tri-fluoromethyl-1-buten-1-yl]oxy]-benzoyl]amino]-iodide (FQAS was synthesized successfully, and its structure was characterized by FTIR, 1H-NMR, 19F-NMR, and MS. The surface activities of FQAS and the effect of temperature, electrolyte, and combination with hydrocarbon surfactant were investigated. The results showed that FQAS exhibited excellent surface activity and combination with hydrocarbon surfactant.

  1. Nanofibrillated Cellulose Surface Modification: A Review

    OpenAIRE

    Julien Bras,; Mohamed Naceur Belgacem; Karim Missoum

    2013-01-01

    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 fa...

  2. Modification of cation-exchange properties of activated carbon by treatment with nitric acid

    International Nuclear Information System (INIS)

    The uptake of inorganic cations by high-surface-area activated carbon can be increased by an order of magnitude by controlled exposure to high concentrations of nitric acid at elevated temperatures. Distribution coefficients of cations are also increased. Oxidation treatment causes some loss in particle strength. Acid strength of the functional groups from the nitric acid treatment is greater than those of the starting material. Surface area measurements from small-angle neutron scattering indicate that the increase in effective ion-exchange capacity is not accompanied by gross changes in the structure of the material. 13C-NMR on solid samples suggests that the concentration of carboxyl and phenolic functional groups in the carbon is increased by the treatment

  3. Surface modification of polycarbonate by plasma treatment

    International Nuclear Information System (INIS)

    The surfaces of polycarbonate films were treated by nitrogen plasma, in order to understand the effect of low energy ions on the surface modification of polycarbonate. The modified samples were characterized by micro-hardness tester, optical micrograph/atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and FTIR spectroscopy. It was observed that the hardness of the film increases as fluence increases. This may be attributed to the cross-linking effect as corroborated with FTIR spectra. XPS analysis indicates that chemical bonding on the surface of the film, especially C=O, C-O and C-C/C-H functional groups, was found to change due to plasma treatment. AFM analysis reveals that average surface roughness increases from 5.9 nm to 42.7 nm as fluence increases.

  4. Material surface modifications with an inductive plasma

    International Nuclear Information System (INIS)

    We report on the application of a radiofrequency plasma to surface treatment of materials. Plasma is produced in a low pressure flowing gas by means of an external coil, to prevent direct interaction of the plasma with the radiofrequency electrode. Very stable and steady plasma conditions have been obtained. The plasma state has been characterized by Langmuir probes and optical emission spectroscopy to relate the physical properties of the plasma to the induced surface modifications. The source was applied to perform plasma treatments on a PVC film, in order to obtain a conductive surface layer. We report a preferential removal of chlorine and a superficial generation of C = C double bonds. Imaging of the surface with a FIB/SEM microscope revealed the partial conductivity of the sample and the presence of bidimensional clusters with average radius of about 200 nm

  5. Surface modification of barite nanoparticles using stearate

    Institute of Scientific and Technical Information of China (English)

    LI Lin-lin; HANG Jian-zhong; SHI Li-yi

    2009-01-01

    In this study,the barite nanoparticles were successfully modified with stearate and the influence of stearate addition on the performance of barite nanoparticles was systematically investigated.The products were characterized by activating factor analysis,contact angle test,surface energy calculation,sedimentation rate calculation,rheological measurement,and FT-IR analysis,etc.As the quantity of added stearate increased,both the activating factor and contact angle of barite nanoparticles increased first then decreased.When the stearate content was 5% of the mass of barite nanoparticles,the activating factor and water contact angle of modified particles reached maximum value,97% and 126~ respectively.At this time,the sedimentation rate reached minimum,and so did the surface energy.The rheological test reveals that the viscosity of modified barite nanoparticles/ petronol system decreases greatly,indicating the surface performance of barite nanoparticles has changed from hydrophilicity to lipophilicity after modification.C=O and COO stretching vibration peaks were found in the FT-IR spectra,which proves that the stearate has combined onto the surface of barite nanoparticles.Finally,according to the zeta potential result of unmodified barite,the possible modification mechanism was provided.

  6. Non-Surface Activity of Cationic Amphiphilic Diblock Copolymers

    International Nuclear Information System (INIS)

    Cationic amphiphilic diblock copolymers containing quaternized poly (2-vinylpyridine) chain as a hydrophilic segment (PIp-b-PNMe2VP) were synthesized by living anionic polymerization. By IR measurement, we confirmed the quaternization of the polymer (PIp-b-PNMe2VP), and determined the degree of quaternization by conductometric titration. The surface tension experiment showed that the polymers are non-surface active in nature. The foam formation of the polymer solutions was also investigated with or without added salt. Almost no foam formation behavior was observed without added salt, while a little foam was observed in the presence of 1M NaCl. The critical micelle concentration (cmc) of the diblock copolymers with 3 different chain lengths was measured by the static light scattering method. The cmc values obtained in this study were much lower than the values obtained for anionic non-surface active diblock polymers studied previously. The hydrodynamic radii of the polymer micelle increased slightly in the presence of 1 M NaCl. The transmission electron microscopic images revealed spherical micelles in pure water. In the presence of salt, the cmc values increased as was the case for anionic polymers, which is unlike conventional surfactant systems but consistent with non-surface active anionic block copolymers. The microviscosity of the micelle core was evaluated using Coumarin-153 as a fluorescent anisotropy probe using steady-sate fluorescence depolarization. Non-surface activity has been proved to be universal for ionic amphiphilic block copolymers both for anionic and cationic. Hence, the origin of non-surface activity is not the charged state of water surface itself, but should be an image charge repulsion at the air/water interface.

  7. Surface modifications of some nanocomposites containing starch

    Science.gov (United States)

    Pascu, M.-C.; Popescu, M.-C.; Vasile, C.

    2008-09-01

    Polymer-layered silicate nanocomposites have attracted strong interest in today's materials research, due to the possible impressive enhancements of material properties, comparatively with those of pure polymers. Several starch/poly(vinylalcohol)/montmorillonite nanocomposites have been subjected to surface modification by physical treatments such as dielectric barrier discharge (DBD) exposure and coating with proteins (albumin) or polysaccharides (chitosan), for improving their biocompatibility. Untreated and treated surfaces have been comparatively studied by contact angle measurements, FT-IR and 2D-FT-IR spectroscopy and optical microscopy. It has been established that enhancement of the surface characteristics depends on the type and number of incorporated nanoparticles as well as on the treatment applied. Coupling of DBD exposure and coating techniques appears to be highly efficient.

  8. Surface modification of polypropylene based particle foams

    Science.gov (United States)

    Schreier, P.; Trassl, C.; Altstädt, V.

    2014-05-01

    This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

  9. Atmospheric pressure plasma for surface modification

    CERN Document Server

    Wolf, Rory A

    2012-01-01

    This Book's focus and intent is to impart an understanding of the practical application of atmospheric plasma for the advancement of a wide range of current and emerging technologies. The primary key feature of this book is the introduction of over thirteen years of practical experimental evidence of successful surface modifications by atmospheric plasma methods. It offers a handbook-based approach for leveraging and optimizing atmospheric plasma technologies which are currently in commercial use. It also offers a complete treatment of both basic plasma physics and industrial plasma process

  10. Surface modification of polyethylene by plasma

    International Nuclear Information System (INIS)

    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

  11. Kinetic study of the binding of triplex-forming oligonucleotides containing partial cationic modifications to double-stranded DNA.

    Science.gov (United States)

    Hari, Yoshiyuki; Ijitsu, Shin; Akabane-Nakata, Masaaki; Yoshida, Takuya; Obika, Satoshi

    2014-07-15

    Several triplex-forming oligonucleotides (TFOs) partially modified with 2'-O-(2-aminoethyl)- or 2'-O-(2-guanidinoethyl)-nucleotides were synthesized and their association rate constants (kon) with double-stranded DNA were estimated by UV spectrophotometry. Introduction of cationic modifications in the 5'-region of the TFOs significantly increased the kon values compared to that of natural TFO, while no enhancement in the rate of triplex DNA formation was observed when the modifications were in the middle and at the 3'-region. The kon value of a TFO with three adjacent cationic modifications at the 5'-region was found to be 3.4 times larger than that of a natural one. These results provide useful information for overcoming the inherent sluggishness of triplex DNA formation. PMID:24865415

  12. Surface modification of Nano filtration and Ultrafiltration commercial membranes by adsorption of polyelectrolyte multilayers: Surface characterization and desalination performances

    International Nuclear Information System (INIS)

    Recent developments in membrane technology are made essentially in the field of surface modification in order to tune selectivity and to decrease fouling. In the present study, we investigate the surface modification and the characterization of two thin film composite membranes made of polyamide. The selected membranes belong to Nano filtration with opened pores (GH) and to Ultrafiltration with tight pores (GM). The surface modification of both membranes was made chemically in the first step by grafting acrylic acid and physically in the second step by alternating adsorption of oppositely charged poly electrolytes. The active surfaces of the bare commercial membranes and of the modified ones were morphologically characterized by atomic force microscopy; and by FTIR-ATR. Desalination performances of these membranes were determined with synthetic salt solutions with different ion valences before and after surface modification. Hydraulic permeability of NF membranes dropped for all salt solutions. Retention rate of salt solutions containing divalent cations is reduced while those containing divalent anions and monovalent ions have seen their retention rate increased. With UF membranes, hydraulic permeability is increased globally. Retention of salt solutions containing divalent anions is improved whereas retention of salts with divalent cations and monovalent ions is decreased.

  13. Surface modification of cellulose by PCL grafts

    Energy Technology Data Exchange (ETDEWEB)

    Paquet, Olivier; Krouit, Mohammed; Bras, Julien [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France); Thielemans, Wim [Driving Innovation in Chemistry and Chemical Engineering (DICE), School of Chemistry and Process and Environmental Research Division - Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Belgacem, Mohamed Naceur, E-mail: Naceur.Belgacem@efpg.inpg.fr [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France)

    2010-02-15

    Two cellulosic substrates (microcrystalline cellulose, MCC, and bleached kraft softwood pulps, BSK) were grafted by polycaprolactone (PCL) chains with different molecular weights, following a three-step procedure using non-swelling conditions in order to limit the reaction to their surface. First, one of the two OH PCL ends was blocked by phenyl isocyanate and the reaction product (adduct 1) was subsequently reacted with 2,4-toluene diisocyanate (adduct 2) to provide it with an NCO function, capable of reacting with cellulose. The ensuing PCL-grafted cellulosic materials were characterized by weight gain, elemental analysis, contact angle measurements, attenuated total reflexion-Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and biodegradation tests. The modification was proven to occur by the presence of nitrogen atoms in the elemental analysis tests and XPS spectra of modified and soxhlet-extracted cellulose. The contact angle measurements have also shown that the surface became as hydrophobic as PCL itself. The polar component of the surface energy of cellulosic substrates before treatment was found to be about 32 and 10 mJ m{sup -2}, for MCC and BSK, respectively. This value vanished to practically zero after grafting with different PCLs. The strategy proposed in the present work is original since, to the best of our knowledge, this paper reports for the first time the chemical 'grafting onto' of the cellulose surface by PCL macromolecular structures, with the aim of obtaining fibre-matrix co-continuous fully sustainable and biodegradable composite materials.

  14. Chemical modification of a polyacrylamide. Enhanced decontamination of soils and surfaces after a nuclear accident

    International Nuclear Information System (INIS)

    This contribution concerns the decontamination of soils and surfaces polluted by cesium and strontium after a nuclear accident. The decontamination rate by means of an industrial polyacrylamide previously selected for its mechanical covering properties is studied. The characteristics of the polymer and its cation-exchange capacity (CEC) are specified. The chemical modification of the polymer, involving a crosslinking path and functional grafting, affords an improvement of its decontaminating properties. (author). 6 refs., 4 figs., 1 tab

  15. Modification of bentonite with cationic surfactant for the enhanced retention of bisphenol A from landfill leachate.

    Science.gov (United States)

    Li, Yi; Jin, Fenglai; Wang, Chao; Chen, Yunxiao; Wang, Qing; Zhang, Wenlong; Wang, Dawei

    2015-06-01

    Bentonite was modified with cationic surfactant hexadecyl trimethyl ammonium bromide (HTAB) as landfill liner to retard the transportation of bisphenol A (BPA) for the first time. The modification was confirmed to form a lateral bi-layer in the interlayer space of bentonite by scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy. The introduction of HTAB into the internal position of bentonite led to an increased interlayer space of bentonite from 15.0 to 20.9 Å and a higher sorption affinity for BPA (10.449 mg/g of HTAB-bentonite and 3.413 mg/g of raw bentonite). According to the Freundlich model, the maximum adsorption capacity of the HTAB-bentonite was found to be 0.410 mg/g. The sorption capacity of raw bentonite and HTAB-bentonite both decreased at alkaline conditions. Although the hydraulic conductivity of HTAB-bentonite was higher than that of raw bentonite, results of laboratory permeability and column tests indicated that HTAB-bentonite obviously extended the BPA breakthrough time by 43.4 %. The properties of the HTAB-bentonite revealed its notable advantages as components of landfill liners material to retain BPA in leachate. PMID:25874420

  16. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

    Science.gov (United States)

    Rodriguez, Carlos; Papanastasiou, Emilios; Juba, Melanie; Bishop, Barney

    2014-09-01

    The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs) and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we’ve explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  17. Covalent modification of a ten-residue cationic antimicrobial peptide with levofloxacin

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Rodriguez

    2014-09-01

    Full Text Available The rampant spread of antibiotic resistant bacteria has spurred interest in alternative strategies for developing next-generation antibacterial therapies. As such, there has been growing interest in cationic antimicrobial peptides (CAMPs and their therapeutic applications. Modification of CAMPs via conjugation to auxiliary compounds, including small molecule drugs, is a new approach to developing effective, broad-spectrum antibacterial agents with novel physicochemical properties and versatile antibacterial mechanisms. Here, we’ve explored design parameters for engineering CAMPs conjugated to small molecules with favorable physicochemical and antibacterial properties by covalently affixing a fluoroquinolone antibiotic, levofloxacin, to the ten-residue CAMP Pep-4. Relative to the unmodified Pep-4, the conjugate was found to demonstrate substantially increased antibacterial potency under high salt concentrations. Historically, it has been observed that most CAMPs lose antibacterial effectiveness in such high ionic strength environments, a fact that has presented a challenge to their development as therapeutics. Physicochemical studies revealed that P4LC was more hydrophobic than Pep-4, while mechanistic findings indicated that the conjugate was more effective at disrupting bacterial membrane integrity. Although the inherent antibacterial effect of the incorporated levofloxacin molecules did not appear to be substantially realized in this conjugate, these findings nevertheless suggest that covalent attachment of small molecule antibiotics with favorable physicochemical properties to CAMPs could be a promising strategy for enhancing peptide performance and overall therapeutic potential. These results have broader applicability to the development of future CAMP-antibiotic conjugates for potential therapeutic applications.

  18. Gasemission and surface modifications during helium implantation on nickel surfaces

    International Nuclear Information System (INIS)

    Simultaneous measurements are reported of the helium reemission and the surface modifications of poly- and single crystal nickel surfaces during helium ion-implantation at energie between 20 keV-150 keV in the temperature range 250C-9500C. In addition the He depth-profiles have been measured using the nuclear reaction method 3H(d,α)H. The binding characteristics of He in nickel is studied by isochronous annealing of the samples after the implantation process and a subsequent measurement of the desorption spectra, and the surfaces are investigated by optical microscopy and scanning electron microscopy. For all implantation energies and impact temperatures together with the surface modifications a simultaneous increase in helium reemission is observed at a critical fluency value, which depends on temperature and implantation energy. A qualitative explanation of the empirical relation between reemission rate and blister formation rate is given on the basis of a lateral stress model for blister formation. (orig./GSCH)

  19. Surface modification of Ti-surfaces by alginate polyelectrolyte layers

    Czech Academy of Sciences Publication Activity Database

    Kubies, Dana; Pop-Georgievski, Ognen; Mázl Chánová, Eliška; Zemek, Josef; Neykova, Neda; Demianchuk, Roman; Houska, Milan; Filová, Elena; Bačáková, Lucie; Rypáček, František

    Liverpool : European Society for Biomaterials, 2014. P314. [Annual Conference European Society for Biomaterials /26./. 31.08.2014-03.09.2014, Liverpool] R&D Projects: GA MZd(CZ) NT13297; GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:68378271 ; RVO:67985823 Keywords : surface modification * titanium * alginate Subject RIV: CD - Macromolecular Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D); EI - Biotechnology ; Bionics (FGU-C)

  20. Theoretical Investigation on the Adsorption of Ag+ and Hydrated Ag+ Cations on Clean Si(111)Surface

    Institute of Scientific and Technical Information of China (English)

    SHENG Yong-Li; LI Meng-Hua; WANG Zhi-Guo; LIU Yong-Jun

    2008-01-01

    In this paper,the adsorption of Ag+ and hydrated Ag+ cations on clean Si(111)surface were investigated by using cluster(Gaussian 03)and periodic(DMol3)ab initio calculations.Si(111)surface was described with cluster models(Si14H17 and Si22H21)and a four-silicon layer slab with periodic boundary conditions.The effect of basis set superposition error(BSSE)was taken into account by applying the counterpoise correction.The calculated results indicated that the binding energies between hydrated Ag+ cations and clean Si(111)surface are large,suggesting a strong interaction between hydrated Ag+ cations and the semiconductor surface.With the increase of number,water molecules form hydrogen bond network with one another and only one water molecule binds directly to the Ag+ cation.The Ag+ cation in aqueous solution will safely attach to the clean Si(111)surface.

  1. 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 of...

  2. Modification of potato peel waste with base hydrolysis and subsequent cationization.

    Science.gov (United States)

    Lappalainen, Katja; Kärkkäinen, Johanna; Joensuu, Päivi; Lajunen, Marja

    2015-11-01

    Potato peel waste (PW) is a starch containing biomaterial produced in large amounts by food processing industry. In this work, the treatment of PW by alkaline hydrolysis and cationization in the water phase is reported. In order to improve the cationization of starch, PW was hydrolyzed by heating with alkaline (NaOH) ethanol solution (80%) in a water bath. The impact of variable molar ratios of anhydroglucose unit (AGU):NaOH, heating temperatures and times was studied on the degradation of starch and the molecular size distribution of the product. The hydrolyzed PW was cationized subsequently in water by using glycidyltrimethylammonium chloride and catalyzed by NaOH under microwave irradiation or in an oil bath. The impact of the various reaction conditions on the cationization and degree of substitution of starch was studied. The degree of substitution of the cationized starch varied in the range of 0-0.35. PMID:26256329

  3. Surface-Active and Performance Properties of Cationic Imidazolinium Surfactants Based on Different Fatty Acids

    Science.gov (United States)

    Bajpai, Divya; Tyagi, V. K.

    Imidazoline surfactants belong to the category of cationic surfactants. Cationic surfactants are often quaternary nitrogen salts and are widely used both in nonaqueous systems and in applications such as textile softeners, dispersants, and emulsifiers. This study describes the surface-active properties of cationic imidazolinium surfactants synthesized from different fatty acids. Their laundry performance in combination with nonionic surfactants like detergency, foaming property, softening property, rewettability etc., is also emphasized.

  4. The Progress on Laser Surface Modification Techniques of Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    LIANG Cheng; PAN Lin; Al Ding-fei; TAO Xi-qi; XIA Chun-huai; SONG Yan

    2004-01-01

    Titanium alloy is widely used in aviation, national defence, automobile, medicine and other fields because of their advantages in lower density, corrosion resistance, and fatigue resistance etc. As titanium alloy is higher friction coefficients, weak wear resistance, bad high temperature oxidation resistance and lower biocompatibility, its applications are restricted. Using laser surface modification techniques can significantly improve the surface properties of titanium alloy. a review is given for progress on laser surface modification techniques of titanium alloy in this paper.

  5. Surface area of lipid membranes regulates the DNA-binding capacity of cationic liposomes

    Science.gov (United States)

    Marchini, Cristina; Montani, Maura; Amici, Augusto; Pozzi, Daniela; Caminiti, Ruggero; Caracciolo, Giulio

    2009-01-01

    We have applied electrophoresis on agarose gels to investigate the DNA-binding capacity of cationic liposomes made of cationic DC-cholesterol and neutral dioleoylphosphatidylethanolamine as a function of membrane charge density and cationic lipid/DNA charge ratio. While each cationic liposome formulation exhibits a distinctive DNA-protection ability, here we show that such a capacity is universally regulated by surface area of lipid membranes available for binding in an aspecific manner. The relevance of DNA protection for gene transfection is also discussed.

  6. Computer simulation of surface modification with ion beams

    International Nuclear Information System (INIS)

    Niobium surface modification dynamics treated by cluster ion irradiation was studied based on atomistic and mesoscopic simulation methods and the results were compared to experiments. A surface smoothening method was proposed consisting of a treatment of the Nb cavity surfaces by accelerated gas (argon) cluster ion beams (GCIB) that is capable of reducing the surface roughness up to the theoretical limit

  7. Surface modification of materials to encourage beneficial biofilm formation

    Directory of Open Access Journals (Sweden)

    Amreeta Sarjit

    2015-10-01

    Full Text Available Biofilms are communities of sessile microorganisms that grow and produce extrapolymeric substances on an abiotic or biotic surface. Although biofilms are often associated with negative impacts, the role of beneficial biofilms is wide and include applications in bioremediation, wastewater treatment and microbial fuel cells. Microbial adhesion to a surface, which is highly dependent on the physicochemical properties of the cells and surfaces, is an essential step in biofilm formation. Surface modification therefore represents an important way to modulate microbial attachment and ultimately biofilm formation by microorganisms. In this review different surface modification processes such as organosilane surface modification, plasma treatment, and chemical modification of carbon nanotubes, electro-oxidation and covalent-immobilization with neutral red and methylene blue molecules are outlined. The effectiveness of these modifications and their industrial applications are also discussed. There is inadequate literature on surface modification as a process to enhance beneficial biofilm formation. These methods need to be safe, economically viable, scalable and environmental friendly and their potential to fulfil these criteria for many applications has yet to be determined.

  8. Advances of Titanium Alloys and Its Biological Surface Modification

    Institute of Scientific and Technical Information of China (English)

    XU Ke-wei; HUANG Ping

    2004-01-01

    This paper reviews the past, present and future of surface modification of titanium alloy from the point of view of preparation of hard tissue replacement implants. The development of titanium alloy is also described.

  9. A SCANNING TUNNELING MICROSCOPE FOR SURFACE MODIFICATION

    OpenAIRE

    M. McCord; Pease, R

    1986-01-01

    With the recent success for the scanning tunneling microscope (STM) has come question of whether the instrument might be used for material modifications lithography. We embarked on the design of an STM with this application in mind. Its features include a wide x-y piezoelectric scan range of 10 or more microns, plus coarse mechanical motion in the x direction to a new region on the sample while in vacuum. Coarse motion in the z direction is accomplished with a micrometer drive, while fine mov...

  10. MICROWAVE-ASSISTED SURFACE MODIFICATION OF CALCIUM BICARBONATE

    Institute of Scientific and Technical Information of China (English)

    Jing Ye; Xiaofei Zhang

    2004-01-01

    Surface modification of calcium bicarbonate powder with isopropyl triisostearoyl titanate (TTS) by microwave-assisted heating was studied in the present work. The features of microwave treated powder show obvious superiority to those of powder samples treated by traditional surface modification method and of untreated calcium bicarbonate - in suspension turbidity, suction potential, contact angle with water, and mechanical properties of their composites with PVC resin.

  11. Chemical Surface, Thermal and Electrical Characterization of Nafion Membranes Doped with IL-Cations

    Directory of Open Access Journals (Sweden)

    María del Valle Martínez de Yuso

    2014-04-01

    Full Text Available Surface and bulk changes in a Nafion membrane as a result of IL-cation doping (1-butyl-3-methylimidazolium tetrafluoroborate or BMIM+BF4 and phenyltrimethylammonium chloride or TMPA+Cl− were studied by X-ray photoelectron spectroscopy (XPS, contact angle, differential scanning calorimetry (DSC and impedance spectroscopy (IS measurements performed with dry samples after 24 h in contact with the IL-cations BMIM+ and TMPA+. IL-cations were selected due to their similar molecular weight and molar volume but different shape, which could facilitate/obstruct the cation incorporation in the Nafion membrane structure by proton/cation exchange mechanism. The surface coverage of the Nafion membrane by the IL-cations was confirmed by XPS analysis and contact angle, while the results obtained by the other two techniques (DSC and IS seem to indicate differences in thermal and electrical behaviour depending on the doping-cation, being less resistive the Nafion/BMIM+ membrane. For that reason, determination of the ion transport number was obtained for this membrane by measuring the membrane or concentration potential with the samples in contact with HCl solutions at different concentrations. The comparison of these results with those obtained for the original Nafion membrane provides information on the effect of IL-cation BMIM+ on the transport of H+ across wet Nafion/BMIM+ doped membranes.

  12. Effect of Surface Modification on Behaviors of Cerium Oxide Nanopowders

    Institute of Scientific and Technical Information of China (English)

    Li Mei; Shi Zhenxue; Liu Zhaogang; Hu Yanhong; Wang Mitang; Li Hangquan

    2007-01-01

    Study was made on the effect of surface modification on the behaviors of cerium oxide nanopowders. A surfactant-sodium dodecyl sulfate(C12H25SO4Na) was used to modify the surface of CeO2 powder particles. The unmodified and modified CeO2 powders were characterized by using a powder comprehensive characteristic tester, laser particle size analyzer, specific surface area tester, X-ray diffraction tester, and a scanning electron microscope. The testing and analysis results showed that C12H25SO4Na surface modification might increase the flowability and dispersity, and decrease the specific surface area and agglomeration of CeO2 powders. The mechanism of the surface modification of CeO2 powder particles was also discussed.

  13. 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 and......-span bridges can now produce more than 50% of the overall horizontal load on the bridge (Gimsing and Georgakis, 2012). Recently, the authors presented a comprehensive comparative study of the aerodynamic performance of these existing cable surface modifications (Kleissl and Georgakis, 2011, 2012). The...

  14. RF-ARGON PLASMA INDUCED SURFACE MODIFICATION OF PAPER

    OpenAIRE

    HALIL TURGUT SAHIN

    2008-01-01

    The radio frequency (RF) argon plasma induced surface modification of paper revealed novel surface characteristics and substantially changed surface topography. It was found that RF-argon glow discharge affects surface properties resulting in photo-degradation and chain-scission mechanism on paper network structure. High-power and extended treatment time caused increasing elemental carbon, while decreasing the oxygen concentration on paper surface. However, increased hydroxyls and the creatio...

  15. Polymer grafting modification of the surface of nano silicon dioxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the composite modification technology of the surface of nano silicon dioxide by non-soap emulsion polymerization, it is verified that there are polymer grafted on the surface of nano silicon dioxide. The modification mechanism and the bonding status on the surface of nano silicon dioxide after modification were suggested via the results of the infrared spectrum, transmission electronic microscope photograph and X-ray photoelectron spectrum. The hydroxyl formed by hydrolyzing of silane coupling agent reacts with hydroxyl on the surface of nano silicon dioxide to form Si-O-Si bonds by losing water molecules and hence the double bonds are introduced onto the surface of nano silicon dioxide. The surface of nano silicon dioxide is grafted with polymer through free radical polymerization between the double bonds on the surface of nano silicon dioxide and styrene under the action of initiating agent. The dispersibility of nano silicon dioxide and the controllability of surface modification of nano silicon dioxide can be greatly improved by the modification process.

  16. Surface modifications with Lissajous trajectories using atomic force microscopy

    International Nuclear Information System (INIS)

    In this paper, we report a method for atomic force microscopy surface modifications with single-tone and multiple-resolution Lissajous trajectories. The tip mechanical scratching experiments with two series of Lissajous trajectories were carried out on monolayer films. The scratching processes with two scan methods have been illustrated. As an application, the tip-based triboelectrification phenomenon on the silicon dioxide surface with Lissajous trajectories was investigated. The triboelectric charges generated within the tip rubbed area on the surface were characterized in-situ by scanning Kelvin force microscopy. This method would provide a promising and cost-effective approach for surface modifications and nanofabrication

  17. Bioinspired catecholic chemistry for surface modification.

    Science.gov (United States)

    Ye, Qian; Zhou, Feng; Liu, Weimin

    2011-07-01

    The attachment strategy based on catecholic chemistry has been arousing renewed interest since the work on polymerized catecholic amine (polydopamine) (Messersmith et al., Science, 2007, 318, 426) was published. Catechols and their derived compounds can self-assemble on various inorganic and organic materials, including noble metals, metals, metal oxides, mica, silica, ceramics and even polymers. It opens a new route to the modification of various substrates and the preparation of functional composite materials by simple chemistry. However, there is still not a full review so far about the attachment chemistry despite the dramatically increasing number of publications. This critical review describes the state-of-the-art research in the area: the design and synthesis of catecholic molecules, their adsorption mechanisms and the stability of assemblies in solution, and their applications etc. Some perspectives on future development are raised (195 references). PMID:21603689

  18. Surface modification and characterization of impregnated paper

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shaoxia, E-mail: shwang@abo.fi [Abo Akademi University, Laboratory of Paper Coating and Converting, Center of Excellence for Functional Materials (FUNMAT), FI-20500 Turku (Finland); Mahlberg, Riitta; Kaukoniemi, Otto-Ville [Technical Research Centre of Finland (VTT), P.O. Box 1000, 02044 Espoo (Finland); Nikkola, Juha; Mannila, Juha [Technical Research Centre of Finland (VTT), P.O. Box 1300, 33101 Tampere (Finland); Jaemsae, Saila; Ritschkoff, Anne-Christine [Technical Research Centre of Finland (VTT), P.O. Box 1000, 02044 Espoo (Finland); Peltonen, Jouko [Abo Akademi University, Department of Physical Chemistry, Center of Excellence for Functional Materials (FUNMAT), FT-20500 Turku (Finland)

    2012-03-01

    Two organic-inorganic hybrid sol-gel coatings were developed in order to modify the surface energy and moisture behaviour of the commercial impregnated paper. The surface characteristics of the paper samples were studied by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). It was found that the applied sol-gel coatings as well as the curing process changed the surface structural and chemical properties of the impregnated paper. The chemical bonding between the hydroxyl groups present on paper surface and silanol groups from sol-gel coatings was confirmed by the FTIR spectra. The measured surface energies divided into polar and dispersive components indicated that the coating B resulted in less polar surface than did the coating A which was more polar than the reference (the impregnated paper with water and heat treatment). Coating B brought about the lowest total surface energy. It was obtained that the water repellence of the impregnated paper was improved by both coatings and the curing process.

  19. Surface modification and characterization of impregnated paper

    International Nuclear Information System (INIS)

    Two organic-inorganic hybrid sol-gel coatings were developed in order to modify the surface energy and moisture behaviour of the commercial impregnated paper. The surface characteristics of the paper samples were studied by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). It was found that the applied sol-gel coatings as well as the curing process changed the surface structural and chemical properties of the impregnated paper. The chemical bonding between the hydroxyl groups present on paper surface and silanol groups from sol-gel coatings was confirmed by the FTIR spectra. The measured surface energies divided into polar and dispersive components indicated that the coating B resulted in less polar surface than did the coating A which was more polar than the reference (the impregnated paper with water and heat treatment). Coating B brought about the lowest total surface energy. It was obtained that the water repellence of the impregnated paper was improved by both coatings and the curing process.

  20. Surface modification of polymeric materials by cold atmospheric plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kostov, K.G., E-mail: kostov@feg.unesp.br [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Nishime, T.M.C.; Castro, A.H.R. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Toth, A. [Institute of Material and Environmental Chemistry, Hungarian Academy of Science P.O. Box 17, H-1525, Budapest (Hungary); Hein, L.R.O. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil)

    2014-09-30

    Highlights: • We investigate polymer surface modification by atmospheric pressure plasma jet APPJ. • Jet operation conditions for uniform surface modification were determined. • The APPJ added O atoms to the polymer surface and also enhanced the roughness. • The degree of polymer surface modification by APPJ and DBD were compared. • The APPJ is more efficient in attaching O atoms and produces less polymer fragments. - Abstract: In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source – the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  1. Surface modification of YIG by magnet array

    Science.gov (United States)

    Atalay, S.; Kolat, V. S.; Bakır, H. G.; Izgi, T.; Kaya, A. O.; Kaya, O. A.; Gencer, H.

    2015-11-01

    In this work, magnetostatic surface spin waves (MSSW) were propagated along the single crystal YIG (Y3Fe5O12) film grown on GGG substrate. In order to obtain magnonic crystals, unlike the conventional methods, the surface of YIG films were magnetically modulated by magnet array in one and two-dimensions. The surface modulated YIG films formed sharp band gaps at approximately 6.55 GHz and 6.58 GHz at 1600 Oe magnetic field for one and two-dimensional magnonic crystals, respectively. It was found that a very small magnetic field change leads a large change in the peak value of band gap frequency.

  2. Enzymatic surface modification of acrylonitrile fibers

    Science.gov (United States)

    Battistel, Ezio; Morra, Marco; Marinetti, Massimo

    2001-06-01

    The surface of polyacrylonitrile polymer (containing 10% acetate groups) as fibers and finely ground powder have been modified by enzymatic treatment. The enzyme used was a nitrile hydratase, member of the class of nitrile converting enzymes, present in the microorganisms Brevibacterium imperiale and Corynebacterium nitrilophilus. The pendant nitrile groups were selectively converted into the corresponding amides as assessed by XPS analysis. As indicated by the increase of the O/C atomic ratio, the fiber surface showed a significant increase in hydrophilicity. The newly formed amide groups were then able to react with the acid dyes typically used to stain natural fibers, conferring the coloring properties to the otherwise inert polymer surface.

  3. Ion-induced surface modification of alloys

    International Nuclear Information System (INIS)

    In addition to the accumulation of the implanted species, a considerable number of processes can affect the composition of an alloy in the surface region during ion bombardment. Collisions of energetic ions with atoms of the alloy induce local rearrangement of atoms by displacements, replacement sequences and by spontaneous migration and recombination of defects within cascades. Point defects form clusters, voids, dislocation loops and networks. Preferential sputtering of elements changes the composition of the surface. At temperatures sufficient for thermal migration of point defects, radiation-enhanced diffusion promotes alloy component redistribution within and beyond the damage layer. Fluxes of interstitials and vacancies toward the surface and into the interior of the target induce fluxes of alloying elements leading to depth-dependent compositional changes. Moreover, Gibbsian surface segregation may affect the preferential loss of alloy components by sputtering when the kinetics of equilibration of the surface composition becomes competitive with the sputtering rate. Temperature, time, current density and ion energy can be used to influence the individual processes contributing to compositional changes and, thus, produce a rich variety of composition profiles near surfaces. 42 references

  4. Surface modifications by field induced diffusion.

    Directory of Open Access Journals (Sweden)

    Martin Olsen

    Full Text Available By applying a voltage pulse to a scanning tunneling microscope tip the surface under the tip will be modified. We have in this paper taken a closer look at the model of electric field induced surface diffusion of adatoms including the van der Waals force as a contribution in formations of a mound on a surface. The dipole moment of an adatom is the sum of the surface induced dipole moment (which is constant and the dipole moment due to electric field polarisation which depends on the strength and polarity of the electric field. The electric field is analytically modelled by a point charge over an infinite conducting flat surface. From this we calculate the force that cause adatoms to migrate. The calculated force is small for voltage used, typical 1 pN, but due to thermal vibration adatoms are hopping on the surface and even a small net force can be significant in the drift of adatoms. In this way we obtain a novel formula for a polarity dependent threshold voltage for mound formation on the surface for positive tip. Knowing the voltage of the pulse we then can calculate the radius of the formed mound. A threshold electric field for mound formation of about 2 V/nm is calculated. In addition, we found that van der Waals force is of importance for shorter distances and its contribution to the radial force on the adatoms has to be considered for distances smaller than 1.5 nm for commonly used voltages.

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

    Science.gov (United States)

    Rahimi, M.; Fojan, P.; Gurevich, L.; Afshari, A.

    2014-03-01

    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 roughness was also observed.

  6. Synthesis, characterization and chemical modification of a cationic polyelectrolyte poly(methylene amine)

    OpenAIRE

    Kundu, Nihar Ranjan

    2007-01-01

    Polyamine polymers have attracted attention due to their ability to demonstrate pH dependent cationic nature and presence of highly reactive pendant amino groups. These amino groups make them suitable for a host of applications through cross-linking and derivatization. As a result the end use application of a polyamine is largely driven by the number of amino groups and the way they are attached to the polymer backbone. Thus, this piece of work describes the synthesis and investigation of pro...

  7. Optimizing the lifetimes of phenoxonium cations derived from vitamin E via structural modifications.

    Science.gov (United States)

    Yue, Yanni; Novianti, Maria L; Tessensohn, Malcolm E; Hirao, Hajime; Webster, Richard D

    2015-12-28

    Systematic synthesis of a number of new phenolic compounds with structures similar to vitamin E led to the identification of several sterically hindered compounds that when electrochemically oxidised in acetonitrile in a -2e(-)/-H(+) process formed phenoxonium diamagnetic cations that were resistant to hydrolysis reactions. The reactivity of the phenoxonium ions was ascertained by performing cyclic voltammetric scans during the addition of carefully controlled quantities of water into acetonitrile solutions, with the data modelled using digital simulation techniques. PMID:26480893

  8. 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

  9. Surface modification and characterization Collaborative Research Center at ORNL

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. 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.

  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 are a

  13. Surface modification of titanium by plasma nitriding

    OpenAIRE

    Myriam Pereira Kapczinski; Carlos Gil; Eder Julio Kinast; Carlos Alberto dos Santos

    2003-01-01

    A systematic investigation was undertaken on commercially pure titanium submitted to plasma nitriding. Thirteen different sets of operational parameters (nitriding time, sample temperature and plasma atmosphere) were used. Surface analyses were performed using X-ray diffraction, nuclear reaction and scanning electron microscopy. Wear tests were done with stainless steel Gracey scaler, sonic apparatus and pin-on-disc machine. The obtained results indicate that the tribological performance can ...

  14. Improved Surface Modification Approach for Micromechanical Biosensors

    OpenAIRE

    Gao, Hongyan; Buchapudi, Koutilya R.; Harms-Smyth, Abraham; Schulte, Marvin K; Xu, Xiaohe; Ji, Hai-Feng

    2007-01-01

    We have investigated the sensing performance of protein-based microcantilever biosensors prepared from multiple surface conjugation chemistries. The 11-mercaptoundecanoic acid monolayers were prepared according to both traditional and modified processes. In three protein-based biosensors, the modified process improved microcantilever sensing performance by increasing the bending amplitude, a critical step toward developing a cost-effective microcantilever-based sensor platform for medical dia...

  15. Surface modification of solid state gas sensors

    CERN Document Server

    Morris, L

    2000-01-01

    mechanism of the room temperature CO response of SnO sub 2 decorated with small Pt particles was refined. In this case Pt was applied by common impregnation techniques. The conductivity was shown to be controlled by the surface state of the Pt. The CO response at room temperature was found to be specific to the presence of Pt(ll) species. The mechanism was assigned to CO chemisorption onto Pt(ll), resulting in charge transfer, measured as conductivity increase. The samples were characterized by XPS, TPD, SEM, mass spectrometry and electrical measurements. Comparison of the results presented for Pt decorated BaSn sub 0 sub . sub 9 sub 7 Sb sub 0 sub . sub 0 sub 3 O sub 3 and BaFeO sub 3 demonstrated the phenomenon to be general providing that Pt particles act as surface traps, controlling the conductivity. The phenomenon of electrical conductivity being controlled by the chemical state of a surface grafted reactive centre, resulting in a room temperature gas response, is demonstrated. The reactive centres can ...

  16. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    International Nuclear Information System (INIS)

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe3+ > Al3+ > Cu2+ >> Ca2+ > K+ > Na+, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na+-smectite and K+-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe3+, Al3+, and Cu2+ are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O2−· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation

  17. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Hanzhong, E-mail: jiahz@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Li, Li [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Chen, Hongxia; Zhao, Yue [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); School of Geology and Mining Engineering, Xinjiang University, Urumqi 830046 (China); Li, Xiyou [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Wang, Chuanyi, E-mail: cywang@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)

    2015-04-28

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe{sup 3+} > Al{sup 3+} > Cu{sup 2+} >> Ca{sup 2+} > K{sup +} > Na{sup +}, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na{sup +}-smectite and K{sup +}-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe{sup 3+}, Al{sup 3+}, and Cu{sup 2+} are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O{sub 2}{sup −}· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation.

  18. The Modification of Ferroelectric Surfaces for Catalysis

    Science.gov (United States)

    Herdiech, Matthew William

    Ferroelectrics are a class of materials in which a net dipole can be associated with each repeat unit, resulting in a potentially large electric field through the material. The ability to reversibly switch the polarization direction by applying an external electric field distinguishes ferroelectrics from polar orientations of ordinary materials. Recent studies exploring the reactivity of ferroelectric surfaces toward polar molecules have shown that the heats of adsorption for these molecules are polarization dependent, but the surfaces tend to be unreactive. Despite the inertness of ferroelectric surfaces, their use as supports for catalytically active materials could yield novel reactivity. As even metal oxides that are generally considered inert can influence the catalytic properties of supported layers, a ferroelectric support may offer the opportunity to modulate catalytic activity since charge compensation of the polar surfaces might include chemical and electronic reconstructions of the active layer. In this thesis, the fabrication of active layers with polarization dependent properties was investigated by coating ferroelectric substrates with catalytically active oxides that are likely to grow in a layer-by-layer manner. Two systems in particular were explored: chromium oxide on ferroelectric lithium niobate (Cr2O3/LiNbO3), and ruthenium oxide on ferroelectric lead zirconate titanate (RuO2/Pb(Zr0.2Ti0.8)O 3). The chromium oxide and ruthenium oxide films were characterized with X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and reflection high energy electron diffraction (RHEED). Additionally, the chromium oxide films were characterized with X-ray diffraction (XRD) and X-ray reflectivity (XRR) measurements, and the ruthenium oxide films were characterized with ion scattering spectroscopy (ISS) measurements. The reactivity of the films was investigated using temperature programmed desorption (TPD) measurements. In particular

  19. Surface modification of metals using plasma torch

    International Nuclear Information System (INIS)

    Low temperature plasma nitriding of 304l stainless steel is performed by using a home made, low power direct-current plasma torch . Plasma nitriding is carried out in temperature range of 300 -550 degree C for 1 to 4 hours, in various N2-H2 gas mixture ratios at about 5 Torr pressure and of torch power 300 watts. The effect of treatment time, temperature and working gas composition on the microstructure and mechanical properties of plasma nitrided surface layers is investigated. The microstructure, phase composition and micro hardness profile of the nitrided surface layers are investigated by optical microscopy, scanning electron microscope (SEM),X-ray diffraction (XRD) and Vickers micro hardness tester. The results show that plasma treatment for 1-4 h over a temperature range of 300-550 degree C yields nitride case depth of 20-50 μm and the hardness of the nitrided layer is in a range of 700-1200 HV. Plasma nitriding of stainless steel samples at about 475 degree C in 70% of nitrogen admixed with hydrogen at 5 torr shows the maximum increase of hardness 1220 HV which is about four times that of untreated layers. The XRD pattern confirmed the formation of an expanded austenite γN phase , due to the nitrogen incorporation into original lattice and forms supersaturated face center cubic phase. In addition preliminary results for aluminum nitriding is also considered.

  20. Laser-induced surface modification and metallization of polymers

    Science.gov (United States)

    Frerichs, Hartmut; Wesner, David A.; Kreutz, Ernst-Wolfgang

    1995-04-01

    Laser-induced surface modification of various polymers is presented as a suitable pretreatment of surfaces in a two-step metallization process. Materials such as polyamide (PA), polypropylene (PP), polystyrene (PS), polycarbonate (PC), acrylbutadienestyrene (ABS), styreneacrylnitril (SAN), polybutadieneterphtalate (PBT), and polyoxymethylen (POM) were treated by excimer laser radiation ((lambda) equals 248 nm) in air. The aim of this study is to investigate different processing regimes of surface modification. Therefore the laser processing variables fluence F, repetition rate v and pulse number N are varied and the absorption coefficient, optical penetration depth, ablation depth and ablation threshold are determined. The surface morphology and surface roughness are studied by optical surface profilometry and secondary electron microscopy (SEM). The influence of laser treatment on chemical composition of modified and ablated surfaces is analyzed by X-ray photoelectron spectroscopy (XPS). Depending on the processing parameters and materials properties different microstructures and values of surface roughness are generated on the micrometer length scale. Pretreatment for the subsequent metallization is performed with laser radiation, wet chemical and plasma etching. The metallization of polymers is investigated for different surface morphologies. The used metallization processes are electroplating and physical vapor deposition (PVD). Adhesion of the deposited films, measured with scratch and tape test methods, is used as a criterion for determining regimes of suitable surface modification for subsequent metallization.

  1. Steam Initiated Surface Modification of Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud

    detailed analysis of the structure and morphology of the coating, and interface structure with and without organic top coat. Corrosion performance of the coatings was investigated using electrochemical methods, AASS, and FFC test. The morphology, microstructure, chemical composition, adhesion, and......The extensive demand of aluminium alloys in various industries such as in transportationis mainly due to the high strength to weight ratio, which could be translated into fuel economy and efficiency. Corrosion protection of aluminium alloys is an important aspect for all applications which includes......-friendly alternative processes. In the present work high temperature steam-based process has been investigated as a possible chromate free conversion coating. Investigations in the thesis includes the effect of alloy type, substrate microstructure, surface finish, and various chemistries on the coating formation, and...

  2. Surface Modification Mechanism of Fine Coal by Electrochemical Methods

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong; WANG Fang-hui; WANG Dian-zuo; OU Ze-shen

    2006-01-01

    In order to reveal the surface modification mechanism of fine coal by electrochemical methods, the structural changes of the coal surface before and after electrochemical modification were investigated by Fourier Transform Infrared Spectra (FTIR) and Raman Spectra. The results show that under certain electrochemical conditions, the oxygen-containing functional group in the coal structure and the oxygen content of absorption could be reduced and the floatability of coal improved. At the same time, the sulfur in the coal was reduced to the hydrophilic S2- which could be separated easily from coal. Thus electrochemical modification methods could be used to change the structure and functional group on the coal surface and to enhance the floatability of coal.

  3. Surface modification of ZnO nanocrystals

    International Nuclear Information System (INIS)

    Nano-crystalline ZnO particles were synthesized using alcoholic solutions of zinc acetate dihydrate through a colloidal process. Five types of capping agents: 3-aminopropyl trimethoxysilane (Am), tetraethyl orthosilicate (TEOS), mercaptosuccinic acid (Ms), 3-mercaptopropyl trimethoxysilane (Mp) and polyvinylpyrrolidone (Pv) were added at the first ZnO precipitation time (first PPT) to limit the particle growth. The first three capping agents effectively capped the ZnO nanoparticles and limited the growth of the particles, while the last two capping agents caused agglomeration or larger clusters in the solutions. Particles synthesized were in the size range of 10-30 nm after capping, and grew to 60 and 100 nm in 3 and 6 weeks, respectively, during storage at ambient conditions. Refluxing time was found to only affect the first PPT time. Washing by ethanol and slow drying were very important in converting Zn(OH)2 into ZnO. XRD analyses revealed single phase ZnO Wurtzite crystal structure. Photoluminescence (PL) spectra showed high-intensity in UV emission and very low intensity in the visible emission, which indicates a good surface morphology of the ZnO nanoparticles with little surface defects. Optical absorption spectra showed a blue shift by the capped ZnO due to the quantum confinement effect by the single crystal size of 5-6 nm as analysed by TEM. Capping effectiveness of each agent is discussed through possible capping mechanism and chemical reaction of each capping agent. This synthesis process is a low cost, high purity, easy to control method using only bio-compatible materials

  4. Influence of implant surface modification on integration with bone tissue

    OpenAIRE

    Kutsevlyak, V. I.; Starikova, S. L.; Starikov, V. V.; Mamalis, A. G.; Lavrynenko, S. N.; Ramsden, Jeremy J.

    2008-01-01

    Problems connected with the improvement of medical implant fixation in bone tissue are addressed by the formation of a highly developed surface and by the activation of the implant surface with an electret coating. The realization of such surface modifications is expedient for implants manufactured from tantalum or niobium or finished by coatings made from these metals, as they are chemically more inert than titanium. The techniques have been tested on animals followed by histo...

  5. Properties modification of nanopatterned surfaces functionalized with photo activated ligands

    OpenAIRE

    Stoianov, Stefan Vladimirov

    2011-01-01

    This dissertation focuses on four research topics: self-assembly of colloidal nanoparticles, surface modifications of the properties of ionically self-assembled multilayer films, surface enhanced Raman spectroscopy of functionalized gold nanoparticles, and two photon uncaging in gel. Those techniques are used for development of novel nanofabrication methods for top-down and bottom-up assembly of nanostructures, by modifying the properties of nanopatterned surfaces with photoactive ligands, an...

  6. Surface modification of sapphire for IR window application

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. [Tennessee Univ., Knoxville, TN (United States). Dept. of Materials Science and Engineering; Snyder, W.B. Jr. [Oak Ridge National Lab., TN (United States)

    1993-08-01

    Two surface modification techniques, a``super polish`` (SP), and ion implantation, were evaluated for improving the mechanical performance of sapphire IR window material. Both techniques increased the average strength as measured by 4-point bend tests and were effective in preventing the propagation of surface flaws. Ion implantation improved the reliability at lower stresses more than the SP. Neither process significantly affected the IR transmission. The SP produced a smoother surface as shown by optical scatter measurements.

  7. Nanotechnology for surface modification with polymer nanosheet assemblies

    International Nuclear Information System (INIS)

    This paper describes the recent topics on surface modification in confined area using polymer nano-sheet. Polymer nano-sheets consisting of amphiphilic poly (alkylacrylamide)s are described as ultrathin polymer langmuir-Blodgett films through two-dimensional hydrogen network between polymer backbones, which have been developed to assemble various functional molecules and nano materials such as metal and magnetic nanoparticles. Surface modification and nano coating using fluorinated polymer nano-sheets in confined area are given. Multicolored patterns based on structured color and photo patterning derived from nanostructures are demonstrated. The scopes of polymer nano-sheets concerning bottom-up soft nanodevice is introduced. (Author)

  8. Membrane potential and surface potential in mitochondria: uptake and binding of lipophilic cations.

    Science.gov (United States)

    Rottenberg, H

    1984-01-01

    The uptake and binding of the lipophilic cations ethidium+, tetraphenylphosphonium+ (TPP+), triphenylmethylphosphonium+ (TPMP+), and tetraphenylarsonium+ (TPA+) in rat liver mitochondria and submitochondrial particles were investigated. The effects of membrane potential, surface potentials and cation concentration on the uptake and binding were elucidated. The accumulation of these cations by mitochondria is described by an uptake and binding to the matrix face of the inner membrane in addition to the binding to the cytosolic face of the inner membrane. The apparent partition coefficients between the external medium and the cytosolic surface of the inner membrane (K'o) and the internal matrix volume and matrix face of the inner membrane (K'i) were determined and were utilized to estimate the membrane potential delta psi from the cation accumulation factor Rc according to the relation delta psi = RT/ZF ln [(RcVo - K'o)/(Vi + K'i)] where Vo and Vi are the volume of the external medium and the mitochondrial matrix, respectively, and Rc is the ratio of the cation content of the mitochondria and the medium. The values of delta psi estimated from this equation are in remarkably good agreement with those estimated from the distribution of 86Rb in the presence of valinomycin. The results are discussed in relation to studies in which the membrane potential in mitochondria and bacterial cells was estimated from the distribution of lipophilic cations. PMID:6492133

  9. 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...

  10. Impact of Dental Implant Surface Modifications on Osseointegration.

    Science.gov (United States)

    Smeets, Ralf; Stadlinger, Bernd; Schwarz, Frank; Beck-Broichsitter, Benedicta; Jung, Ole; Precht, Clarissa; Kloss, Frank; Gröbe, Alexander; Heiland, Max; Ebker, Tobias

    2016-01-01

    Objective. The aim of this paper is to review different surface modifications of dental implants and their effect on osseointegration. Common marketed as well as experimental surface modifications are discussed. Discussion. The major challenge for contemporary dental implantologists is to provide oral rehabilitation to patients with healthy bone conditions asking for rapid loading protocols or to patients with quantitatively or qualitatively compromised bone. These charging conditions require advances in implant surface design. The elucidation of bone healing physiology has driven investigators to engineer implant surfaces that closely mimic natural bone characteristics. This paper provides a comprehensive overview of surface modifications that beneficially alter the topography, hydrophilicity, and outer coating of dental implants in order to enhance osseointegration in healthy as well as in compromised bone. In the first part, this paper discusses dental implants that have been successfully used for a number of years focusing on sandblasting, acid-etching, and hydrophilic surface textures. Hereafter, new techniques like Discrete Crystalline Deposition, laser ablation, and surface coatings with proteins, drugs, or growth factors are presented. Conclusion. Major advancements have been made in developing novel surfaces of dental implants. These innovations set the stage for rehabilitating patients with high success and predictable survival rates even in challenging conditions. PMID:27478833

  11. Impact of Dental Implant Surface Modifications on Osseointegration

    Directory of Open Access Journals (Sweden)

    Ralf Smeets

    2016-01-01

    Full Text Available Objective. The aim of this paper is to review different surface modifications of dental implants and their effect on osseointegration. Common marketed as well as experimental surface modifications are discussed. Discussion. The major challenge for contemporary dental implantologists is to provide oral rehabilitation to patients with healthy bone conditions asking for rapid loading protocols or to patients with quantitatively or qualitatively compromised bone. These charging conditions require advances in implant surface design. The elucidation of bone healing physiology has driven investigators to engineer implant surfaces that closely mimic natural bone characteristics. This paper provides a comprehensive overview of surface modifications that beneficially alter the topography, hydrophilicity, and outer coating of dental implants in order to enhance osseointegration in healthy as well as in compromised bone. In the first part, this paper discusses dental implants that have been successfully used for a number of years focusing on sandblasting, acid-etching, and hydrophilic surface textures. Hereafter, new techniques like Discrete Crystalline Deposition, laser ablation, and surface coatings with proteins, drugs, or growth factors are presented. Conclusion. Major advancements have been made in developing novel surfaces of dental implants. These innovations set the stage for rehabilitating patients with high success and predictable survival rates even in challenging conditions.

  12. Effects of Surface Modification on the Dispersion Property of VGCF

    Institute of Scientific and Technical Information of China (English)

    FU Yaqin; HAN Chunshao; NI Qingqing

    2009-01-01

    In view of the easy agglomeration issue of vapor grown carbon fiber (VGCF) and the poor interfacial adhesion between VGCF and matrix resin, two-step surface modification with hydrogen peroxide and concentrated nitric acid was performed on VGCF. The surface structure and dispersion of VGCF before and after modification were tested and analyzed by XRD, TGA, FTIR, UV-visible spectrum and SEM. Moreover, VGCF/SMPU composites were prepared via a solution mixing method taking shape memory polyurethane (SMPU) as matrix, and the mechanical properties of the composites were also tested. The graphite crystal structure of VGCF showed very little change af-ter modification, the concentration of oxygen-containing functional groups on the surface of VGCF was visibly in-creased, and the dispersion and dispersion stability of VGCF in organic solvent were also clearly improved. In the cross section of the VGCF/SMPU composites, the dispersion of VGCF in matrix and the VGCF-matrix interfacial adhesion observed through SEM were both enhanced to a certain extent after surface modification. The two-step surface modified VGCF had more obvious mechanical reinforcement effects on the composites than that of the pris-tine VGCF.

  13. Surface modification of magnesium hydroxide using vinyltriethoxysilane by dry process

    Science.gov (United States)

    Lan, Shengjie; Li, Lijuan; Xu, Defang; Zhu, Donghai; Liu, Zhiqi; Nie, Feng

    2016-09-01

    In order to improve the compatibility between magnesium hydroxide (MH) and polymer matrix, the surface of MH was modified using vinyltriethoxysilane (VTES) by dry process and the interfacial interaction between MH and VTES was also studied. Zeta potential measurements implied that the MH particles had better dispersion and less aggregation after modification. Sedimentation tests showed that the surface of MH was transformed from hydrophilic to hydrophobic, and the dispersibility and the compatibility of MH particles significantly improved in the organic phase. Scanning electronic microscopy (SEM), Transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analyses showed that a thin layer had formed on the surface of the modified MH, but did not alter the material's crystalline phase. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectra (XPS) and Thermogravimetric analysis (TGA) showed that the VTES molecules bound strongly to the surface of MH after modification. Chemical bonds (Sisbnd Osbnd Mg) formed by the reaction between Si-OC2H5 and hydroxyl group of MH, also there have physical adsorption effect in the interface simultaneously. A modification mechanism of VTES on the MH surface by dry process was proposed, which different from the modification mechanism by wet process.

  14. Hydrophobically-associating cationic polymers as micro-bubble surface modifiers in dissolved air flotation for cyanobacteria cell separation.

    Science.gov (United States)

    Yap, R K L; Whittaker, M; Diao, M; Stuetz, R M; Jefferson, B; Bulmus, V; Peirson, W L; Nguyen, A V; Henderson, R K

    2014-09-15

    Dissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective cell removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, cell removals in excess of 90% were obtained, reaching a maximum of 99% cell removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations. PMID:24934266

  15. Wettability alteration by trimeric cationic surfactant at water-wet/oil-wet mica mineral surfaces

    International Nuclear Information System (INIS)

    The wettability of oil reservoir rock affects the efficiency of the oil recovery process by reducing the capillary force. Methyldodecylbis [2-(dimethyldodecylammonio) ethyl] ammonium tribromide is a trimeric cationic surfactant that contains three dodecyl chains and three quaternary ammonium head groups connected by divinyl groups. The surfactant was synthesized, purified and used as a new wetting alteration agent. This paper focuses on the ability of this trimeric cationic surfactant to alter the wettability of water-wet and oil-wet mica mineral surfaces. The contact angle data of the solid-liquid interface in oil/water/solid three-phase system show that the trimeric cationic surfactant, when compared with single- and double-chain cationic surfactant, is a more effective wetting agent for water-wet and oil-wet mica surfaces at lower concentration. Measurements by atomic force microscopy (AFM) show that the surfactant molecules have formed a monolayer to reverse the wetting properties. On the water-wet surface, the surface is suffused with negative charge, which could attract the cationic head of surfactant, and leave the hydrophobic tails exposed. In contrast, on the oil-wet surface, the hydrophobic tails were attracted by hydrophobic interactions to the oil film between the surfactant and the crude oil. The hydrophilic heads were left outside to form a hydrophilic layer, which could explain the wettable to hydrophilic trend. Alteration to the degree of wettability is mainly dependent on the adsorption areas of the surfactant. The data show that the ability of the trimeric cationic surfactant affect the wettability is independent of surface tension.

  16. Grafting modification on the surface of titanium dioxide by polystyrene

    Institute of Scientific and Technical Information of China (English)

    Wei Wu; Shouci Lu; Jianfeng Chen; Lei Shao; CheeKing Tan

    2003-01-01

    Based on the technology of titanium dioxide grafting modification with polystyrene (PS), the modification mechanisms are studied and the polystyrene-grafting states on the surface of titanium dioxide have been set up. Under the synergistic actions of mechanical force, chemistry and heat, macromolecular free radicals of PS are created, at the same time, the O-O bonds of titanium dioxide are broken and the oxide free radicals produced, and the numbers of oxygen atom are increased and crystal lattice defects rich electrons are formed on the surface of titanium dioxide. The radical polymerization is the main reaction between PS and titanium dioxide and C-O bonds form in the process of modification. Multi-sites chemical adsorption also exists besides grafting between PS and titanium dioxide.

  17. SURFACE-MODIFICATION OF FINE RED IRON OXIDE PIGMENT

    Institute of Scientific and Technical Information of China (English)

    Shuilin Zheng; Qinghui Zhang

    2003-01-01

    Surface-modification of fine red iron oxide pigment was carried out in an aqueous solution of sodium polyacrylate. The sedimentation time of modified samples in water increased from 1.05 to 264.4 hours while the particle size (d50) decreased from 1.09 to 0.85 μm, and the tinting strength increased from 100 to 115. The surface-modification as well as the dispersing and stabilizing mechanisms in aqueous solution of the samples were studied by means of IR,Thermal analysis and Zeta potential. The results showed that the modifier molecules acted on the surface of the particles by chemical and physical adsorption, and after the particles were dispersed in aqueous solution, endowing the particle surface with a relatively high negative Zeta potential, thus enhancing electrostatic and steric repulsion between particles for their effective stabilization.

  18. Synthesis and surface active properties of cationic surface active agents from crude rice bran oil

    Directory of Open Access Journals (Sweden)

    El-Dougdoug, W. I. A.

    1999-10-01

    Full Text Available Cationic surfactants of 2-hidroxy-3-(2- alkylamidopolyethyl amino propane-1-triethylammonium hydroxides (ix-xuia-d were prepared from fatty acids (ia-d [palmitic, stearic, oleic, linoleic acid] and mixed fatty acids of crude rice bran oil ie [RBO]. The reaction of these acids with ethylenediamine, diethylenetriamine, triethylenetetramine andletraethylenepentamine (iia-d produced (iii-viia-d. The produced amidopolyethylamine (iii-viia-d reacted with 2-epoxypropylenetriethylammonium chloride (viii to give the cationic surfactants (ix-xiiia-d . The produced derivatives were purified and characterized by microanalysis, molecular weight determination, infra-red (IR, and proton nuclear magnetic resonance (1H NMR spectra. The surface active properties and inhibition efficiency of the prepared cationic surfactants were determined.

    Se han preparado tensioactivos catiónicos de hidróxidos de! 2-hidroxi-3-(2-alquilamidopolietilamino propano-1;trietilamonio (ix-xiiia-d a partir de los ácidos grasos (ia-d [ácido palmítico, esteárico, oleico y linoleico] y mezclas de ácidos grasos de aceite de germen de arroz crudo ie [RBO]. La reacción de estos ácidos con etilenodiamina, dietilenotriamina, trietilenotetramina y tetraetilenopentamina (iia-d produjo los compuestos (iv-viia-d . Los amidopolietilaminos producidos (iii-viia-d reaccionaron con el cloruro de 2-epoxipropilenotrietilamonio (viii para dar los tensioactivos catiónicos (ix-xiiia-d. Los derivados producidos se purificaron y caracterizaron por microanálisis, determinación del peso molecular, espectros de infrarrojo (IR y resonancia magnética nuclear de protón (1H NMR. Se determinaron las propiedades tensioactivas y la eficacia de inhibición de los tensioactivos cati

  19. 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

  20. Adsorption of anionic and cationic polymers on porous and non-porous calcium carbonate surfaces

    Science.gov (United States)

    Bjorklund, Robert B.; Arwin, Hans; Järnström, Lars

    1994-01-01

    The adsorption of anionic and cationic polymers onto calcium carbonate surfaces was studied by ellipsometry. Sodium polyacrylate was observed to both adsorb on and promote dissolution of polished limestone surfaces in 5 mM CaSO 4 solution at pH 10.3. It was not possible to differentiate between the two processes when they occurred simultaneously. Cationic starch adsorbed on the limestone surfaces at low concentrations and caused mineral dissolution at higher concentrations. The adsorbed amount of starch was higher on surfaces which were first made porous by partial dissolution than on freshly polished surfaces. Surfaces created by cleavage of Iceland spar calcite were quite stable against dissolution and the amount of starch adsorbed determined by ellipsometry agreed well with the adsorbed mass determined from batch adsorption experiments on ground calcite.

  1. Development of Polymer Surface Modification Technology for Antistatic

    International Nuclear Information System (INIS)

    It is usually adoptive to mix a surface active agent or coat it on the surface of the film for antistatic of polymer sheets. But It is unable to make antistatic on the low humidity, especially not for packing electric materials such as IC, LSI, and industrial purpose. That's why deposition and coating metal or carbon on the surface of the film are adopted except the problems of the cost and transparency. On the area of styrene resin, the products that have functions of antistatic have been developing with ABS resin. Synthesised a great deal of electro-conductive elements on polymer, not only does the cost rise, but the properties of basic resin diminishes drastically. To stop these problems, it is possibly prospected to adopt the technology, which is able to produce antistatic polymer and use for industrial films, packing materials, and UV protection, to make motorcycle helmets and caps. Compared with functional Polymer, this Polymer is more environmentally friendly and has optical uniformity. Also, it has the properties on visibility. Therefore, it is expected to produce high value-added production. As the surface modification technology such as coating and ion implantation is improved, it will play an important role to make value-added products. As a result, the purpose of the study, applying the surface modification technology for industrial components and functioning product development, is to add surface conductivity on the products which limited for insulation properties among the existing products, develop the mass production technology for slashed costs and the valuation technology for surface modification technology, localize the production equipment to put to practical ion implantation for the low priced products, and develop the polymer surface modification technology for antistatic

  2. 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.

  3. Application of xenon difluoride for surface modification of polymers

    International Nuclear Information System (INIS)

    Chemical interaction between xenon difluoride (XeF2) 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

  4. Ion-Induced Surface Modification of Magnetically Operated Contacts

    OpenAIRE

    Karen Arushanov; Igor Zeltser; Sergey Karabanov; Rafail Maizels; Evgeny Moos; Alexander Tolstoguzov

    2012-01-01

    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.

  5. Surface modification of Zircaloy-4 substrates with nickel zirconium intermetallics

    International Nuclear Information System (INIS)

    Highlights: ► Oxidation performance of Zircaloy-4 tailored via NiZr intermetallic coating. ► Parametric design of experiments used to optimize surface modification approach. ► Microstructural evolution correlated with weight gain and hydrogen absorption. -- Abstract: Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel–zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370 °C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness

  6. Modification of Cu surface with picosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Vincenc Oboňa, J. [Materials innovation institute M2i, Department of Applied Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); Ocelík, V., E-mail: v.ocelik@rug.nl [Materials innovation institute M2i, Department of Applied Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Rao, J.C. [Materials innovation institute M2i, Department of Applied Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Skolski, J.Z.P.; Römer, G.R.B.E. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); Huis in ‘t Veld, A.J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); TNO Technical Sciences, Mechatronics, Mechanics and Materials, De Rondom 1, 5600 HE, Eindhoven (Netherlands); Hosson, J. Th. M. De [Materials innovation institute M2i, Department of Applied Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

    2014-06-01

    High purity, mirror-polished polycrystalline Cu surface was treated with single picosecond laser pulses at fluence levels close to the single-pulse modification threshold. The induced surface topography and sub-surface changes were examined with scanning and transmission electron microscopy, respectively. The analysis showed an increased absorption of laser energy on the microscopic surface topography inhomogeneities, even at a fluence level below the modification threshold. Many features, like spikes, bubbles, spheres, as well as small periodic ripples at the bottom of scratches, reveal a significant influence of melting and eruptive relaxation of the absorbed laser energy on the final appearance of the surface. Further, it was found that thermal stresses result in twinning to a depth of few tens of nanometers under the surface. Voids at this depth have been observed as well. The results of the observations provide new insights into the early stages of the picosecond laser pulse modification of metals, especially metals with a weak electron–phonon coupling.

  7. Improved LWR Cladding Performance by EPD Surface Modification Technique

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, Michael; Sridharan, Kumar

    2012-11-26

    This project will utilize the electro-phoretic deposition technique (EPD) in conjunction with nanofluids to deposit oxide coatings on prototypic zirconium alloy cladding surfaces. After demonstrating that this surface modification is reproducible and robust, the team will subject the modified surface to boiling and corrosion tests to characterize the improved nucleate boiling behavior and superior corrosion performance. The scope of work consists of the following three tasks: The first task will employ the EPD surface modification technique to coat the surface of a prototypic set of zirconium alloy cladding tube materials (e.g. Zircaloy and advanced alloys such as M5) with a micron-thick layer of zirconium oxide nanoparticles. The team will characterize the modified surface for uniformity using optical microscopy and scanning-electron microscopy, and for robustness using standard hardness measurements. After zirconium alloy cladding samples have been prepared and characterized using the EPD technique, the team will begin a set of boiling experiments to measure the heat transfer coefficient and critical heat flux (CHF) limit for each prepared sample and its control sample. This work will provide a relative comparison of the heat transfer performance for each alloy and the surface modification technique employed. As the boiling heat transfer experiments begin, the team will also begin corrosion tests for these zirconium alloy samples using a water corrosion test loop that can mimic light water reactor (LWR) operational environments. They will perform extended corrosion tests on the surface-modified zirconium alloy samples and control samples to examine the robustness of the modified surface, as well as the effect on surface oxidation

  8. Adsorption of Cationic Peptides to Solid Surfaces of Glass and Plastic

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2015-01-01

    peptides adsorb to solid surfaces of glass and plastic. Specifically, we use analytical HPLC to systematically quantify the adsorption of the three cationic membraneactive peptides mastoparan X, melittin, and magainin 2 to the walls of commonly used glass and plastic sample containers. Our results show...

  9. Rapid modification of montmorillonite with novel cationic Gemini surfactants and its adsorption for methyl orange

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bo [State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Food, South China University of Technology, Guangzhou 510640, Guangdong (China); Wang Xiaoying, E-mail: xyw@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Food, South China University of Technology, Guangzhou 510640, Guangdong (China); Yang Bin [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, Guangdong (China); Sun Runcang, E-mail: ynsun@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, School of Light Industry and Food, South China University of Technology, Guangzhou 510640, Guangdong (China); Institute of Biomass Chemistry and Technology, Beijing Forestry University, Beijing 100083 (China)

    2011-11-01

    Graphical abstract: A rapid method was developed to prepare organic montmorillonite (organo-MMT) using three novel Gemini surfactant by microwave irradiation of 1 h, which was more effective than conventional heating method of 8-48 h. The results showed that as the dosage and chain length of Gemini surfactants increased, the amount of the intercalary or adsorbed surfactant on the organoclay gradually increased, and the amount of methyl orange adsorbed onto the organo-MMTs also enhanced. Highlights: {yields} Rapid modifications of montmorillonite with Gemini surfactants were performed for 1 h. {yields} The amount of the surfactant on organoclay was examined by thermogravimetric analysis. {yields} Surfactant amount on the organoclay increased with increasing chain length and dosage. {yields} All organoclays displayed more excellent adsorption capacities on dye than clay. {yields} The adsorption capacity was positive to the amount and chain length of the surfactant. - Abstract: A rapid method was developed to prepare organic montmorillonite (organo-MMT) using three novel Gemini surfactants by microwave irradiation of 1 h, which was more effective than conventional heating method of 8-48 h. The structure and morphology of organo-MMTs were characterized by XRD, FT-IR, TEM and SEM. The adsorption amount of Gemini surfactants on MMT and the thermal stability of organo-MMTs were investigated by thermogravimetric analysis (TGA). The results indicated that Gemini surfactants were more efficient than cetyltrimethyl ammonium bromide in the modification of MMT, the organoclays obtained by microwave irradiation method had larger layer spacing than those from traditional heating method. And with the increase of the dosage and chain length of Gemini surfactants, the amount of the intercalary or adsorbed surfactant on the organoclay gradually increased, whereas the thermal stability weakened appropriately. Besides, the adsorption results for methyl orange indicated that all organo

  10. Experimental study on material surface modification of tool steel

    International Nuclear Information System (INIS)

    The author presents the surface temperature behavior of M42 high-speed tool steel samples during N+ implantation in an industrialized GLZ-100 metal-ion implantation machine. A detail study has been made on the parameters of N+ implantation. Optimized technical parameters have been presented. The microhardness of the sample surface implanted under these parameters has been increased by a factor of 2.3, and the wear-resistance has been improved by about 5.4 times. The research on the mechanism of surface modification of M42 steel by nitrogen ion implantation has also been made

  11. Experimental Study on Material Surface Modification of Tool Steel

    Institute of Scientific and Technical Information of China (English)

    沈丽如; 童洪辉; 王珂; 铁军; 孙爱萍

    2002-01-01

    This paper presents the surface temperature behavior of M42 high-speed tool steel samples during N+ implantation in an industrialized GLZ-100 metal-ion implantation machine. A detail study has been made on the parameters ofN+ implantation. Optimized technical parameters have been presented. The microhardness of the sample surface implanted under these parameters has been increased by a factor of 2.3, and the wear-resistance has been improved by about 5.4 times.The research on the mechanism of surface modification of M42 steel by nitrogen ion implantation has also been made.

  12. Design and Application of Surface Modification at Molecular Scale

    Institute of Scientific and Technical Information of China (English)

    CHEN Miao; XUE Qun-Ji; ZHOU Feng; GUAN Fei; LIU Wei-Min

    2004-01-01

    The structuring of surfaces on a nanoscale level-both chemically and topographically has become an increasingly relevant field of research in nanotechnology with widespread application potential in various fields of science ( e. g.surface engineering, electronics, biotechnology, optics). Two examples on surface modification at molecular scale with self-assembly monolayers are shown: ( 1 ) Chemically attaching ultra-thin polymer films through the self-assembly of silane fictionalized copolymer have been approved in this article. (2) The patterned films with microstructures on different substrates have been prepared through micro-contact printing technique and electro polymerization.

  13. Plasma technologies application for building materials surface modification

    Science.gov (United States)

    Volokitin, G. G.; Skripnikova, N. K.; Volokitin, O. G.; Shehovtzov, V. V.; Luchkin, A. G.; Kashapov, N. F.

    2016-01-01

    Low temperature arc plasma was used to process building surface materials, such as silicate brick, sand lime brick, concrete and wood. It was shown that building surface materials modification with low temperature plasma positively affects frost resistance, water permeability and chemical resistance with high adhesion strength. Short time plasma processing is rather economical than traditional processing thermic methods. Plasma processing makes wood surface uniquely waterproof and gives high operational properties, dimensional and geometrical stability. It also increases compression resistance and decreases inner tensions level in material.

  14. 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

  15. Improved chemical and electrochemical stability of perovskite oxides with less reducible cations at the surface.

    Science.gov (United States)

    Tsvetkov, Nikolai; Lu, Qiyang; Sun, Lixin; Crumlin, Ethan J; Yildiz, Bilge

    2016-09-01

    Segregation and phase separation of aliovalent dopants on perovskite oxide (ABO3) surfaces are detrimental to the performance of energy conversion systems such as solid oxide fuel/electrolysis cells and catalysts for thermochemical H2O and CO2 splitting. One key reason behind the instability of perovskite oxide surfaces is the electrostatic attraction of the negatively charged A-site dopants (for example, ) by the positively charged oxygen vacancies () enriched at the surface. Here we show that reducing the surface concentration improves the oxygen surface exchange kinetics and stability significantly, albeit contrary to the well-established understanding that surface oxygen vacancies facilitate reactions with O2 molecules. We take La0.8Sr0.2CoO3 (LSC) as a model perovskite oxide, and modify its surface with additive cations that are more and less reducible than Co on the B-site of LSC. By using ambient-pressure X-ray absorption and photoelectron spectroscopy, we proved that the dominant role of the less reducible cations is to suppress the enrichment and phase separation of Sr while reducing the concentration of and making the LSC more oxidized at its surface. Consequently, we found that these less reducible cations significantly improve stability, with up to 30 times faster oxygen exchange kinetics after 54 h in air at 530 °C achieved by Hf addition onto LSC. Finally, the results revealed a 'volcano' relation between the oxygen exchange kinetics and the oxygen vacancy formation enthalpy of the binary oxides of the additive cations. This volcano relation highlights the existence of an optimum surface oxygen vacancy concentration that balances the gain in oxygen exchange kinetics and the chemical stability loss. PMID:27295099

  16. Tribological effects of polymer surface modification through plastic deformation

    Indian Academy of Sciences (India)

    K O Low; K J Wong

    2011-12-01

    The efficacy of using polymers in cylindrical applications depends closely on its surface friction and wear characteristics. In this regard, a surface modification technique through plastic deformation has been implemented. Roller burnishing is commonly used to improve the surface quality of non-ferrous surfaces, but no work showed concern about roller burnishing as a polymer surface treatment process. The objective of the present work is to investigate the influence of burnishing force and burnishing speed on the friction and wear performance of acetal homopolymer and polyurethane under dry and lubricated sliding conditions. The results reveal that the coefficient of friction and wear rate decreased to a minimum value and then increased as higher burnishing force and speed were applied. It was shown that roller burnishing had favourable prospective to be utilized as a valuable polymer surface treatment technique.

  17. Some modifications of MPS method for incompressible free surface flow

    OpenAIRE

    Sun, Zhe; Djidjeli, K.; Xing, J. T.; Javed, A.

    2014-01-01

    As a Lagrangian mesh-free method, the Moving Particle Semi-implicit (MPS)[1] method is very suitable for simulating violent flows, such as breaking waves on free surface. However, despite its wide range of applicability, the original MPS algorithm suffers from some inherent difficulties in obtaining an accurate fluid pressure in both spatial and time domain. Different modifications to improve the method have been proposed [2-5] in the literature. In this paper, the authors developed a particl...

  18. Plasma modification of HEMA and EOEMA surface properties

    Czech Academy of Sciences Publication Activity Database

    Švorčík, V.; Kolářová, K.; Dvořánková, B.; Michálek, Jiří; Krumbholcová, Eva; Hnatowicz, Vladimír

    2006-01-01

    Roč. 161, č. 1 (2006), s. 15-19. ISSN 1042-0150 R&D Projects: GA ČR GA106/03/0514; GA AV ČR IAA5011301 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10480505 Keywords : polymer * plasma modification * surface properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.497, year: 2006

  19. Synthesis and surface modification of deagglomerated superparamagnetic nanoparticles

    OpenAIRE

    Lesniak, Christoph P.; Schiestel, Thomas; Nass, Rüdiger; Schmidt, Helmut K.

    1997-01-01

    A method for the preparation of aminosilane coated, chemically stable, agglomerate-free superparamagnetic iron oxide nanoparticles (ferrites, e.g. Fe3O4 and gamma-Fe2O3) has been developed. These nanocomposite particles posess core-shell structure. The well crystallized core particles are prepared by precipitation from aqueous salt solutions (primary particle size 10 nm). The surface modification of the weakly agglomerated core particles with aminiosilane (e.g. gamma-aminopropyl-triethoxysila...

  20. Surface chemical modification of fullerene by mechanochemical treatment

    International Nuclear Information System (INIS)

    In this study different encapsulating agents have been used for chemical modification of fullerenes. Fullerenes have reacted with tetrahydrofuran, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and ethylene vinyl acetate-ethylene vinyl versatate at room temperature under mechanical milling. The obtained powder has been dispersed in water by ultrasonication. The fullerene based colloids have been characterized by UV-vis, FTIR, Raman spectroscopy and atomic force microscopy. FTIR and Raman analysis have shown the presence of C60 after surface functionalization.

  1. Surface-Induced Modification of Supported Late Transition Metal Complexes

    OpenAIRE

    Snezhkova, Olesia

    2016-01-01

    The work presented in this thesis addresses the investigation of the electronic, magnetic, and structural properties of late transition metal complexes supported on various surfaces. The research is aimed at studying the interaction between the molecules and the support, together with the intermolecular interaction. This knowledge is essential e.g. for the development of organic molecule-based devices and the creation of active and stable catalysts. In this work, the modification of th...

  2. Surface modification of poly(dimethylsiloxane) for microfluidic assay applications

    International Nuclear Information System (INIS)

    The surface of a poly(dimethylsiloxane) (PDMS) film was imparted with patterned functionalities at the micron-scale level. Arrays of circles with diameters of 180 and 230 μm were functionalized using plasma oxidation coupled with aluminum deposition, followed by silanization with solutions of 3-aminopropyltrimethoxy silane (3-APTMS) and 3-mercaptopropyltrimethoxy silane (3-MPTMS), to obtain patterned amine and thiol functionalities, respectively. The modification of the samples was confirmed using X-ray photoelectron spectroscopy (XPS), gold nanoparticle adhesion coupled with optical microscopy, as well as by derivatization with fluorescent dyes. To further exploit the novel surface chemistry of the modified PDMS, samples with surface amine functionalities were used to develop a protein assay as well as an array capable of cellular capture and patterning. The modified substrate was shown to successfully selectively immobilize fluorescently labeled immunoglobulin G (IgG) by tethering Protein A to the surface, and, for the cellular arrays, C2C12 rat endothelial cells were captured. Finally, this novel method of patterning chemical functionalities onto PDMS has been incorporated into microfluidic channels. Finally, we demonstrate the in situ chemical modification of the protected PDMS oxidized surface within a microfluidic device. This emphasizes the potential of our method for applications involving micron-scale assays since the aluminum protective layer permits to functionalize the oxidized PDMS surface several weeks after plasma treatment simply after etching away the metallic thin film.

  3. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

    2012-01-01

    Efficiency of 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 ∼140 dB can reduce the thickness of a boundary gas layer between the plasma....... The ultrasonic irradiation during the plasma treatment consistently enhanced the treatment efficiency. The principal effect of ultrasonic irradiation can be attributed to enhancing surface oxidation during plasma treatment. In addition, ultrasonic irradiation can suppress arcing, and the uniformity of...... and the material surface, and thus, many reactive species generated in the plasma can reach the surface before they are inactivated and can be efficiently utilised for surface modification. In the present work, glass fibre reinforced polyester plates were treated using a dielectric barrier discharge...

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

    CERN Document Server

    Brown, A A

    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...

  5. A REVIEW OF OXYGEN-CONTAINING SURFACE GROUPS AND SURFACE MODIFICATION OF ACTIVATED CARBON

    Institute of Scientific and Technical Information of China (English)

    WU Yongwen; LI Zhong; XI Hongxia; XIA Qibin

    2004-01-01

    This review focused on the recent reports related to the function, characterization and modification of oxygen-containing surface groups of activated carbon (AC). The Oxygen-containing surface groups were briefly described, and the most frequently used techniques for characterization of the oxygen-containing surface groups on ACs were also briefly stated. A detailed discussion of the effects of the oxygen-containing surface groups on the adsorptive capacity of AC was given. The recent progresses in modification of the oxygen-containing surface groups of AC were also reviewed.

  6. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenjie [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Wang, Heyun [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832002 (China); Yang, Dazhi [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); An, Bo [Department of Orthopedics, Affiliated Hospital of Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Zhang, Wencheng [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

    2013-10-15

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P = 0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels. Highlights: • Electrospun nanofibrous scaffolds were successfully

  7. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification

    International Nuclear Information System (INIS)

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P = 0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels. Highlights: • Electrospun nanofibrous scaffolds were successfully

  8. Molecular modeling of organic corrosion inhibitors: why bare metal cations are not appropriate models of oxidized metal surfaces and solvated metal cations.

    Science.gov (United States)

    Kokalj, Anton

    2014-01-01

    The applicability of various models of oxidized metal surfaces - bare metal cations, clusters of various size, and extended (periodic) slabs - that are used in the field of quantum-chemical modeling of corrosion inhibitors is examined and discussed. As representative model systems imidazole inhibitor, MgO surface, and solvated Mg(2+) ion are considered by means of density-functional-theory calculations. Although the results of cluster models are prone to cluster size and shape effects, the clusters of moderate size seem useful at least for qualitative purposes. In contrast, the bare metal cations are useless not only as models of oxidized surfaces but also as models of solvated cations, because they bind molecules several times stronger than the more appropriate models. In particular, bare Mg(2+) binds imidazole by 5.9 eV, while the slab model of MgO(001) by only 0.35 eV. Such binding is even stronger for 3+ cations, e.g., bare Al(3+) binds imidazole by 17.9 eV. The reasons for these fantastically strong binding energies are discussed and it is shown that the strong bonding is predominantly due to electron charge transfer from molecule to metal cation, which stems from differences between molecular and metal ionization potentials. PMID:25125117

  9. Modification of polymeric substrates using surface-grafted nanoscaffolds

    Science.gov (United States)

    Thompson, Kimberlee Fay

    Surface grafting and modification of poly(acrylic acid) (PAA) were performed on nylon 6,6 carpet fibers to achieve permanent stain and soil resistance. PAA was grafted to nylon and modified with 1H, 1H-pentadecafluorooctyl amine (PDFOA) using an amidation agent, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM). The first goal was to optimize acrylamide modification of PAA in solution. Aqueous reactions with taurine, hydroxyethyl amine, and butyl amine progressed ˜100%, while PDFOA reactions in MeOH progressed ˜80%. Reaction products precipitated at 77% butyl or 52% PDFOA acrylamide contents. The second goal was to optimize the PAA grafting process. First, PAA was adsorbed onto nylon 6,6 films. Next, DMTMM initiated grafting of adsorbed PAA. PAA surface coverage was ˜78%, determined by contact angle analysis of the top 0.1--1 nm and x-ray photoelectron spectroscopy (XPS) analysis of the top 3--10 nm. The third goal was to modify PAA grafted nylon films with butyl amine and PDFOA. Randomly methylated beta-cyclodextrin (RAMEB) solubilized PDFOA in water. Contact angle detected ˜100% surface reaction for each amine, while XPS detected ˜77% butyl amine (H2O) and ˜50% for PDFOA (MeOH or H2O pH = 7) reactions. In H2O pH = 12, the PDFOA reaction progressed ˜89%, perhaps due to greater efficiency, access and solubility. The fourth goal was to perform surface depth profiling via angle-resolved XPS analysis (ARXPS). The PAA surface coverage from contact angle and XPS was confirmed. Further, adsorbed PAA was thicker than grafted PAA, supporting the theory that PAA adsorption occurs in thick layers onto nylon followed by DMTMM-activated spreading and grafting of thinner PAA layers across the surface. The PDFOA reaction in McOH produced a highly fluorinated but thin exterior and an unreacted PAA interior. The PDFOA reaction in H 2O pH = 12 produced a completely fluorinated exterior and highly fluorinated interior. Thus surface modification levels

  10. Surface modification of zinc-containing hydroxyapatite by tartaric acid

    Energy Technology Data Exchange (ETDEWEB)

    Turki, Thouraya; Othmani, Masseoud [Laboratoire de Physico-Chimie des Matériaux, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Bac, Christophe Goze [Laboratoire Charles Coulomb, UMR 5221 CNRS/UM2, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier (France); Rachdi, Férid, E-mail: Ferid.Rachdi@univ-montp2.fr [Laboratoire Charles Coulomb, UMR 5221 CNRS/UM2, Université Montpellier 2, Place E. Bataillon, 34095 Montpellier (France); Bouzouita, Khaled [Institut Préparatoire aux Etudes d’Ingénieur de Monastir (Tunisia)

    2013-11-01

    The surface of Zn-substituted hydroxyapatites (Ca{sub (10−x)}Zn{sub x}(PO{sub 4}){sub 6}(OH){sub 2}, with 0 ≤ x ≤ 2, Ca{sub x}Zn{sub x}HA) modified by tartaric acid was investigated by various techniques. XRD powder patterns revealed that synthesized samples were single phase of HA with broadened XRD reflections. FTIR and ({sup 13}C, {sup 1}H and {sup 31}P) MAS NMR measurements confirmed the grafting of the tartaric acid on the apatite surface. Chemical analysis showed that for ZnHA the grafted acid amount increases with the increase of the acid concentration in the starting solutions, while for HA, it remained constant, indicating more reactivity for ZnHA surface. A mechanism of surface modification is proposed based on the obtained results.

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

    International Nuclear Information System (INIS)

    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 SiO2/shape memory polyurethane (SiO2/SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO2/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

  12. 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.

  13. 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)

  14. Cationic modification and pigment exhaust dyeing of silk fabric%真丝织物阳离子改性及其涂料浸染工艺

    Institute of Scientific and Technical Information of China (English)

    关晋平; 陈国强; 于洋; 张梦甜; 付翰辉

    2012-01-01

    Cationic modification are carried out on silk fabric with cationic modifier S-PD01, and followed by pigment dyeing with pigment pink 118, The parameters of cationic modification and pigment dyeing are discussed. The optimum processes are modification at 70 ℃ for 40 min with S-PD01 7%(omf) and pH value 9-10, and exhaust dyeing at 60 ℃ for 30 min with pigment 6% (omf). The pigment dyeings of silk with cationic modification have obvious improved K/S value compared with those without modification. The color fastness of the dyeings are poor, but can be improved with fixation.%采用阳离子改性剂S-PD01对真丝织物进行阳离子改性处理,然后采用涂料桃红118染色,通过考察真丝阳离子化改性和染色的工艺参数,以优化工艺.优化的真丝改性工艺条件为:阳离子改性剂S-PD017%(omf),pH值9~10,70℃反应40min;涂料染色的优化工艺条件为:涂料6%(omf),60℃染色30min.结果表明,与未经阳离子处理的真丝织物涂料染色试样相比,改性试样染色K/S值显著提高.真丝织物涂料染色的牢度较差,经固色剂处理后有所改善.

  15. Tailored surface modification by ion implantation and laser treatment

    International Nuclear Information System (INIS)

    An important trend in materials science is the use of increasingly sophisticated methods to control composition and microstructure during processing. Near-surface modification by ion implantation and laser treatment is one of these new methods for tailoring material properties. Novel materials have been formed which are far from thermodynamic equilibrium and which exhibit unexpected and useful properties. The most extensively studied property changes include modified electrical properties of semiconductors and improved wear, hardness, and corrosion resistance of metals. The high degree of control available with energetic beams allows relations between microstructure and properties to be systematically investigated at the atomic level. This article illustrates how ion and laser beam modification is being applied to advance both the technology and the exploratory science of materials

  16. An Unusual Variation of Surface Tension with Concentration of.Mixed Cationic-anionic Surfactants

    Institute of Scientific and Technical Information of China (English)

    肖进新; 暴艳霞

    2001-01-01

    There are two platforms in the surface tension vs. concentration curve (γ-lgC curve) of cationic-anionic surfactant mixtures. The first platform is the same as that of common surfactant solution, and the cross point is the CMC. After the CMC, the mixtures form precipitate. At higher concentration, the mixtures form homogeneous sloution.When the mixtures form homogeneous solution at high concentration. surface tension increases with concentration, the becomes constant.So the γ-lgC curve exhibits the second platform. The surface tension at the second platform increases by increasing molar ratio of two surfactants and polar group size of surfactants, and decreases with adding inorganic salts.

  17. 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.

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

    Science.gov (United States)

    Singh, R. Arvind; Satyanarayana, N.; Sinha, Sujeet Kumar

    2011-12-01

    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.

  19. Surface modification on PMMA : PVDF polyblend: hardening under chemical environment

    Indian Academy of Sciences (India)

    R Bajpai; V Mishra; Pragyesh Agrawal; S C Datt

    2002-02-01

    The influence of chemical environment on polymers include the surface alteration as well as other deep modifications in surface layers. The surface hardening, as an effect of organic liquids on poly(methyl methacrylate): poly(vinylidene fluoride) (PMMA: PVDF), which is one of the few known miscible blends, has been detected using microhardness testing. Organic liquids like acetone, toluene, xylene and benzene were introduced on the surface of blend specimens for different durations. Vickers microhardness (v) was measured for treated and untreated specimens. The study reveals both hardening and plasticization of specimens at different exposure times. The degree of surface hardening is maximum under acetone treatment. All the specimens exhibit surface hardening at an exposure time of 1 h with all the four liquids. This feature is prominent with longer exposures for specimens with increasing content of PVDF. However, the degree of hardening decreases with the time of exposure in the respective environments. In general, acetone and toluene impart surface hardening, whereas, xylene and benzene soften the specimen. PMMA: PVDF (83 : 17) blend exhibits surface hardening under all the four treatments when compared with the respective untreated specimens.

  20. Surface Modification of Liposomal Vaccines by Peptide Conjugation

    Directory of Open Access Journals (Sweden)

    Hazra M2

    2011-01-01

    Full Text Available The aim of the present work was to prepare liposomal vaccine formulation by incorporating naked plasmid DNA that can trigger humoral and cell mediated protective immunity against infection. For these cationic lipids like dimyristoyl phosphatidylcholine (DMPC, dioleyl phosphatidyl ethanolamine (DOPE, [1, 2 – dioleyloxy -3-(trimethyl ammonium propane] (DOTAP, were taken in the ratio of 4:2:1 respectively. The liposomal formulations thus prepared were surface modified by peptide conjugation with the help of EDC and NHS. Physical characterization of liposomal formulationswas done by estimating the average size distribution, which gives an average liposomal size of 53.0nm. Concentration of peptide bound liposomes wasestimated by Lowry method which entails that bound protein concentration was 30.5 µg/ml.

  1. Ultraviolet curing for surface modification of textile fabrics.

    Science.gov (United States)

    Ferrero, Franco; Periolatto, Monica

    2011-10-01

    In this study, cotton, polyester and polyamide fabrics were treated by radical or cationic ultraviolet curing of different commercial products conferring water and oil repellency. Moreover, radical ultraviolet curing of chitosan was applied to confer antimicrobial properties. The advantages of this technology are well known making it very interesting for industrial applications: energy savings, low environmental impact, simple, cheap and small equipment, high treatment speed. The polymerization was controlled through weight gain and gel content measurements, while the properties of hydro and oil repellency were determined in terms of contact angle, moisture adsorption and water vapor permeability. The polymer distribution on fabric surfaces was investigated by scanning electron microscopy and atomic force microscopy. However the fabrics treated with chitosan were subjected to the standard test for determining the antimicrobial activity. Finally the finished cotton samples were subjected to washing fastness tests. PMID:22400240

  2. Surface modification of glass beads with glutaraldehyde: Characterization and their adsorption property for metal ions

    International Nuclear Information System (INIS)

    In this study, a new material that adsorbs the metal ions was prepared by modification of the glass beads surfaces with glutaraldehyde. First, the glass beads were etched with 4 M NaOH solution. Then, they were reacted with 3-aminopropyl-triethoxysilane (APTES). Finally, silanized glass beads were treated with 25% of glutaraldehyde solution. The characterization studies by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), elemental analysis and Scanning Electron Microscopy (SEM) indicated that modification of the glass bead surfaces was successfully performed. The adsorption studies exhibited that the modified glass beads could be efficiently used for the removal of the metal cations and anion (chromate ion) from aqueous solutions via chelation and ion-exchange mechanisms. For both Pb(II) and Cr(VI), selected as model ions, the adsorption equilibrium was achieved in 60 min and adsorption of both ions followed the second-order kinetic model. It was found that the sorption data was better represented by the Freundlich isotherm in comparison to the Langmuir and Redlich-Peterson isotherm models. The maximum adsorption capacities for Pb(II) and Cr(VI) were 9.947 and 11.571 mg/g, respectively. The regeneration studies also showed that modified glass beads could be re-used for the adsorption of Pb(II) and Cr(VI) from aqueous solutions over three cycles.

  3. Rational surface silane modification for immobilizing glucose oxidase.

    Science.gov (United States)

    Tian, Feibao; Guo, Yi; Lin, Feifei; Zhang, Yumei; Yuan, Qipeng; Liang, Hao

    2016-06-01

    Glucose oxidase (GOx) has many significant applications in biosensor and biocatalysis. In this study, we firstly quantitatively analyzed the binding efficiency of (3-aminopropyl) trimethoxysilane (APTES) modified onto the surface of GOx. It was found that the contents of the grafted silane did not significantly influence the relative activities and tertiary structures of all surface modified GOxs. Immobilization ratio and relative activity of all instances of APTES modified GOx increased, compared with those of native enzyme. However, good stability of immobilized GOx at extreme pH and high temperature could only be obtained when modified protein with low binding silane content. At pH 2.0, the immobilized GOx with low binding content showed a more than 600% activity, compared to the free enzyme. Therefore, rational surface modification would be beneficial to improving the activity and stability of immobilized enzyme as well as increasing loading amount. PMID:26921503

  4. Surface modification of multilayer graphene using Ga ion irradiation

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. 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.

  7. Plasma Processing of Large Curved Surfaces for SRF Cavity Modification

    CERN Document Server

    Upadhyay, J; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vušković, L

    2014-01-01

    Plasma based surface modification of niobium is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The development of the technology based on Cl2/Ar plasma etching has to address several crucial parameters which influence the etching rate and surface roughness, and eventually, determine cavity performance. This includes dependence of the process on the frequency of the RF generator, gas pressure, power level, the driven (inner) electrode configuration, and the chlorine concentration in the gas mixture during plasma processing. To demonstrate surface layer removal in the asymmetric non-planar geometry, we are using a simple cylindrical cavity with 8 ports symmetrically distributed over the cylinder. The ports are used for diagnosing the plasma parameters and as holders for the samples to be etched. The etching rate is highly correlated with the shape of the inner electrode, radio-frequency (RF) circuit elements, chlorine concentration in the Cl2/Ar gas mixtures, residence...

  8. 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

  9. Nonadiabatic nuclear dynamics of the ammonia cation studied by surface hopping classical trajectory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, Andrey K., E-mail: belyaev@herzen.spb.ru [Department of Theoretical Physics, Herzen University, St. Petersburg 191186 (Russian Federation); Domcke, Wolfgang, E-mail: wolfgang.domcke@ch.tum.de [Department Chemie, Technische Universität München, D-85747 Garching (Germany); Lasser, Caroline, E-mail: classer@ma.tum.de; Trigila, Giulio, E-mail: trigila@ma.tum.de [Zentrum Mathematik, Technische Universität München, D-85747 Garching (Germany)

    2015-03-14

    The Landau–Zener (LZ) type classical-trajectory surface-hopping algorithm is applied to the nonadiabatic nuclear dynamics of the ammonia cation after photoionization of the ground-state neutral molecule to the excited states of the cation. The algorithm employs a recently proposed formula for nonadiabatic LZ transition probabilities derived from the adiabatic potential energy surfaces. The evolution of the populations of the ground state and the two lowest excited adiabatic states is calculated up to 200 fs. The results agree well with quantum simulations available for the first 100 fs based on the same potential energy surfaces. Three different time scales are detected for the nuclear dynamics: Ultrafast Jahn–Teller dynamics between the excited states on a 5 fs time scale; fast transitions between the excited state and the ground state within a time scale of 20 fs; and relatively slow partial conversion of a first-excited-state population to the ground state within a time scale of 100 fs. Beyond 100 fs, the adiabatic electronic populations are nearly constant due to a dynamic equilibrium between the three states. The ultrafast nonradiative decay of the excited-state populations provides a qualitative explanation of the experimental evidence that the ammonia cation is nonfluorescent.

  10. The surface modification of diamond by ion implantation

    International Nuclear Information System (INIS)

    The surface modification of diamonds by ion implantation was studied by using Ar+, N2+, Zn+ and Cr+ ions. The surface layer of diamonds becomes conductive by ion implantation. The effect of ions implanted and the variation of crystal structure near surface were investigated. The ion implantation changes the color of the surface of diamonds to dark black and makes the surface layer amorphous. The distribution of implantet atoms in the surface layer was in good agreement with that estimated by the LSS theory, and the thickness of the amorphous layer was about 1.8 times of the depth of the maximum concentration. From this fact, the thickness of amorphous layer can be estimated from the LSS theory. The electric resistivity of the surface layer of diamonds decreased by the implantation of ions, and becomes a saturated value for the amount of implantation of 1 x 1016 ions/cm2. The saturated sheet resistivity was in inverse proportion to the thickness of amorphous layer. It was found that the resistivity of the produced amorphous layer was similar to that of the ordinary glassy carbon. The implanted metallic ions contributed to the electric conductivity of the matrix. The electro-chemical properties of ion-implanted diamonds were also studied. (Kato, T.)

  11. Surface modification of silica-coated zirconia by chemical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Lung, Christie Ying Kei, E-mail: yklung@graduate.hku.hk [Dental Materials Science, Faculty of Dentistry, University of Hong Kong (Hong Kong); Kukk, Edwin, E-mail: ekukk@utu.fi [Department of Physics and Astronomy, Faculty of Mathematics and Natural Sciences, University of Turku (Finland); Haegerth, Toni, E-mail: tjhage@utu.fi [Department of Physics and Astronomy, Faculty of Mathematics and Natural Sciences, University of Turku (Finland); Matinlinna, Jukka Pekka, E-mail: jpmat@hku.hk [Dental Materials Science, Faculty of Dentistry, University of Hong Kong (Hong Kong)

    2010-12-01

    Zirconia surface modification by various chemical treatments after silica coating by sandblasting was investigated in this study. The surface of silica-coated dental zirconia was hydroxylated by treatment with different acids at room temperature for 4 h, rinsed with deionized water and air-dried. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Shifts in binding energies for Zr 3d{sub 5/2} and Si 2p peaks were observed after treatment with acids, thereby showing a change in the chemical states of zirconium and silicon on the surface layer of silica-coated zirconia. The XPS analysis revealed that the silica-coated zirconia (SiO{sub 2}-ZrO{sub 2}) surfaces had changed to hydrous silica-coated zirconia (SiO{sub 2}-ZrO{sub 2}.nH{sub 2}O). One-way ANOVA analysis revealed there was significant difference in both surface roughness parameters of silica-coated zirconia after chemical treatments and the surface topography varied depending on the acid treatment.

  12. The Effects of Surface Modification on Spacecraft Charging Parameters

    Science.gov (United States)

    Evans, Amberly; Dennison, J. R.

    2010-10-01

    Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material's physical surface will change its reflection, transmission and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. An optical analysis of the effect of surface modification on spacecraft charging parameters on prototypical Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 microns in size. Using a UV/VIS/NIR light source and a diffraction grating spectrometer, measurements were performed on pristine and modified materials. The index of refraction and absorption coefficient were determined using the Fresnel Equations. The resulting absorption coefficient and Tauc plot were used to determine the energy of the band gap. The measured spectra confirmed that surface modification does induce changes in optical reflection, transmission, and absorption. The increased absorption observed results in increased photon energy deposited in the material, leading to increased charge emission through the photoelectric effect.

  13. 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

  14. Surface modification of polymer materials by excimer-laser irradiation

    International Nuclear Information System (INIS)

    The surface modification of fluoropolymers was studied with intense UV radiations from excimer lasers. The adhesive strength of polytetrafluoroethylene film was enhanced remarkably by KrF-laser irradiation in air when a small amount of aromatic compounds was blended. Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer was endowed with the high wettability by ArF-laser irradiation in water dissolved carbon monoxide. The enhancement of the wettability was closely related to the decrease of the fluorine/carbon atomic ratio and the increase of the oxygen/carbon ratio. (author)

  15. Application of EUV optics to surface modification of materials

    Czech Academy of Sciences Publication Activity Database

    Frolov, Oleksandr; Koláček, Karel; Štraus, Jaroslav; Schmidt, Jiří; Prukner, Václav; Choukourov, A.

    Vol. 8777. Bellingham, Washington: SPIE Press, 2013 - (Juha, L.; Bajt, S.; London, R.; Hudec, R.; Pína, L.), s. 877707-877707. (Proceedings of SPIE. 8777). ISBN 978-0-8194-9579-2. ISSN 0277-786X. [SPIE Optics + Optoelectronics :Damage to VUV, EUV, and X-ray Optics IV; and EUV and X-ray Optics: Synergy between Laboratory and Space III. Prague (CZ), 15.04.2013-18.04.2013] R&D Projects: GA MŠk(CZ) LG13029 Institutional support: RVO:61389021 Keywords : EUV * laser * radiation * source * capillary discharge * plasma * ablation * surface modification Subject RIV: BL - Plasma and Gas Discharge Physics

  16. Surface modification of yttria stabilized zirconia by ion implantation

    International Nuclear Information System (INIS)

    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 (400-10000C). 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

  17. Surface Modification on Acoustic Wave Biosensors for Enhanced Specificity

    Directory of Open Access Journals (Sweden)

    Nathan D. Gallant

    2012-09-01

    Full Text Available Changes in mass loading on the surface of acoustic biosensors result in output frequency shifts which provide precise measurements of analytes. Therefore, to detect a particular biomarker, the sensor delay path must be judiciously designed to maximize sensitivity and specificity. B-cell lymphoma 2 protein (Bcl-2 found in urine is under investigation as a biomarker for non-invasive early detection of ovarian cancer. In this study, surface chemistry and biofunctionalization approaches were evaluated for their effectiveness in presenting antibodies for Bcl-2 capture while minimizing non-specific protein adsorption. The optimal combination of sequentially adsorbing protein A/G, anti-Bcl-2 IgG and Pluronic F127 onto a hydrophobic surface provided the greatest signal-to-noise ratio and enabled the reliable detection of Bcl-2 concentrations below that previously identified for early stage ovarian cancer as characterized by a modified ELISA method. Finally, the optimal surface modification was applied to a prototype acoustic device and the frequency shift for a range of Bcl-2 concentration was quantified to demonstrate the effectiveness in surface acoustic wave (SAW-based detection applications. The surface functionalization approaches demonstrated here to specifically and sensitively detect Bcl-2 in a working ultrasonic MEMS biosensor prototype can easily be modified to detect additional biomarkers and enhance other acoustic biosensors.

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

    International Nuclear Information System (INIS)

    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)

  19. Surface assessment and modification of concrete using abrasive blasting

    Science.gov (United States)

    Millman, Lauren R.

    Composite systems are applied to concrete substrates to strengthen and extend the service life. Successful restoration or rehabilitation requires surface preparation prior to the application of the overlay. Surface coatings, waterproofing systems, and other external surface applications also require surface preparation prior to application. Abrasive blast media is often used to clean and uniformly roughen the substrate. The appropriate surface roughness is necessary to facilitate a strong bond between the existing substrate and overlay. Thus, surface modification using abrasive blast media (sand and dry ice), their respective environmental effects, surface roughness characterization prior to and after blasting, and the adhesion between the substrate and overlay are the focus of this dissertation. This dissertation is comprised of an introduction, a literature review, and four chapters, the first of which addresses the environmental effects due to abrasive blasting using sand, water, and dry ice. The assessment considered four response variables: carbon dioxide (CO2) emissions, fuel and energy consumption, and project duration. The results indicated that for sand blasting and water jetting, the primary factor contributing to environmental detriment was CO22 emissions from vehicular traffic near the construction site. The second chapter is an analysis of the International Concrete Repair Institute's (ICRI) concrete surface profiles (CSPs) using 3-D optical profilometry. The primary objective was to evaluate the suitability of approximating the 3-D surface (areal) parameters with those extracted from 2-D (linear) profiles. Four profile directions were considered: two diagonals, and lines parallel and transverse to the longitudinal direction of the mold. For any CSP mold, the estimation of the 3-D surface roughness using a 2-D linear profile resulted in underestimation and overestimation errors exceeding 50%, demonstrating the inadequacy of 2-D linear profiles to

  20. 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. PMID:24766528

  1. Surface modification of medical polyurethane by plasma treatment

    International Nuclear Information System (INIS)

    The wettability and surface structure of plasma treatment on medical polyurethane were studied. Two kinds of gas, N2, Ar, were used to create the low-temperature plasma under low pressure. The wettability was investigated by means of the sessile drop method using water, the results show that the contact angle of water decreases from 78.8 degree to 61.9 degree as the treatment time increases. The results of electron spectroscopy for chemical analysis indicate that original chemical bonds were broken up after plasma treatment, which was the main reason for the surface modification. At same time, the results of electron spinning resonance show that the amounts of radicals did not increase significantly after treatment, which is advantageous to clinical practice of polyurethane

  2. Modification of the surface of metals with multicomponent ion beams

    International Nuclear Information System (INIS)

    It is well known that a number of positive effects in the modification of the surface of materials by iron implantation results from the application of a set of ions of various elements. The total effect of the simultaneous action of multielement implantation is in many cases stronger than the effect of a single type of ions or consecutive implantation. Examination of the profiles of the implanted ions and of the element composition of the surface of the target, modified with the multicomponent beam, makes it possible to obtain information on the composition of the ion flux, generated by the composite cathode, and also on the characteristic special features of the variation of this flux when replacing individual component of the composition

  3. Biocompatible benzocyclobutene-based intracortical neural implant with surface modification

    Science.gov (United States)

    Lee, Keekeun; Massia, Stephen; He, Jiping

    2005-11-01

    This paper presents the fabrication of a benzocyclobutene (BCB) polymer-based intracortical neural implant for reliable and stable long-term implant function. BCB polymer has many attractive features for chronic implant application: flexibility, biocompatibility, low moisture uptake, low dielectric constant and easy surface modification. A 2 µm thick silicon backbone layer was attached underneath a flexible BCB electrode to improve mechanical stiffness. No insertion trauma was observed during penetrating into the dura of a rat. In vitro cytotoxicity tests of the completed BCB electrode revealed no toxic effects on cultured cells. The modified BCB surface with a dextran coating showed a significant reduction in 3T3 cell adhesion and spreading, indicating that this coating has the potential for lowering protein adsorption, minimizing inflammatory cell adhesion and glial scar formation in vivo, and thereby enhancing long-term implant performance.

  4. Hydrophilic surface modification of acrylate-based biomaterials.

    Science.gov (United States)

    Arnal-Pastor, M; Comín-Cebrián, S; Martínez-Ramos, C; Monleón Pradas, M; Vallés-Lluch, A

    2016-04-01

    Acrylic polymers have proved to be excellent with regard to cell adhesion, colonization and survival, in vitro and in vivo. Highly ordered and regular pore structures thereof can be produced with the help of polyamide templates, which are removed with nitric acid. This treatment converts a fraction of the ethyl acrylate side groups into acrylic acid, turning poly(ethyl acrylate) scaffolds into a more hydrophilic and pH-sensitive substrate, while its good biological performance remains intact. To quantify the extent of such a modification, and be able to characterize the degree of hydrophilicity of poly(ethyl acrylate), poly(ethyl acrylate) was treated with acid for different times (four, nine and 17 days), and compared with poly(acrylic acid) and a 90/10%wt. EA/AAc copolymer (P(EA-co-AAc)). The biological performance was also assessed for samples immersed in acid up to four days and the copolymer, and it was found that the incorporation of acidic units on the material surface was not prejudicial for cells. This surface modification of 3D porous hydrophobic scaffolds makes easier the wetting with culture medium and aqueous solutions in general, and thus represents an advantage in the manageability of the scaffolds. PMID:26767395

  5. Surface modification by ion implantation and ion beam mixing

    International Nuclear Information System (INIS)

    After its successful applications in the semiconductor industry, ion implantation is being employed for other technical applications. The main process in ion implantation is the introduction of additive elements to change the composition and properties of the surface region of a material. We present results demonstrating the important improvement of the wear resistance and friction in a NiTi alloy implanted with nitrogen. The formation of hard TiN precipitates embedded in an amorphous layer is responsible for such modifications. The generation of many atomic displacements in collision cascades during implantation can be also employed as a modification process itself. For instance, the chemical disordering in an implanted Fe60Al40 alloy induces a para- to ferromagnetic transition. The formation of an amorphous surface alloy by ion irradiation at a temperature of 15 K has been shown in Ni50Al50 by in situ RBS, channelling and TEM. The new method of dynamic ion mixing (DIM) combines ion bombardment with simultaneous material deposition and allows thicker adherent coatings to be built up, this is shown for both metallic Cu50Ni50 and ceramic TiB2 coatings. Recent results demonstrating a significant increase in fatigue lifetime of a coated 316 L stainless steel are also reported and discussed. (orig.)

  6. Effect of electrolytes on wettability of glass surface using anionic and cationic surfactant solutions.

    Science.gov (United States)

    Chaudhuri, Rajib Ghosh; Paria, Santanu

    2014-01-01

    Wetting behavior of a flat glass surface using pure nonionic, anionic, and cationic surfactants solutions has been studied by the dynamic contact angle (Wilhelmy plate) measurement technique. The advancing contact angle increases with the increasing concentration of surfactant and the value is maximum in the presence of cationic surfactant CTAB. The effect of different electrolytes in the presence of ionic surfactants was also studied to see the wetting behavior in the presence of electrolytes. The presence of electrolytes on ionic surfactant solutions significantly enhance the contact angle at very low concentration, which in turn lead to reduction in ionic surfactant requirement by more than 90% to achieve a particular contact angle. The effectiveness of electrolyte highly depends on the valance of counter ion. The reduction of ionic surfactant requirement is mostly useful for different applications such as flotation, and colloidal stability to reduce the production cost as well as environmental pollution. PMID:24183426

  7. The surface modification of stainless steel and the correlation between the surface properties and protein adsorption.

    Science.gov (United States)

    Kang, Chan-Koo; Lee, Yoon-Sik

    2007-07-01

    Protein adsorption on a biomaterial surface is of great importance as it usually induces unfavorable biological cascades, with the result that much surface modification research has had to be performed in an effort to prevent this. In this study, we developed surface modification methods for stainless steel, which is a representative metal for biomedical device. The stainless steels were first smoothened to different extents by electropolishing, in order to obtain a rough or smooth surface. On these two kinds of substrates, we introduced epoxide groups to the metal surface by silanization with 3-glycidoxypropyltrimethoxysilane (GPTS). Then, various polymers such as poly(ethylene glycol) (PEG), poly(tetrahydrofuran glycol) (PTG), poly(propylene glycol) (PPG) and poly(dimethylsiloxane) (PDMS) were grafted on the silanized stainless steels. Each surface modification step was confirmed by various analytical methods. Contact angle measurement revealed that the surface hydrophilicity was controllable by polymer grafting. Root-mean-square (RMS) data of atomic force microscopy showed that surface roughness was dramatically changed by electropolishing. Based on these results, the correlation between surface properties and protein adsorption was investigated. In the protein adsorption study, we observed that all of the polymer-grafted stainless steels exhibited lower protein adsorption, when compared with bare stainless steel. Moreover, a hydrophilic and smooth surface was found to be the best of choice for decreasing the protein adsorption. PMID:17277988

  8. Arsenic and major cation hydrogeochemistry of the Central Victorian (Australia) surface waters.

    Science.gov (United States)

    Sultan, Khawar; Dowling, Kim

    2006-01-01

    This paper reports on the major cations (Ca, Mg, Na and K) and arsenic (As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4), oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386 microS/cm). The concentrations of dissolved major cations in surface waters were found to be in the order of Na>Mg>Ca>K and in soils the contents of metals followed an order of abundance as: Ca>Mg>K>Na. While Na was the least abundant in soils, it registered the highest dissolved cation in surface waters. Of the four major cations, the average concentration of Na (98.7 mg/L) was attributed to the weathering of feldspars and atmospheric input. Relatively highly dissolved concentrations of Na and Mg compared with the world average values of rivers reflected the weathering of rock and soil minerals within the catchments. The As soil level is naturally high (linked to lithology) as reflected by high background soil values and mining operations are also considered to be a contributory factor. Under relatively alkaline-oxidative conditions low mobility of dissolved As (average about 7.9 microg/L) was observed in most of the surface waters with a few higher values (> 15 microg/L) around a sewage disposal site and mine tailings. Arsenic in soils is slowly released into water under alkaline and/or lower Eh conditions. The efficient sink of Fe, Al and Mn oxides acts as a barrier against the As release under near neutral-oxidising conditions. High As content (average about 28.3 mg/kg) in soils was found to be associated with Fe-hydroxides as revealed by XRD and SEM analysis. The dissolved As concentration was found to be below the recommended maximum levels for recreational water in all surface waters (lakes and rivers) in the study area. Catchment lithology exerted the fundamental control on surface

  9. Arsenic and major cation hydrogeochemistry of the Central Victorian (Australia) surface waters

    Institute of Scientific and Technical Information of China (English)

    Khawar SULTAN; Kim DOWLING

    2006-01-01

    This paper reports on the major cations(Ca, Mg, Na and K) and arsenic(As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4),oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386 μS/cm). The concen- trations of dissolved major cations in surface waters were found to be in the order of Na>>Mg>Ca>K and in soils the contents of metals followed an order of abundance as: Ca>Mg>>K>Na. While Na was the least abundant in soils, it registered the highest dissolved cation in surface waters. Of the four major cations, the average concentration ofNa(98.7 mg/L) was attributed to the weathering of feldspars and atmospheric input. Relatively highly dissolved concentrations of Na and Mg compared with the world average values of rivers reflected the weathering of rock and soil minerals within the catchments.The As soil level is naturally high(linked to lithology) as reflected by high background soil values and mining operations are also considered to be a contributory factor. Under relatively alkaline-oxidative conditions low mobility of dissolved As (average about 7.9 μg/L) was observed in most of the surface waters with a few higher values(>15 μg/L) around a sewage disposal site and mine tailings.Arsenic in soils is slowly released into water under alkaline and/or lower Eh conditions. The efficient sink of Fe, Al and Mn oxides acts as a barrier against the As release under near neutral-oxidising conditions. High As content (average about 28.3 mg/kg) in soils was found to be associated with Fe-hydroxides as revealed by XRD and SEM analysis. The dissolved As concentration was found to be below the recommended maximum levels for recreational water in all surface waters(lakes and rivers) in the study area. Catchment lithology exerted the fundamental control on surface water chemistry

  10. Atmospheric Microplasma Application for Surface Modification of Biomaterials

    Science.gov (United States)

    Shimizu, Kazuo; Fukunaga, Hodaka; Tatematsu, Shigeki; Blajan, Marius

    2012-11-01

    Atmospheric microplasma has been intensively studied for applications in various fields, since in this technology the generated field is only 1 kV (approx) under atmospheric pressure and a dielectric barrier discharge gap of 10 to 100 µm. A low discharge voltage atmospheric plasma process is an economical and effective solution for various applications such as indoor air control including sterilization, odor removal, and surface treatment, and would be suitable for medical applications in the field of plasma life sciences. In this paper, we present the application of microplasma for the surface treatment of materials used in medical fields. Moreover, a biomaterial composed of L-lactic acid is used in experiments, which can be biodecomposed in the human body after medical operations. The surface modification process was carried out with active species generated between the microplasma electrodes, which were observed by emission spectrometry. Microplasma treatment of a polymer sheet using Ar as the process gas decreased the contact angle of a water droplet at the surface of the polymer from 78.3 to 45.6° in 10 s, indicating improved surface adhesive characteristics.

  11. Layer by Layer, Nano-particle "Only" Surface Modification of Filtration Membranes

    Science.gov (United States)

    Escobar-Ferrand, Luis

    Layer by Layer (LbL) deposition using primarily inorganic silica nanoparticles is employed for the modification of polymeric micro and ultrafiltration (MF/UF) membranes to produce thin film composites (TFC) with potential nanofiltration (NF) and reverse osmosis (RO) capabilities.. A variety of porous substrate membranes with different membrane surface characteristics are employed, but exhibiting in common that wicking of water does not readily occur into the pore structure, including polycarbonate track etched (PCTE), polyethersulfone (PES) and sulfonated PES (SPEES) MF/UF membranes. Both spherical (cationic/anionic) and eccentric elongated (anionic) silica nanoparticles are deposited using conditions similar to those reported by Lee et al. Appropriate selection of the pH's for anionic and cationic particle deposition enables the construction of nanoparticle only layers 100--1200 nm in thickness atop the original membrane substrates. The surface layer thickness varies monotonically with the number of bilayers (anionic/cationic deposition cycles) as expected. The deposition process is optimized to eliminate drying induced cracking and to improve mechanical durability via thickness control and post-deposition hydro-thermal treatment. The hydrodynamic permeability of these TFC membranes is measured to evaluate their performance under typical NF operating conditions using dead-end permeation experiments and their performance compared quantitatively with realistic hydrodynamic models, with favorable results. For track etched polycarbonate MF substrates, surface modification causes a permeability reduction of approximately two orders of magnitude with respect to the bare substrates, to values comparable to those for typical commercial NF membranes. Good quantitative agreement with hydrodynamic models with no adjustable parameters was also established for this case, providing indirect confirmation that the LbL deposited surface layers are largely defect (crack) free

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

    OpenAIRE

    Norhan Nady

    2016-01-01

    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 ...

  13. Electrochemical behavior of Ni-Ti alloy after surface modification

    Directory of Open Access Journals (Sweden)

    M. Kaczmarek

    2006-08-01

    Full Text Available Purpose: The shape memory effect and superelasticity make the nickel-titanium alloy an interesting material formedical applications. But the biocompatibility has been questioned due to conflicting results in the literature.The latest research has shown that this situation may be caused by a variation in NiTi surface treatment.The appropriate surface treatment increases the corrosion resistance. The paper presents the electrochemicalbehavior of NiTi alloy after surface modification with the use of various techniques.Design/methodology/approach: The evaluation of the electrochemical behavior of NiTi alloy was realizedboth by recording of anodic polarization curves with the use of the potentiodynamic method and by anelectrochemical impedance spectroscopy technique (EIS.Findings: Surface condition of metallic biomaterial determines its corrosion resistance. In the course of thework it was observed that the lowest values of corrosion current were recorded for the sterilized and thethermally passivated samples. The highest values of corrosion current were recorded for the ground samples.These samples obviously had also the highest corrosion rate.Research limitations/implications: The obtained results are the basis for the optimization of physicochemicalproperties of the metallic biomaterial. The future research should be focused on selected specific implantsspecially with respect to their application features.Practical implications: On the basis of the obtained results it can be stated that the suggested surface treatmentcan be applicable for medical implants due to the increase of the corrosion resistance and in consequence theincrease of biocompatibility.Originality/value: The paper presents the influence of various methods of the surface treatment on corrosionresistance of the NiTi alloy. The suggested methods can be applied in treatment of the material intended formedical applications especially in cases where the surface roughness plays important

  14. 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.

  15. Adsorption of reovirus to clay minerals: effects of cation-exchange capacity, cation saturation, and surface area.

    OpenAIRE

    Lipson, S M; Stotzky, G

    1983-01-01

    The adsorption of reovirus to clay minerals has been reported by several investigators, but the mechanisms defining this association have been studied only minimally. The purpose of this investigation was to elucidate the mechanisms involved with this interaction. More reovirus type 3 was adsorbed, in both distilled and synthetic estuarine water, by low concentrations of montmorillonite than by comparable concentrations of kaolinite containing a mixed complement of cations on the exchange com...

  16. Surface modification of multiwall carbon nanotubes by sulfonitric treatment

    Science.gov (United States)

    Gómez, Sofía; Rendtorff, Nicolás M.; Aglietti, Esteban F.; Sakka, Yoshio; Suárez, Gustavo

    2016-08-01

    Carbon nanotubes are widely used for electronic, mechanical, and optical devices due to their unique structural and quantum characteristics. The species generated by oxidation on the surface of these materials permit binding new reaction chains, which improves the dispersibility, processing and compatibility with other materials. Even though different acid treatments and applications of these CNT have been reported, relatively few research studies have focused on the relationship between the acid treatment and the formation of nanodefects, specific oxidized species or CNT surface defects. In this work, multiwall carbon nanotube (MWCNT) oxidation at 90 °C was characterized in order to determine the acid treatment effect on the surface. It was found that oxidized species are already present in MWCNT without an acid treatment, but there are not enough to cause water-based dispersion. The species were identified and quantified by infrared spectroscopy and X-ray photoelectron spectroscopy. Also, transmission electron microscopy observations showed not only modifications of the oxidized species, but also morphological damage on the surfaces of MWCNT after being subjected to the acid treatment. This effect was also confirmed by Raman spectroscopy. The acid treatment generates higher oxidized species, decreasing the zeta potential in the whole pH range.

  17. Ion irradiation induced surface modification studies of polymers using Spmb

    International Nuclear Information System (INIS)

    Various types of scanning probe microscopy (SPM) techniques: atomic force microscopy (AFM) (contact and tapping in height and amplitude mode), scanning tunnelling microscopy (STM) and conducting atomic force microscopy (C-AFM) are used for studying ion beam induced surface modifications, nanostructure/cluster formation and disintegration in polymers and similar soft carbon based materials. In the present study, the results of studies on four materials, namely (A) methyltriethoxysilane/phenyltriethoxysilane (MTES/PTES) based gel, (B) triethoxisilane (TH) based gel, (C) highly oriented pyrolytic graphite (HOPG) bulk and (D) fullerene (C60) thin films are discussed. In the case of Si based gels prepared from pre-cursors containing organic groups (MTES/PTES), hillocks are observed at the surface and their size decreases from 70 to 25 nm with increasing fluence, whereas, in the case of a gel with a stoichiometry SiO1.25H1, prepared from TH, an increases in the size of hillocks is observed. Hillocks are also formed at the surface of HOPG irradiated with 120 MeV Au beam at a low fluence, whereas, formation of craters and a re-organisation of surface features is observed at a higher fluence. In the case of C60 films, 120 MeV Au ion irradiation induces the formation of conducting ion tracks, which is attributed to the transformation from insulating C60 to conducting graphite like carbon

  18. Adsorption of cationic peptides to solid surfaces of glass and plastic.

    Directory of Open Access Journals (Sweden)

    Kasper Kristensen

    Full Text Available Cationic membrane-active peptides have been studied for years in the hope of developing them into novel types of therapeutics. In this article, we investigate an effect that might have significant experimental implications for investigators who wish to study these peptides, namely, that the peptides adsorb to solid surfaces of glass and plastic. Specifically, we use analytical HPLC to systematically quantify the adsorption of the three cationic membrane-active peptides mastoparan X, melittin, and magainin 2 to the walls of commonly used glass and plastic sample containers. Our results show that, at typical experimental peptide concentrations, 90% or more of the peptides might be lost from solution due to rapid adsorption to the walls of the sample containers. Thus, our results emphasize that investigators should always keep these adsorption effects in mind when designing and interpreting experiments on cationic membrane-active peptides. We conclude the article by discussing different strategies for reducing the experimental impact of these adsorption effects.

  19. From solution to oxide. Cations condensation in aqueous solution. Surface chemistry of oxides

    International Nuclear Information System (INIS)

    How is formed a solid from a solution? What are the properties of a dispersion of particles? The aim of this book is to answer to these questions. From an overview of the condensation processes of the cations in aqueous solution and the revealing of the structural relationships between species in solution and the formed solids, this book gives a logic in the phenomenon of oxides precipitation. The relationship that is established between the solutions chemistry and the solid chemistry allows to rationalize the behaviour of cations and to discuss the various factors whose structure, morphology and particles size are depending. It is from basic concepts relative to the oxide - aqueous solution interface that is presented the surface chemistry of oxides nano-particles. This one establishes the properties and the behaviour of the dispersions. Different phenomena bound to adsorption (arranged aggregation, control of particles size, interfacial electronic transfer, magnetic interactions between particles...) are studied. This book develops some aspects of the chemistry of metallic cations which is very important in a fundamental and technological point of view (synthesis of nano-materials, ceramics powders, catalysts, geochemical processes, biological phenomena, sol-gel techniques...). It is intended for university or engineers students and industrial searchers. (O.M.)

  20. Ion beam applications in surface and bulk modification of insulators

    International Nuclear Information System (INIS)

    The development of new materials is driven by the high impact of such materials in important areas such as information technology, energy management, environmental protection, and human health. Most of these applications require devices having surface layers and thin film coatings or appropriately doped matrices with dedicated properties and structure. For many applications such accurately configured structures cannot be achieved by thermal diffusion methods. Ion beam methods, on the other hand, offer accurate control of implanted ion/dopant species, and implantation fluence, profile and temperature. They can be used to grow nanocomposite materials by ion beam deposition, to create nano-patterned surfaces of materials by ion beam erosion, to introduce impurities into matrices by ion implantation, or to investigate novel properties resulting from impurity?defect interactions. Ion beam modification of materials may be achieved by ion implantation or ion irradiation. These are unique approaches to altering the near surface region of a wide range of solid materials in a manner that is independent of many of the constraints associated with conventional processing methods. Some materials, such as metals and most semiconductors, are rather insensitive to the electronic part of the energy deposition as long as the electronic stopping power remains below a certain critical threshold value. Other materials, for example insulating and dielectric materials such as ionic solids, alkali and silver halides, dielectric glasses and amorphous materials, are quite sensitive to the energy deposited in their electronic systems. The high sensitivity of these materials to ion irradiation makes them particularly attractive for ion beam modification. A comprehensive programme on ion beam modification requires not only facilities for materials production and ion beam implantation/irradiation, but also modern methods of analysis and diagnostics in order to characterize the ion beam induced

  1. Modification of polyamide-CdS-CdSe composite material films with Ag using a cation–cation exchange reaction

    International Nuclear Information System (INIS)

    Highlights: • We investigated deposition of a mixed CdSe-CdS-Ag2Se-Ag2S on polyamide. • A single chalcogen precursor – K2SeS2O6 – was used. • AAS showed five- to ten-fold excess of chalcogens diffused into PA. • Addition of AgNO3 resulted in subsurface Ag2Se–Ag2S formation. - Abstract: Thin mixed CdSe-CdS-Ag2Se-Ag2S films were deposited on a polyamide 6 (PA) surface by successfully using a cation-exchange reaction between Cd2+ and Ag+ to convert CdSe-CdS into Ag2Se-Ag2S. These were deposited using a K2SeS2O6 precursor solution at 60 °C followed by cadmium acetate (Cd(CH3COO)2). An aqueous AgNO3 solution was used as the Ag source. XRD patterns showed a complex PA-Cd-S-Se-Ag film crystalline composition with CdS, CdSe, Ag2S and Ag2Se peaks. Calculated dislocation density ranged within 5–15 × 1013 lines·m−2 indicating high quality atomic layers. Atomic Absorption Spectroscopy (AAS) showed five- to ten-fold excess of chalcogens to metals in the thin films formed. No chalcogenides were observed on the sample surface during XPS analysis after Ag exchange due to the desorption of CdS and CdSe layers, not diffused into the bulk of the polymer suggesting that silver chalcogenides were located subsurface, as opposed to the outermost layer, likely comprised of Ag2O

  2. Modification of polyamide-CdS-CdSe composite material films with Ag using a cation–cation exchange reaction

    Energy Technology Data Exchange (ETDEWEB)

    Krylova, V.; Žalenkienė, S.; Dukstienė, N. [Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu st. 19, LT-50254, Kaunas (Lithuania); Baltrusaitis, J., E-mail: job314@lehigh.edu [Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 (United States)

    2015-10-01

    Highlights: • We investigated deposition of a mixed CdSe-CdS-Ag{sub 2}Se-Ag{sub 2}S on polyamide. • A single chalcogen precursor – K{sub 2}SeS{sub 2}O{sub 6} – was used. • AAS showed five- to ten-fold excess of chalcogens diffused into PA. • Addition of AgNO{sub 3} resulted in subsurface Ag{sub 2}Se–Ag{sub 2}S formation. - Abstract: Thin mixed CdSe-CdS-Ag{sub 2}Se-Ag{sub 2}S films were deposited on a polyamide 6 (PA) surface by successfully using a cation-exchange reaction between Cd{sup 2+} and Ag{sup +} to convert CdSe-CdS into Ag{sub 2}Se-Ag{sub 2}S. These were deposited using a K{sub 2}SeS{sub 2}O{sub 6} precursor solution at 60 °C followed by cadmium acetate (Cd(CH{sub 3}COO){sub 2}). An aqueous AgNO{sub 3} solution was used as the Ag source. XRD patterns showed a complex PA-Cd-S-Se-Ag film crystalline composition with CdS, CdSe, Ag{sub 2}S and Ag{sub 2}Se peaks. Calculated dislocation density ranged within 5–15 × 10{sup 13} lines·m{sup −2} indicating high quality atomic layers. Atomic Absorption Spectroscopy (AAS) showed five- to ten-fold excess of chalcogens to metals in the thin films formed. No chalcogenides were observed on the sample surface during XPS analysis after Ag exchange due to the desorption of CdS and CdSe layers, not diffused into the bulk of the polymer suggesting that silver chalcogenides were located subsurface, as opposed to the outermost layer, likely comprised of Ag{sub 2}O.

  3. Nanoscale Surface Modification of Lithium-Rich Layered-Oxide Composite Cathodes for Suppressing Voltage Fade.

    Science.gov (United States)

    Zheng, Fenghua; Yang, Chenghao; Xiong, Xunhui; Xiong, Jiawen; Hu, Renzong; Chen, Yu; Liu, Meilin

    2015-10-26

    Lithium-rich layered oxides are promising cathode materials for lithium-ion batteries and exhibit a high reversible capacity exceeding 250 mAh g(-1) . However, voltage fade is the major problem that needs to be overcome before they can find practical applications. Here, Li1.2 Mn0.54 Ni0.13 Co0.13 O2 (LLMO) oxides are subjected to nanoscale LiFePO4 (LFP) surface modification. The resulting materials combine the advantages of both bulk doping and surface coating as the LLMO crystal structure is stabilized through cationic doping, and the LLMO cathode materials are protected from corrosion induced by organic electrolytes. An LLMO cathode modified with 5 wt % LFP (LLMO-LFP5) demonstrated suppressed voltage fade and a discharge capacity of 282.8 mAh g(-1) at 0.1 C with a capacity retention of 98.1 % after 120 cycles. Moreover, the nanoscale LFP layers incorporated into the LLMO surfaces can effectively maintain the lithium-ion and charge transport channels, and the LLMO-LFP5 cathode demonstrated an excellent rate capacity. PMID:26335589

  4. The influence of clay surface modification with berberine on the sorption of anthocyanins

    Science.gov (United States)

    Chulkov, A. N.; Deineka, V. I.; Tikhova, A. A.; Vesentzev, A. I.; Deineka, L. A.

    2012-03-01

    The influence of preliminary sorption of berberine on the sorption of anthocyanins by bentonite clay was studied. The cation exchange sorption mechanism was found to be replaced by hydrophobic sorption of these compounds after clay modification with berberine. The enthalpy of sorption along the initial isotherm part changed from endothermic to exothermic.

  5. Effect of cotton fabric cationic modification on pigment dyeing%阳离子改性对棉织物涂料染色的影响

    Institute of Scientific and Technical Information of China (English)

    朱凯棋; 杨杏; 李美真

    2016-01-01

    采用阳离子改性剂对棉织物改性,然后进行涂料染色和固色处理,筛选出合适的阳离子改性剂Fix-800,并讨论了改性剂用量、温度、时间和氢氧化钠用量对棉织物涂料染色的K/S值、匀染性、染色牢度的影响,确定最佳改性工艺。结果表明,在65℃的改性条件下,使用3%(omf)的阳离子改性剂Fix-800,对棉织物改性30 min后染色,织物K/S值明显提高。%The cotton fabric is modified with cationic modifying agent followed by pigment dyeing and fixation treatment. The Fix-800 is screened as the suitable modification agent. And the effects of modification agent dosage, modification time, temperature and sodium hydroxide concentration onK/S value, levelling property and color fastness of pigment dyed cotton fabric are discussed. The optimum modification process is determined as following: modifying agent Fix-800 3%(omf), modification time 30 min. TheK/S value of dyed fabric after modification increases significantly.

  6. Surface modification of phyllosilicate minerals by fluorination methods

    International Nuclear Information System (INIS)

    The effect of fluorination on various types of phyllosilicate minerals has been investigated. Two different fluorination techniques have been used: direct F2 gas and cold radio frequency plasma involving c-C4F8 or O2/CF4 mixtures. The modifications of the surface composition and properties have been followed mostly by x-ray photoelectron spectroscopy (XPS). Depending of the fluorination reagents, a reactive etching process involving M-F bonding occurs (direct F2 gas; O2-CF4 rf plasma) or a carbon fluoride deposition takes place (c-C4F8 rf plasma). In the case of F2-gas treated minerals, Si 2p XPS signal accounts for the presence of fluorinated Si environments.

  7. Nonadiabatic nuclear dynamics of the ammonia cation studied by surface hopping classical trajectory calculations

    CERN Document Server

    Belyaev, Andrey K; Lasser, Caroline; Trigila, Giulio

    2014-01-01

    The Landau--Zener (LZ) type classical-trajectory surface-hopping algorithm is applied to the nonadiabatic nuclear dynamics of the ammonia cation after photoionization of the ground-state neutral molecule to the excited states of the cation. The algorithm employs the recently proposed formula for nonadiabatic LZ transition probabilities derived from the adiabatic potential energy surfaces. The evolution of the populations of the ground state and the two lowest excited adiabatic states is calculated up to 200 fs. The results agree well with quantum simulations available for the first 100 fs based on the same potential energy surfaces. Four different time scales are detected for the nuclear dynamics: Ultrafast Jahn--Teller dynamics between the excited states on a 5 fs time scale; fast transitions between the excited state and the ground state within a time scale of 20 fs; relatively slow partial conversion of a first-excited-state population to the ground state within a time scale of 100 fs; and nearly constant ...

  8. Microplasma stamps for selective surface modification: design and characterization

    International Nuclear Information System (INIS)

    Microplasma stamps are based upon the principle of dielectric barrier discharges. They are applied to a new type of area-selective surface modification process at atmospheric pressure. This process integrates the surface treatment and lateral microstructuring within one process step. For this purpose the plasma is ignited in cavities which are formed temporarily by compressing the microplasma stamp and the substrate to be treated. The advantage of the microplasma stamp designs described in this work is the use of polydimethylsiloxane (PDMS) as a dielectric barrier. Because of its flexibility, PDMS enables a good adjustment to varying surfaces and with it ensures completely closed cavities. In this work the design of two different microplasma stamps is presented. Both designs are characterized considering the influence of the aspect ratio on the ignition and breakdown voltage as well as the ignition under varying conditions. All experiments have been carried out at atmospheric pressure with medium frequency excitation (33 kHz). Furthermore the experimental results are verified by simulations using an SIPDP and FEM model.

  9. Microplasma stamps for selective surface modification: design and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, N; Buettgenbach, S [Institut fuer Mikrotechnik, Technische Universitaet Braunschweig, Alte Salzdahlumer Str. 203, D-38124 Braunschweig (Germany); Ermel, V; Kurrat, M [Institut fuer Hochspannungstechnik und Elektrische Energieanlagen, Technische Universitaet Braunschweig, Schleinitzstr. 23, D-38106 Braunschweig (Germany)], E-mail: n.lucas@tu-bs.de

    2008-11-07

    Microplasma stamps are based upon the principle of dielectric barrier discharges. They are applied to a new type of area-selective surface modification process at atmospheric pressure. This process integrates the surface treatment and lateral microstructuring within one process step. For this purpose the plasma is ignited in cavities which are formed temporarily by compressing the microplasma stamp and the substrate to be treated. The advantage of the microplasma stamp designs described in this work is the use of polydimethylsiloxane (PDMS) as a dielectric barrier. Because of its flexibility, PDMS enables a good adjustment to varying surfaces and with it ensures completely closed cavities. In this work the design of two different microplasma stamps is presented. Both designs are characterized considering the influence of the aspect ratio on the ignition and breakdown voltage as well as the ignition under varying conditions. All experiments have been carried out at atmospheric pressure with medium frequency excitation (33 kHz). Furthermore the experimental results are verified by simulations using an SIPDP and FEM model.

  10. Surface modification of ion implanted ultra high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jingsheng; Zhu Fuying; Pan Haochang; Cao Jianqing; Zhu Dezhang E-mail: dezhang_zhu@hotmail.com; Xu Hongjie; Cai Qing; Shen Jingen; Chen Lihua; He Zhengrui

    2000-06-02

    The surface modification has been studied for the ultra high molecular weight polyethylene (UHMWPE) implanted by 80 keV N{sub 2}{sup +}, C{sub 3}H{sub 8}{sup +} (40 keV N{sup +}, 22 keV C{sup +}) with fluences ranging from 1x10{sup 14} to 5x10{sup 15} ions/cm{sup 2}. Elastic recoil detection (ERD) and X-ray photoelectron spectroscopy (XPS) have been employed to characterize the modified surface of the samples. ERD results show that the high energy edge of ERD spectra shifts in the lower energy direction with the increase of implantation fluency, indicating that a hydrogen deficient surface layer is formed after implantation. XPS result shows that injected nitrogen atoms assist in crosslinking by forming chemical bonds with the polymer chains. KyowA's DF-PM reciprocating tester has been used to measure the wear property before and after implantation. The results show that the wear-resistance of samples after N{sub 2}{sup +}, C{sub 3}H{sub 8}{sup +} implantation has been improved by 68 and 47.5 times, respectively. Some interpretations are given to explain the observed phenomena.

  11. Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

    International Nuclear Information System (INIS)

    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 H2 and O2 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: • H2 and O2 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

  12. 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.

  13. 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

  14. Modification of Oxide Surfaces with Functional Organic Molecules, Nanoparticles, and Hetero-Oxide Layers

    OpenAIRE

    Chaudhary, Shilpi

    2015-01-01

    The research work described in this thesis is concerned with the modification of oxide surfaces, as reflected by its title. The surfaces and their modification have been studied using a range of experimental surface characterization tools, in particular x-ray photoelectron spectroscopy (XPS), fluorescence microscopy, scanning electron microscopy, atomic force microscopy, and scanning tunneling microscopy. A large part of the thesis is related to the modification of oxide or metal surfaces ...

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

    OpenAIRE

    Shazia Bashir; Muhammad Bashir; Xavier Casadevall i Solvas; Julia M. Rees; Zimmerman, William B.

    2015-01-01

    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 form...

  16. A comparative study of biomolecule and polymer surface modifications by a surface microdischarge

    Science.gov (United States)

    Bartis, Elliot A. J.; Luan, Pingshan; Knoll, Andrew J.; Graves, David B.; Seog, Joonil; Oehrlein, Gottlieb S.

    2016-02-01

    Cold atmospheric plasma (CAP) sources are attractive sources of reactive species with promising industrial and biomedical applications, but an understanding of underlying surface mechanisms is lacking. A kHz-powered surface microdischarge (SMD) operating with N2/O2 mixtures was used to study the biological deactivation of two immune-stimulating biomolecules: lipopolysaccharide (LPS) and peptidoglycan (PGN), found in bacteria such as Escherichia coli and Staphylococcus aureus, respectively. Model polymers were also studied to isolate specific functional groups. Changes in the surface chemistry were measured to understand which plasma-generated species and surface modifications are important for biological deactivation. The overall goal of this work is to determine which effects of CAP treatment are generic and which bonds are susceptible to attack. CAP treatment deactivated biomolecules, oxidized surfaces, and introduced surface bound NO3. These effects can be controlled by the N2 fraction in O2 and applied voltage and vary among different target surfaces. The SMD was compared with an Ar/O2/N2-fed kHz-powered atmospheric pressure plasma jet and showed much higher surface modifications and surface chemistry tunability compared to the jet. Possible mechanisms are discussed and findings are compared with recent computational investigations. Our results demonstrate the importance of long-lived plasma-generated species and advance an atomistic understanding of CAP-surface interactions.

  17. Non-thermal atmospheric pressure discharges for surface modification

    International Nuclear Information System (INIS)

    modification and low pressure standard methods are the thin film and surface properties. A collection of different configurations is presented, including a modular RF capillary jet along with its application for plasma enhanced CVD, plasma cleaning, plasma activation and biomedical appliances. A critical comparison of thin film and surface properties achieved with standard low pressure methods is attempted for selected applications. Concluding remarks address the evaluation of the different discharges, their chances and potential for surface treatment at atmospheric pressure. (Author)

  18. Adsorption of sodium ions and hydrated sodium ions on a hydrophobic graphite surface via cation-π interactions

    Institute of Scientific and Technical Information of China (English)

    Shi Guo-Sheng; Wang Zhi-Gang; Zhao Ji-Jun; Hu Jun; Fang Hai-Ping

    2011-01-01

    Using density functional theory computation, we show that sodium ions and hydrated sodium ions can be strongly adsorbed onto a hydrophobic graphite surface via cation-π interactions. The key to this cation-π interaction is the coupling of the delocalized π states of graphite and the empty orbitals of sodium ions. This finding implies that the property of the graphite surface is extremely dependent on the existence of the ions on the surface, suggesting that the hydrophobic property of the graphite surface may be affected by the existence of the sodium ions.

  19. Implantation-induced surface and structural modification of silica

    International Nuclear Information System (INIS)

    Full text: Ion irradiation of silica results in compaction of the substrate over the extent of the ion range where the resulting increase in refractive index has applications to optical waveguide fabrication. For the present report, several non-conventional analytical techniques have been utilised to characterise the surface and structural modifications of silica resulting from ion implantation with the aim of yielding further insight into this technologically-relevant process. Substrates of both fused silica and PECVD-grown silica-on-Si were implanted with Si ions at an energy of 5 MeV and a temperature of -196 deg C over a range of ion doses. Compaction of the substrate was characterised as a function of ion dose with both standard profilometry and extended x-ray absorption fine structure (EXAFS). With the former, saturation of the compaction at an ion dose of 1E15 /cm2 was observed. With the latter, complementary information on implantation-induced changes at the atomic scale were determined, specifically, EXAFS was used to differentiate the influences of bond length and bond angle changes in the compaction process. Furthermore, a novel in-situ photographic technique has been developed to record the state of the substrate surface, at a temperature of -196 deg C and under vacuum conditions, during ion implantation. Cracking of the surface, as a means of stress relief, was observed at doses less than that required for saturation of the compaction. Crack formation was studied as a function of both ion dose and energy, the latter to differentiate the influences of electronic and nuclear stopping processes. Thereafter, the evolution of the cracked surface was characterised as a function of temperature, pressure and ambient

  20. A study of molecular adsorption of a cationic surfactant on complex surfaces with atomic force microscopy.

    Science.gov (United States)

    Sokolov, I; Zorn, G; Nichols, J M

    2016-02-01

    The study of molecular adsorption on solid surfaces is of broad interest. However, so far the study has been restricted to idealized flat smooth rigid surfaces which are rarely the case in real world applications. Here we describe a study of molecular adsorption on a complex surface of the submicron fibers of a fibrous membrane of regenerated cellulose in aqueous media. We use a cationic surfactant, cetyltrimethylammonium chloride (CTAC), as the adsorbing molecule. We study the equilibrium adsorption of CTAC molecules on the same area of the fibers by sequentially immersing the membrane in pure water, 1 mM and then a 20 mM solution of CTAC. Atomic force microscopy (AFM) is applied to study the adsorption. The force-volume mode is used to record the force-deformation curves of the adsorbed molecules on the fiber surface. We suggest a model to separate the forces due to the adsorbed molecules from the elastic deformation of the fiber. Interestingly, knowledge of the surface geometry is not required in this model provided the surface is made of elastically homogeneous material. Different models are investigated to estimate the amount of the adsorbed molecules based on the obtained force curves. The exponential steric repulsion model fits the force data the best. The amount of the adsorbed surfactant molecules and its dependence on the concentration are found to be reasonable compared to the data previously measured by means of Raman scattering done on a flat surface of silica. PMID:26730682

  1. Synthesis of novel hybrid films of a layered silicate and alkylammonium cations on rough polymeric surfaces by Langmuir-Blodgett method.

    Science.gov (United States)

    Zhou, Qi; Wang, Kean; Loo, Leslie S

    2009-12-15

    Hybrid films of a layered silicate and an amphiphilic alkylammonium (hexadecyltrimethylammonium) cation have been prepared by Langmuir-Blodgett (LB) method and transferred onto a polyamide surface by dip coating. This is the first time that stable LB hybrid monolayer and multilayer films have been formed on rough polymeric surfaces. The films were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and water contact angle measurements. XRD and FTIR showed that the hybrid multilayer was well-organized and the thickness of one layer was calculated to be 1.6nm. Furthermore, the layered silicate was determined to be on the substrate side and the amphiphilic molecule layer was exposed to the air side. This provides a novel methodology for the surface modification of polymers. PMID:19781713

  2. Nanostructured silicon surface modifications for as a selective matrix-free laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Tsao, C W; Lin, C H; Cheng, Y C; Chien, C C; Chang, C C; Chen, W Y

    2012-06-01

    Matrix-assisted laser desorption/ionization mass spectrometry is an established soft ionization method that is widely applied to analyze biomolecules. The UV-absorbing organic matrix is essential for biomolecule ionization; however, it also creates matrix background interference, which results in problematic analyses of biomolecules of less than 700 Da. Therefore, this study investigates hydrophilic, hydrophobic cationic, anionic and immobilized metal ion surface chemical modifications to advance nanostructured silicon mass spectrometry performance (nSi-MS). This investigation provides information required for a possible novel mass spectroscopy that combines surface-enhanced and nanostructured silicon surface-assisted laser desorption/ionization mass spectrometry for the selective detection of specific compounds of a mixture. PMID:22531330

  3. Chain length dependence of non-surface activity and micellization behavior of cationic amphiphilic diblock copolymers.

    Science.gov (United States)

    Ghosh, Arjun; Yusa, Shin-ichi; Matsuoka, Hideki; Saruwatari, Yoshiyuki

    2014-04-01

    The cationic and anionic amphiphilic diblock copolymers with a critical chain length and block ratio do not adsorb at the air/water interface but form micelles in solution, which is a phenomenon called "non-surface activity". This is primarily due to the high charge density of the block copolymer, which creates a strong image charge effect at the air/water interface preventing adsorption. Very stable micelle formation in bulk solution could also play an important role in the non-surface activity. To further confirm these unique properties, we studied the adsorption and micellization behavior of cationic amphiphilic diblock copolymers of poly(n-butyl acrylate)-b-poly(3-(methacryloyloxy)ethyl)trimethylammonium chloride) (PBA-b-PDMC) with different molecular weights of hydrophobic blocks but with the same ionic block length. These block copolymers were successfully prepared via consecutive reversible addition-fragmentation chain transfer (RAFT) polymerization. The block copolymer with the shortest hydrophobic block length was surface-active; the solution showed surface tension reduction and foam formation. However, above the critical block ratio, the surface tension of the solution did not decrease with increasing polymer concentration, and there was no foam formation, indicating lack of surface activity. After addition of 0.1 M NaCl, stable foam formation and slight reduction of surface tension were observed, which is reminiscent of the electrostatic nature of the non-surface activity. Fluorescence and dynamic and static light scattering measurements showed that the copolymer with the shortest hydrophobic block did not form micelles, while the block copolymers formed spherical micelles having radii of 25-30 nm. These observations indicate that micelle formation is also important for non-surface activity. Upon addition of NaCl, cmc did not decrease but rather increased as observed for non-surface-active block copolymers previously studied. The micelles formed were

  4. Surface modifications of the Sima de los Huesos fossil humans.

    Science.gov (United States)

    Andrews, P; Fernandez Jalvo, Y

    1997-01-01

    The sample of fossil human bones from the Sima de los Huesos, Atapuerca, has been analysed to trace parts of its taphonomic history. The work reported here is restricted to analysis of the skeletal elements preserved and their surface modifications. Preliminary plans of specimen distribution published 6 years ago indicate that the skeletal elements are dispersed within the cave, but more recent data are not yet available. Most of the fossils are broken, with some breakage when the bone was fresh and some when already partly mineralized, both types showing some rounding. There are few longitudinal breaks on shafts of long bones and so very few bone splinters. All skeletal elements are preserved but in unequal proportions, with elements like femora, humeri and mandibles and teeth with greater structural density being best represented. There is no evidence of weathering or of human damage such as cut marks on any of the human assemblage, but trampling damage is present on most bones. Carnivore damage is also common, with some present on more than half the sample, but it is mostly superficial, either on the surfaces of shafts and articular ends or on the edges of spiral breaks. The sizes and distribution of the carnivore pits indicate extensive canid activity, and this is interpreted as scavenging of the bones in place in the cave. Indications of tooth marks from a larger carnivore indicate the activity possibly of a large felid: the marks are too large to be produced by small canids, with the larger marks concentrated on spiral breaks on the more robust bones, and there is no evidence of bone crushing and splintering in the manner of hyaenas. The nature of the SH human assemblage is also consistent with accumulation by humans, the evidence for this being the lack of other animals, especially the lack of herbivorous animals, associated with the humans, and the high number of individuals preserved. PMID:9300342

  5. Surface modification for titanium implants by hydroxyapatite nanocomposite

    Science.gov (United States)

    Family, Roxana; Solati-Hashjin, Mehran; Namjoy Nik, Shahram; Nemati, Ali

    2012-01-01

    Background: Titanium (Ti) implants are commonly coated with hydroxyapatite (HA). However, HA has some disadvantages such as brittleness, low tensile strength and fracture toughness. It is desirable to combine the excellent mechanical properties of ZrO2 and the chemical inertness of Al2O3 with respect to the purpose of this project which was coating Ti implants with HA-ZrO2-Al2O3 to modify the surface of these implants by adding ZrO2 and Al2O3 to HA. The purpose of this study was to evaluate the efficacy of hydroxyapatite coating nonocomposite. Methods: From September 2009 to January2011, functionally graded HA-Al2O3-ZrO2 and HA coatings were applied on Ti samples. HA-Al2O3-ZrO2 and HA sols were orderly dip coated on the substrates and calcined. Scanning electron microscopy and EDS were used to estimate the particle size of the surfaces and for morphological analysis. The morphology of non-coated HA-coated HA-Al2O3-ZrO2 (composite-coated) and double-layer composite coated samples were compared with one other. Mechanical test (heat & quench) was also done for comparing single-phase (HA), composite and double-layer composite samples. Results: The morphology of HA-Al2O3-ZrO2 coating is more homogenous than HA-coated and uncoated samples. Furthermore, single-layer coating is more homogenous than double-layer coating. EDS analysis was done on HA-coated sample and showed that the Ca/P ratio in the film was similar to the theoretical value 1.67 in HA. Conclusion: Surface modification of Ti implants can be done by coating them with single-layer of HA-Al2O3-ZrO2. Single-layer hydroxyapatite-alumina-zirconia coated sample has the most homogenous morphology on the surface. PMID:24009915

  6. The effect of surface modification on initial ice formation on aluminum surfaces

    DEFF Research Database (Denmark)

    Rahimi, Maral; Afshari, Alireza; Fojan, Peter;

    2015-01-01

    different psychrometric parameters. The obtained results show that the surface modification of aluminum plays a crucial role in the ice formation. We demonstrated that flat hydrophobic surfaces exhibit slower ice growth and denser ice layers, hence making this type of treatment preferable for aluminum heat...... material of heat exchanger fins is aluminum, this paper focuses on the effect of aluminum wettability on the initial stages of ice formation. The ice growth was studied on bare as well as hydrophilically and hydrophobically modified surfaces of aluminum (8011A) sheets, commonly used in heat exchangers, at...... exchangers. Furthermore we provide an explanation for a commonly observed phenomenon that bare aluminum surfaces are characterized by a faster ice growth and less dense ice layer as compared to both hydrophilically and hydrophobically modified surfaces....

  7. Surface modification, microstructure and mechanical properties of investment cast superalloy

    Directory of Open Access Journals (Sweden)

    M. Zielińska

    2009-07-01

    Full Text Available Purpose: The aim of this work is to determine physical and chemical properties of cobalt aluminate (CoAl2O4 modifiers produced by different companies and the influence of different types of modifiers on the grain size, the microstructure and mechanical properties of high temperature creep resisting superalloy René 77.Design/methodology/approach: The first stage of the research work took over the investigations of physical and chemical properties of cobalt aluminate manufactured by three different companies: Remet, Mason Color and Permedia Lublin. There were determined the grain size distribution of cobalt aluminate powder, the average diameter of the powder particles, phase composition, cobalt contamination. In the next step, the ceramic moulds were made with different kind of cobalt aluminate (Mason Color, Remet, Permedia Lublin and its concentration (0.5% in the primary slurry. The samples of stepped and cylindrical shape were poured in the ceramic moulds prepared earlier. The average grain size of the γ phase, was determined on the stepped samples. The microstructure investigations let to examine the influence of the surface modification on the morphology of γ ‘ - phase and carbides precipitations. Samples were turned from cylindrical castings for mechanical properties investigations: creep tests.Findings: Modification of the face coat of ceramic mould results in the reduction of the grains size of γ matrix and disintegration of carbide precipitates. It results in the improvement of mechanical properties of the alloy. On the grounds of the obtained results, it was found that the type of used modifier influenced the grain size of the alloy and its mechanical properties.Research limitations/implications: The established physical and chemical properties of modifier let to get better control of grain size of the castings and their quality what will result in decrease of defective products.Originality/value: It was proved that the

  8. NafionTM膜表面改性用等离子体聚合方法提高膜的阳离子选择性%Surface Modification of Ion Exchange Membrane(NafionTM) The Enhancement of Cation Selectivity by Plasma Polymerization Process

    Institute of Scientific and Technical Information of China (English)

    曾蓉; 朱鹤孙; 庞志成; 弋峰

    2001-01-01

    An ultra-thin anionic exchange layer containing —NH2 and —CONH2 was deposited on the surface of NafionTM membrane. This layer was deposited from ethylene and ammonia using a glow-discharge plasma polymerization technique. The SEM, ATR(attenuated total reflection) spectra and XPS(X-ray photoelectron spectroscopy) showed that the resulted plasma polymers containing —NH2 and —CONH2 was about 0.5 μm thick. The proton perm-selectivity of plasma-modified NafionTM membrane was expressed by tCu, the transference number of the Cu2+ ion through the membrane which was determined by using NafionTM membrane as the separator in a typical two-compartment cell(0.25 mol/L CuCl2-0.5mol/L HCl|plasma-modified NafionTM membrane|1 mol/L HCl). Pretreatment of the NafionTM membrane by oxygen sputtering enhanced the adhesion of plasma polymer onto its surface. The plasma-treated membrane exhibited a high perm-selectivity and its resistance in 1 mol/L HCl was only a little bit higher than NafionTM membrane(<0.5 Ω*cm2).%采用辉光放电等离子体聚合方法, 以C2H4和NH3为单体, 在NafionTM膜表面沉积一层含氨基及酰氨基的类聚乙烯阴离子交换膜, 提高了NafionTM膜对阳离子的选择性, 同时不显著增加膜电阻. 由SEM确定该等离子体聚合膜厚约0.5 μm, 用红外光谱及X光电子能谱表征膜结构. 采用四电极法测量膜电阻, 膜对质子的选择性由Cu2+的迁移数tCu表征, 用二室隔膜装置(0.25 mol/L CuCl2-0.5 mol/L HCl|等离子体处理膜|1 mol/L HCl)测量tCu. O2等离子体预处理NafionTM膜有利于沉积膜在NafionTM膜上的沉积并与NafionTM膜紧密结合. 经改性后的NafionTM膜电阻值仍然很小, 在1 mol/L HCl溶液中电阻小于0.5 Ω*cm2.

  9. Surface and antitumor activity of some novel metal-based cationic surfactants

    Directory of Open Access Journals (Sweden)

    Badawi A

    2007-01-01

    Full Text Available The development of anticancer metal-based drugs was attempted by reacting dodecyl amine with selenious acid to produce a quaternary ammonium salt which was then converted to copper and cobalt cationic complexes via complexing the first compounds with copper (II or cobalt (II ions. The surface properties of these surfactants were investigated. The surface properties studied included critical micelle concentration (CMC, maximum surface excess (Γmax , and minimum surface area (Amin . Free energy of micellization (∆G o mic and adsorption (∆Go ads were calculated. Antitumor activity was tested by using Ehrlich ascites carcinoma (EAC as a model system of mice cell tumor. The compounds were also tested in vitro on five human monolayer tumor cell lines: MCF 7 (breast carcinoma, HEPG 2 (liver carcinoma, U 251 (brain tumor, HCT116 (colon carcinoma, and H460 (lung carcinoma. FTIR spectra, elemental analysis, and H 1 NMR spectra were performed to insure the purity of the prepared compounds.

  10. Properties of rubber filled with montmorillonite with various surface modifications

    Czech Academy of Sciences Publication Activity Database

    Hrachová, J.; Komadel, P.; Janigová, I.; Šlouf, Miroslav; Chodák, I.

    2012-01-01

    Roč. 23, č. 10 (2012), s. 1414-1421. ISSN 1042-7147 Institutional research plan: CEZ:AV0Z40500505 Keywords : composite * alkylammonium cations * organo-clay Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.635, year: 2012

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

    Science.gov (United States)

    Moraczewski, Krzysztof; Stepczyńska, Magdalena; Malinowski, Rafał; Rytlewski, Piotr; Jagodziński, Bartłomiej; Żenkiewicz, Marian

    2016-07-01

    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.

  12. Modification of an Iranian clinoptilolite nano-particles by hexadecyltrimethyl ammonium cationic surfactant and dithizone for removal of Pb(II) from aqueous solution.

    Science.gov (United States)

    Anari-Anaraki, Mostafa; Nezamzadeh-Ejhieh, Alireza

    2015-02-15

    Natural clinoptilolite tuff was mechanically converted to micro (MCP) and nano (NCP) particles. The MCP and NCP powders were respectively modified with hexadecyltrimethyl ammonium bromide (HDTMA) and dithizone (DTZ). The raw and modified samples were characterized by X-ray diffraction (XRD), Fourier transformation infra red (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and thermogravimetry (TG) and used for the removal of Pb(II) from aqueous solution. The results confirm that both ion exchange and complexation processes are responsible for removal of Pb(II) cations in the modified samples, while Pb(II) cations were only removed via an ion exchange process by the raw clinoptilolite. In this sorbent, the anionic removal property of surfactant modified zeolites (SMZs) changed to cationic removal property by an additional modification step. The best removal efficiency was observed by NCP-HDTMA-DTZ at the following experimental conditions: C(Pb(II)): 800 mg L(-1), HDTMA dosage: 0.2 mol L(-1), DTZ dosage: 5 mmol L(-1), contact time of DTZ with NCP-HDTMA: 1800 min and contact time of the sorbent with Pb(II): 360 min. The NCP-HDTMA-DTZ sorbent showed good efficiency for the removal of lead in the presence of different multivalent cations. Adsorption isotherms of Pb(II) ions obey the Langmuir equation that indicate the monolayer sorption of Pb(II). The adsorption kinetics based on the pseudo-second-order rate equation indicates that the rate limiting step involving a chemical reaction. The negative ΔH and ΔG indicate an exothermic and spontaneous process. PMID:25460715

  13. Studies on polyurethane adhesives and surface modification of hydrophobic substrates

    Science.gov (United States)

    Krishnamoorthy, Jayaraman

    studies involved making functionalized, thickness-controlled, wettability-controlled multilayers on hydrophobic substrates and the adsorption of carboxylic acid-terminated poly(styrene-b-isoprene) on alumina/silica substrates. Poly(vinyl alcohol) has been shown to adsorb onto hydrophobic surfaces irreversibly due to hydrophobic interactions. This thin semicrystalline coating is chemically modified using acid chlorides, butyl isocyanate and butanal to form thicker and hydrophobic coatings. The products of the modification reactions allow adsorption of a subsequent layer of poly(vinyl alcohol) that could subsequently be hydrophobized. This 2-step (adsorption/chemical modification) allows layer-by-layer deposition to prepare coatings with thickness, chemical structure and wettability control on any hydrophobic surface. Research on adsorption characteristics of carboxylic acid-terminated poly(styrene-b-isoprene) involved syntheses of block copolymers with the functional group present at specific ends. Comparative adsorption studies for carboxylic acid-terminated and hydrogen-terminated block copolymers was carried out on alumina and silica substrates.

  14. Metal ion implantation for large scale surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Brown, I.G.

    1992-10-01

    Intense energetic beams of metal ions can be produced by using a metal vapor vacuum arc as the plasma discharge from which the ion beam is formed. We have developed a number of ion sources of this kind and have built a metal ion implantation facility which can produce repetitively pulsed ion beams with mean ion energy up to several hundred key, pulsed beam current of more than an ampere, and time averaged current of several tens of milliamperes delivered onto a downstream target. We've also done some preliminary work on scaling up this technology to very large size. For example, a 50-cm diameter (2000 cm[sup 2]) set of beam formation electrodes was used to produce a pulsed titanium beam with ion current over 7 amperes at a mean ion energy of 100 key. Separately, a dc embodiment has been used to produce a dc titanium ion beam with current over 600 mA, power supply limited in this work, and up to 6 amperes of dc plasma ion current was maintained for over an hour. In a related program we've developed a plasma immersion method for applying thin metallic and compound films in which the added species is atomically mixed to the substrate. By adding a gas flow to the process, well-bonded compound films can also be formed; metallic films and multilayers as well as oxides and nitrides with mixed transition zones some hundreds of angstroms thick have been synthesized. Here we outline these parallel metal-plasma-based research programs and describe the hardware that we've developed and some of the surface modification research that we've done with it.

  15. Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption.

    Science.gov (United States)

    Sipponen, Mika Henrikki; Pihlajaniemi, Ville; Littunen, Kuisma; Pastinen, Ossi; Laakso, Simo

    2014-10-01

    A new colorimetric method for determining the surface-accessible acidic lignin hydroxyl groups in lignocellulose solid fractions was developed. The method is based on selective adsorption of Azure B, a basic dye, onto acidic hydroxyl groups of lignin. Selectivity of adsorption of Azure B on lignin was demonstrated using lignin and cellulose materials as adsorbents. Adsorption isotherms of Azure B on wheat straw (WS), sugarcane bagasse (SGB), oat husk, and isolated lignin materials were determined. The maximum adsorption capacities predicted by the Langmuir isotherms were used to calculate the amounts of surface-accessible acidic hydroxyl groups. WS contained 1.7-times more acidic hydroxyls (0.21 mmol/g) and higher surface area of lignin (84 m(2)/g) than SGB or oat husk materials. Equations for determining the amount of surface-accessible acidic hydroxyls in solid fractions of the three plant materials by a single point measurement were developed. A method for high-throughput characterization of lignocellulosic materials is now available. PMID:25033327

  16. Statistical Modification Analysis of Helical Planetary Gears based on Response Surface Method and Monte Carlo Simulation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; GUO Fan

    2015-01-01

    Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system’s dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error(DTE) fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system’s dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.

  17. Combined effect of electric field and surface modification on pool boiling of R-123

    OpenAIRE

    Ahmad, Syed Waqas

    2012-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The effect of surface modification and high intensity electric field (uniform and non – uniform) acting separately or in combination on pool boiling of R-123 is presented in this thesis. The effect of surface modification was investigated on saturated pool boiling of R-123 for five horizontal copper surfaces modified by different treatments, namely: an emery polished surface, a fine sandblast...

  18. Fabrication of Superhydrophobic Aluminum Plate by Surface Etching and Fluorosilane Modification

    Institute of Scientific and Technical Information of China (English)

    YIN Shi-heng; ZHU Bin; LIU Yun-chun; YANG Ji; KUANG Tong-chun

    2012-01-01

    Superhydrophobic aluminum surfaces with a high water contact angle and low sliding angle on aluminum plate substrate were fabricated by means of surface etching with sodium hydroxide under ultrasonic bathing and then modification with fluorosilane.Scanning electron microscopy(SEM) showed a honeycomb-like structure on aluminum substrate surface after etching under ultrasonic bathing.And the surface was rendered from superhydrophilicity to superhydrophobicity after further modification with fluorosilane.

  19. Determination of surface-accessible acidic hydroxyls and surface area of lignin by cationic dye adsorption

    OpenAIRE

    Sipponen, Mika Henrikki; Pihlajaniemi, Ville; Littunen, Kuisma; Pastinen, Ossi; Laakso, Simo

    2014-01-01

    A new colorimetric method for determining the surface-accessible acidic lignin hydroxyl groups in lignocellulose solid fractions was developed. The method is based on selective adsorption of Azure B, a basic dye, onto acidic hydroxyl groups of lignin. Selectivity of adsorption of Azure B on lignin was demonstrated using lignin and cellulose materials as adsorbents. Adsorption isotherms of Azure B on wheat straw (WS), sugarcane bagasse (SGB), oat husk, and isolated lignin materials were determ...

  20. Hydrophilic modification of polyester fabric by applying nanocrystalline cellulose containing surface finish.

    Science.gov (United States)

    Zaman, Masuduz; Liu, Hongbin; Xiao, Huning; Chibante, Felipe; Ni, Yonghao

    2013-01-16

    In this study, polyethylene terephthalate (PET) fabric was modified by applying a hydrophilic surface finishing agent that contains nanocrystalline cellulose (NCC). To impart superior hydrophilicity, NCC was further cationically modified through quaternization by grafting glycidyl tri-methyl ammonium chloride (GTMAC). A textile binder, PrintRite595(®), was added to the finishing system. The surface finish was applied on the fabric using a rolling-drying-curing process. The modified fabric was characterized in terms of coating durability, moisture regain, and wettability. The durability of the surface finish was tested by six repeated washing steps. The surface properties of the fabric changed from hydrophobic to hydrophilic after heat treatment with the NCC-containing surface finishing agent. The results from the washing fastness, SEM, FTIR, and EDX analyses confirmed that the cationic NCC-containing textile surface finish showed superior adhesion onto the cationic dyeable (anionic) PET surface over the un-modified NCC. Furthermore, the cationic textile surface finish was capable of withstanding multiple washing cycles. PMID:23121945

  1. CATION-EXCHANGE MEMBRANES WITH POLYANILINE SURFACE LAYER FOR WATER TREATMENT

    Directory of Open Access Journals (Sweden)

    Dinar Dilshatovich Fazullin

    2014-01-01

    Full Text Available Ion-exchange membranes are widely used in modern technologies, particularly in the field of water treatment and make it possible to considerably reduce expenses for wastewater treatment and ensure high degree of purification. Currently, perfluorinated sulfated proton-conducting membranes are often used, such as NAFION and its Russian analogue, MF-4SK based on co-polymerization product of a perfluorinated vinyl ether with tetrafluoroethylene. However, with development of the industry, materials with improved properties and lower cost are required. The aim is to obtain ion-exchange membranes for water treatment from metal ions and to study physico-chemical properties of obtained membranes. In this study, cation exchange composite membranes with modified polyaniline surface layer on nylon and PTFE substrate have been obtained. Changes in the structure of membranes were recorded using a microscope. Throughput capacity of the membranes was determined by passing a certain volume of distilled water through the membrane. The experiment intended to determine electivity of membranes was performed by passing a certain volume of metal salt solutions of a known concentration, after which the filtrate was collected. Concentrations of the studied metal ions in the original solution and in the filtrate were determined by the method of atomic adsorptive spectrometry with electro thermal atomization "Quantum Z.ETA". Prepared highly selective ion exchange membranes. Properties of modified membranes, such as selective permeability and ion-exchange capacity have been determined. The membranes feature high selectivity for heavy metal ions. Moisture-retaining power and swelling ability of the membranes have been studied. Selectivity of the membrane to heavy metal ions is between 70 and 99%. Ion-exchange capacity of the obtained nylon polyaniline membrane is not inferior to some commercially available cation-exchange membranes. Use of the modified membranes in the

  2. Effect of Water Adsorption on Cation-Surface Interaction Energy in the Na-Mordenite of 5.5 : 1 Si/Al Ratio

    OpenAIRE

    Sekou Diaby

    2016-01-01

    The mobility of the Na+ cations localized at the inner surface of the studied mordenite zeolite depends on the material surface properties. In this work, we show that the activation energy, ΔEhop, relating to the Na+ cation hopping displacement is associated to the surface potential and therefore can be used to get a better insight into the zeolite surface properties. Indeed, when molecules as water are adsorbed at the surface, they modify the surface potential energy and hence influence the ...

  3. Cationic and anionic polyelectrolyte complexes of xylan and chitosan. Interaction with lignocellulosic surfaces.

    Science.gov (United States)

    Mocchiutti, Paulina; Schnell, Carla N; Rossi, Gerardo D; Peresin, María S; Zanuttini, Miguel A; Galván, María V

    2016-10-01

    Cationic (CatPECs) and anionic (AnPECs) polyelectrolyte complexes from xylan and chitosan were formed, characterized and adsorbed onto unbleached fibers for improving the papermaking properties. They were prepared at a level of 30% of neutralization charge ratio by modifying the order of addition of polyelectrolytes and the ionic strength (0.01N and 0.1N NaCl). The charge density, colloidal stability and particle size of polyelectrolyte complexes (PECs) was measured using polyelectrolyte titration method, Turbiscan and Zetasizer Nano equipments, respectively. All the complexes were stable even after seven days from PEC formation. DRIFT spectra of complexes were also analyzed. The adsorption behavior of them onto cellulose nanofibrils model surfaces was studied using quartz crystal microbalance with dissipation monitoring, and surface plasmon resonance. It was found that the PEC layers were viscoelastic and highly hydrated. Finally, it is shown that the adsorbed PECs onto cellulosic fibers markedly improved the tensile and crushing strengths of paper. PMID:27312617

  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. PET表面改性研究进展%Research progress in PET surface modification

    Institute of Scientific and Technical Information of China (English)

    王甜甜; 王晓春; 赵国樑

    2011-01-01

    The research progress in polyethylene terephthalate ( PET) surface modification was reviewed in China and abroad. The PET surface modification technologies included chemical grafting modification, ultraviolet irradiation grafting modification, high energy irradiation grafting modification, plasma grafting modification and ozone oxidizing modification. The surface modification could improve the hydrophilicity, antistatic behavior, adhesion and biocompatibility of PET. The application of modified PET was introduced in the related fields. It was pointed out that the key scientific and technical problems in PET surface modification should be solved.%综述了国内外聚对苯二甲酸乙二醇酯(PET)的表面改性研究进展.PET表面改性方法主要有:化学接枝改性、紫外光辐照接枝改性、高能射线辐照接枝改性、等离子体处理接枝改性以及臭氧氧化改性等;通过PET表面改性,可以改善PET的亲水性、抗静电性、粘附性和生物相容性等性能;介绍了改性PET在相关领域中的应用;指出PET的表面改性技术尚有许多关键科学问题和技术难题需解决.

  6. Improved electrochemical stability at the surface of La(0.8)Sr(0.2)CoO3 achieved by surface chemical modification.

    Science.gov (United States)

    Tsvetkov, Nikolai; Lu, Qiyang; Yildiz, Bilge

    2015-01-01

    The degradation of the surface chemistry on perovskite (ABO3) oxides is a critical issue for their performance in energy conversion systems such as solid oxide fuel/electrolysis cells and in splitting of H2O and CO2 to produce fuels. This degradation is typically in the form of segregation and phase separation of dopant cations from the A-site, driven by elastic and electrostatic energy minimization and kinetic demixing. In this study, deposition of Ti at the surface was found to hinder the dopant segregation and the corresponding electrochemical degradation on a promising SOFC cathode material, La(0.8)Sr(0.2)CoO3 (LSC). The surface of the LSC films was modified by Ti (denoted as LSC-T) deposited from a TiCl4 solution. The LSC and LSC-T thin films were investigated by electrochemical impedance spectroscopy, nano-probe Auger electron spectroscopy, and X-ray photoelectron spectroscopy (XPS), upon annealing at 420-530 °C in air up to about 90 hours. The oxygen exchange coefficient, k(q), on LSC-T cathodes was found to be up to 8 times higher than that on LSC cathodes at 530 °C and retained its stability. Sr-rich insulating particles formed at the surface of the annealed LSC and LSC-T films, but with significantly less coverage of such particles on the LSC-T. From this result, it appears that modification of the LSC surface with Ti reduces the segregation of the blocking Sr-rich particles at the surface, and a larger area on LSC surface (with a higher Sr doping level in the lattice) is available for the oxygen reduction reaction. The stabilization of the LSC surface through Ti-deposition can open a new route for designing surface modifications on perovskite oxide electrodes for high temperature electro- and thermo-chemical applications. PMID:26227310

  7. Bio-inspired dual surface modification to improve tribological properties at small-scale

    Science.gov (United States)

    Singh, R. Arvind; Pham, Duc-Cuong; Kim, Jinseok; Yang, Sungwook; Yoon, Eui-Sung

    2009-02-01

    In miniaturized devices like micro/nano-electro-mechanical systems (MEMS/NEMS), the critical forces, namely adhesion and friction restrict the smooth operation of the elements that are in relative motion. MEMS/NEMS are traditionally made of silicon, whose tribological properties are not good. In this paper, we present an investigation on the approach of dual surface modification of silicon surfaces and their tribological properties at micro-scale. The dual surface modification is a combination of topographical and chemical modifications. As the topographical modification, micro-patterns with varying shapes of pillars and channels were fabricated on Si(1 0 0) wafer surfaces using photolithography method. Chemical modification included the coating of micro-patterns with diamond-like carbon (DLC) and Z-DOL (perfluoropolyether, PFPE) thin films. The surfaces with combined modification were evaluated for their micro-friction behavior in comparison with those of bare Si(1 0 0) flat surfaces and the topographically/chemically modified silicon surfaces. Results showed that the surfaces with dual modification exhibited superior tribological properties. These results indicate that a combination of topographical and chemical modification is very effective in enhancing tribological properties at small-scale. The combined surface treatments such as the ones investigated in the current work could be useful for tribological applications in small-scale devices such as MEMS/NEMS. The motivation for undertaking the dual modification approach comes from an earlier observation made on the significant influence of the surface characteristics of lotus leaf on its micro-friction behavior.

  8. Synthesis and surface modification of magnetic particles for application in biotechnology and biomedicine

    Institute of Scientific and Technical Information of China (English)

    Zhiya Ma; Huizhou Liu

    2007-01-01

    Magnetic particles have numerous applications in biotechnology and biomedicine. In this paper we reviewed the synthesis, surface modification and some applications of magnetic particles with focus on their synthesis and surface modification. Various methods have been developed for the production of magnetic particles (magnetic nanoparticles and magnetic composite particles). For future application magnetic particles must be modified to obtain stability and surface functional groups. Finally, the application of magnetic particles in magnetic separation, drug delivery,hyperthermia, and magnetic resonance imaging are discussed.

  9. Preparation and studies on surface modifications of calcium-silico-phosphate ferrimagnetic glass-ceramics in simulated body fluid

    International Nuclear Information System (INIS)

    The structure and magnetic behaviour of 34SiO2-(45 - x) CaO-16P2O5-4.5 MgO-0.5 CaF2 - x Fe2O3 (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 [Fe2+/Fe3+] ions ratio depends on the composition of glass and varied with Fe2O3 concentration in glass matrix. In glass-ceramics saturation magnetization increases with increase in amount of Fe2O3. The nanostructure of hematite and magnetite is formed in the glass-ceramics with 15 and 20 wt.% Fe2O3, which is responsible for the magnetic property of these glass-ceramics. Introduction of Fe2O3 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. Mechano-activated surface modification of calcium carbonate in wet stirred mill and its properties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification of calcium carbonate particles using sodium stearate(SDS) as a modification agent incorporated with the simultaneous wet ultra-fine grinding in the laboratory stirred mill was investigated. The physical properties and application properties of modified calcium carbonate were measured and evaluated. The action mechanism between SDS and calcium carbonate in the modification was studied by infrared spectrometry(IR) and X-ray photoelectron energy spectroscopy(XPS). The results indicate that the crushing mechanic force intensity can obviously influence the modification effect of calcium carbonate because of mechano-chemical effect. The hydrophilic surface of calcium carbonate is turned into hydrophobic after modification. The properties of polyethylene(PE) filled by modified calcium carbonate powder is markedly improved. And the adsorption of SDS could occur by chemical reaction with calcium carbonate surface.

  11. Surface Charge Density Determines the Efficiency of Cationic Gemini Surfactant Based Lipofection

    Science.gov (United States)

    Ryhänen, Samppa J.; Säily, Matti J.; Paukku, Tommi; Borocci, Stefano; Mancini, Giovanna; Holopainen, Juha M.; Kinnunen, Paavo K. J.

    2003-01-01

    The efficiencies of the binary liposomes composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and cationic gemini surfactant, (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide as transfection vectors, were measured using the enhanced green fluorescent protein coding plasmid and COS-1 cells. Strong correlation between the transfection efficiency and lipid stoichiometry was observed. Accordingly, liposomes with XSR−1 ≥ 0.50 conveyed the enhanced green fluorescent protein coding plasmid effectively into cells. The condensation of DNA by liposomes with XSR−1 > 0.50 was indicated by static light scattering and ethidium bromide intercalation assay, whereas differential scanning calorimetry and fluorescence anisotropy of diphenylhexatriene revealed stoichiometry dependent reorganization in the headgroup region of the liposome bilayer, in alignment with our previous Langmuir-balance study. Surface charge density and the organization of positive charges appear to determine the mode of interaction of DNA with (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide/1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes, only resulting in DNA condensation when XSR−1 > 0.50. Condensation of DNA in turn seems to be required for efficient transfection. PMID:12524311

  12. Surface Modification of Exfoliated Graphite Nano-Reinforcements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I results showed that two surface treatments, oxidative plasma and reactive finishes, are effective means of modifying the surface chemistry of exfoliated...

  13. Holographic microscopy provides new insights into the settlement of zoospores of the green alga Ulva linza on cationic oligopeptide surfaces.

    Science.gov (United States)

    Vater, Svenja M; Finlay, John; Callow, Maureen E; Callow, James A; Ederth, Thomas; Liedberg, Bo; Grunze, Michael; Rosenhahn, Axel

    2015-01-01

    Interaction of zoospores of Ulva linza with cationic, arginine-rich oligopeptide self-assembled monolayers (SAMs) is characterized by rapid settlement. Some spores settle (ie permanently attach) in a 'normal' manner involving the secretion of a permanent adhesive, retraction of the flagella and cell wall formation, whilst others undergo 'pseudosettlement' whereby motile spores are trapped (attached) on the SAM surface without undergoing the normal metamorphosis into a settled spore. Holographic microscopy was used to record videos of swimming zoospores in the vicinity of surfaces with different cationic oligopeptide concentrations to provide time-resolved insights into processes associated with attachment of spores. The data reveal that spore attachment rate increases with increasing cationic peptide content. Accordingly, the decrease in swimming activity in the volume of seawater above the surface accelerated with increasing surface charge. Three-dimensional trajectories of individual swimming spores showed a 'hit and stick' motion pattern, exclusively observed for the arginine-rich peptide SAMs, whereby spores were immediately trapped upon contact with the surface. PMID:25875964

  14. Simultaneous Sterilization With Surface Modification Of Plastic Bottle By Plasma-Based Ion Implantation

    Science.gov (United States)

    Sakudo, N.; Ikenaga, N.; Ikeda, F.; Nakayama, Y.; Kishi, Y.; Yajima, Z.

    2011-01-01

    Dry sterilization of polymeric material is developed. The technique utilizes the plasma-based ion implantation which is same as for surface modification of polymers. Experimental data for sterilization are obtained by using spores of Bacillus subtilis as samples. On the other hand we previously showed that the surface modification enhanced the gas barrier characteristics of plastic bottles. Comparing the implantation conditions for the sterilization experiment with those for the surface modification, we find that both sterilization and surface modification are simultaneously performed in a certain range of implantation conditions. This implies that the present bottling system for plastic vessels will be simplified and streamlined by excluding the toxic peroxide water that has been used in the traditional sterilization processes.

  15. Surface modification of active material structures in battery electrodes

    Science.gov (United States)

    Erickson, Michael; Tikhonov, Konstantin

    2016-02-02

    Provided herein are methods of processing electrode active material structures for use in electrochemical cells or, more specifically, methods of forming surface layers on these structures. The structures are combined with a liquid to form a mixture. The mixture includes a surface reagent that chemically reacts and forms a surface layer covalently bound to the structures. The surface reagent may be a part of the initial liquid or added to the mixture after the liquid is combined with the structures. In some embodiments, the mixture may be processed to form a powder containing the structures with the surface layer thereon. Alternatively, the mixture may be deposited onto a current collecting substrate and dried to form an electrode layer. Furthermore, the liquid may be an electrolyte containing the surface reagent and a salt. The liquid soaks the previously arranged electrodes in order to contact the structures with the surface reagent.

  16. Surface modification of polymer nanofibres by plasma treatment

    International Nuclear Information System (INIS)

    Polymer nanofibres have great potential for technical applications in biomaterials, filtration, composites and electronics. The surface properties of nanofibres are of importance in these applications. In this study, cold gas plasma treatment was used to modify the surface of polyamide 6 nanofibres prepared by electrospinning. The chemical nature of the nanofibre surfaces was examined by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was employed to study the surface characteristics of the fibres. The AFM results indicate a significant change in the morphology of the fibre surface before and after plasma treatment. A Philips Environmental Scanning Electron Microscopy (ESEM) was also used to study the wetting behaviour of the fibres. In the ESEM, relative humidity was raised to 100% to facilitate the water condensation onto fibre surfaces for wetting observation. The ESEM observation revealed that the plasma treatment significantly altered the surface wettability of the polyamide 6 nanofibres

  17. Surface modification of polymer nanofibres by plasma treatment

    Science.gov (United States)

    Wei, Q. F.; Gao, W. D.; Hou, D. Y.; Wang, X. Q.

    2005-05-01

    Polymer nanofibres have great potential for technical applications in biomaterials, filtration, composites and electronics. The surface properties of nanofibres are of importance in these applications. In this study, cold gas plasma treatment was used to modify the surface of polyamide 6 nanofibres prepared by electrospinning. The chemical nature of the nanofibre surfaces was examined by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was employed to study the surface characteristics of the fibres. The AFM results indicate a significant change in the morphology of the fibre surface before and after plasma treatment. A Philips Environmental Scanning Electron Microscopy (ESEM) was also used to study the wetting behaviour of the fibres. In the ESEM, relative humidity was raised to 100% to facilitate the water condensation onto fibre surfaces for wetting observation. The ESEM observation revealed that the plasma treatment significantly altered the surface wettability of the polyamide 6 nanofibres

  18. Surface modification of polymer nanofibres by plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Q.F. [Southern Yangtze University, Wuxi 214063 (China) and Anhui University of Technology and Science, Wuhu 241000 (China)]. E-mail: qufu_wei@sina.com; Gao, W.D. [Southern Yangtze University, Wuxi 214063 (China); Anhui University of Technology and Science, Wuhu 241000 (China); Hou, D.Y. [Anhui University of Technology and Science, Wuhu 241000 (China); Wang, X.Q. [Anhui University of Technology and Science, Wuhu 241000 (China)

    2005-05-30

    Polymer nanofibres have great potential for technical applications in biomaterials, filtration, composites and electronics. The surface properties of nanofibres are of importance in these applications. In this study, cold gas plasma treatment was used to modify the surface of polyamide 6 nanofibres prepared by electrospinning. The chemical nature of the nanofibre surfaces was examined by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was employed to study the surface characteristics of the fibres. The AFM results indicate a significant change in the morphology of the fibre surface before and after plasma treatment. A Philips Environmental Scanning Electron Microscopy (ESEM) was also used to study the wetting behaviour of the fibres. In the ESEM, relative humidity was raised to 100% to facilitate the water condensation onto fibre surfaces for wetting observation. The ESEM observation revealed that the plasma treatment significantly altered the surface wettability of the polyamide 6 nanofibres.

  19. Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

    International Nuclear Information System (INIS)

    The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ≤ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

  20. Lessons learned from the Febex in situ test: modifications at cation exchange positions by effect of a thermo-hydraulic gradient and the bentonite pore water

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Compacted bentonites are considered as a backfill and sealing material in most high-level radioactive waste disposal (HLW) concepts because of its physico-chemical properties. One of these properties arises from the electrical charge on the clay mineral surfaces, which affects the bentonite capacity for interacting with water and solutes. The total electrical charge distribution in clay particles is centred in two surface functional groups that give rise to different reactivities: a) aluminol and silanol edge surface hydroxyl groups, where the surface complexation processes occur; and 2) siloxane di-trigonal cavities or siloxane surfaces, where the exchange reactions take place. The excess of negative charge (CEC parameter) has important repercussions in degree of swelling, hydration, rheological properties, acid/base properties and adsorption/retention of cations in clays. In the last years, the accurate determination of the CEC and the concentration of cations at exchange positions have been one of the main problems tackled, and a lot of procedures and methods are found in the literature. This is because the CEC depends on the measurement conditions: pH, ionic strength, solid to liquid ratio, temperature and dielectric constant of the medium. The standard method by using NH4OAC 1 M at pH 7 and 25 C has a lot of drawbacks. For this reason, there are other methods based on: a) extracting solutions at pH 8.2 for limiting the dissolution of carbonates; b) organic solvents less polar than water limiting dissolution of sulfates also; and c) solutions with cations of high affinity (Cs, Co(NO3)63+ or Ag-Thiourea saturated in calcite). In the FEBEX project, different methods were used for analysing the CEC and cation concentration at exchange sites in different laboratory tests. These include tests with bentonite at as received or natural conditions and bentonite subjected to heating and hydration in thermo

  1. Surface modification of polymeric materials by plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Polymer surfaces typically have low surface tension and high chemical inertness and so they usually have poor wetting and adhesion properties. The surface properties can be altered by modifying the molecular structure using plasma immersion ion implantation (PIII). In this work, Nylon-6 was treated using oxygen/nitrogen PIII. The observed improvement in the wettability is due to the oxygenated and nitrogen (amine) functional groups created on the polymer surface by the plasma treatment. X-ray photoelectron spectroscopy (XPS) results show that nitrogen and oxygen plasma implantation result in C-C bond breaking to form the imine and amine groups as well as alcohol and/or carbonyl groups on the surface. The water contact angle results reveal that the surface wetting properties depend on the functional groups, which can be adjusted by the ratio of oxygen-nitrogen mixtures

  2. Superhydrophobic alumina surface based on stearic acid modification

    International Nuclear Information System (INIS)

    A novel superhydrophobic alumina surface is fabricated by grafting stearic acid layer onto the porous and roughened aluminum film. The chemical and phase structure, morphology, and the chemical state of the atoms at the superhydrophobic surface were investigated by techniques as FTIR, XRD, FE-SEM, and XPS, respectively. Results show that a super water-repellent surface with a contact angle of 154.2o is generated. The superhydrophobic alumina surface takes on an uneven flowerlike structure with many nanometer-scale hollows distribute in the nipple-shaped protrusions, and which is composed of boehmite crystal and γ-Al2O3. Furthermore, the roughened and porous alumina surface is coated with a layer of hydrophobic alkyl chains which come from stearic acid molecules. Therefore, both the roughened structure and the hydrophobic layer endue the alumina surface with the superhydrophobic behavior.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Yu [AML and CNMM, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Xu, Yuanjie [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Wang, Gang-Feng [Department of Engineering Mechanics, Xi' an Jiaotong University, Xi' an 710049 (China); Gu, Yuantong [School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane 4001 (Australia); Feng, Xi-Qiao, E-mail: fengxq@tsinghua.edu.cn [AML and CNMM, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

    2015-09-18

    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.

  5. Surface Modifications and Their Effects on Titanium Dental Implants

    OpenAIRE

    Jemat, A.; Ghazali, M. J.; M. Razali; Otsuka, Y.

    2015-01-01

    This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effecti...

  6. Surface Modification of Titanium Dental Implants by Excimer Laser

    OpenAIRE

    Radnai, M.; Bereznai, M.; Pelseczi, I.; Toth, Z.; Turzo, K.; Bor, Z.; Fazekas, A.

    2002-01-01

    The perfect osseointegration process of the dental implants depends among other factors on the surfact characteristics of the titanium. In this study enlarged mechanical roughness was produced by a laser-based technique, in order to decrease the healing period of the implant. There are different ways of forming laser induced surface structures. In the case of mask projection techniques the surface can be modified in larger areas and surface patterns. An ArF nanosecond excimer laser was use...

  7. Reality of Dental Implant Surface Modification: A Short Literature Review

    OpenAIRE

    Yeo, In-Sung

    2014-01-01

    Screw-shaped endosseous implants that have a turned surface of commercially pure titanium have a disadvantage of requiring a long time for osseointegration while those implants have shown long-term clinical success in single and multiple restorations. Titanium implant surfaces have been modified in various ways to improve biocompatibility and accelerate osseointegration, which results in a shorter edentulous period for a patient. This article reviewed some important modified titanium surfaces...

  8. Ammonia modification of oxide-free Si(111) surfaces

    Science.gov (United States)

    Chopra, Tatiana Peixoto; Longo, Roberto C.; Cho, Kyeongjae; Chabal, Yves J.

    2016-08-01

    Amination of surfaces is useful in a variety of fields, ranging from device manufacturing to biological applications. Previous studies of ammonia reaction on silicon surfaces have concentrated on vapor phase rather than wet chemical processes, and mostly on clean Si surfaces. In this work, the interaction of liquid and vapor-phase ammonia is examined on three types of oxide-free surfaces - passivated by hydrogen, fluorine (1/3 monolayer) or chlorine - combining infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and first-principles calculations. The resulting chemical composition highly depends on the starting surface; there is a stronger reaction on both F- and Cl-terminated than on the H-terminated Si surfaces, as evidenced by the formation of Si-NH2. Side reactions can also occur, such as solvent reaction with surfaces, formation of ammonium salt by-products (in the case of 0.2 M ammonia in dioxane solution), and nitridation of silicon (in the case of neat and gas-phase ammonia reactions for instance). Unexpectedly, there is formation of Si-H bonds on hydrogen-free Cl-terminated Si(111) surfaces in all cases, whether vapor phase of neat liquid ammonia is used. The first-principles modeling of this complex system suggests that step-edge surface defects may play a key role in enabling the reaction under certain circumstances, despite the endothermic nature for Si-H bond formation.

  9. Surface modification of synthetic rubbers by UV, ion-etching, and low energy EB irradiation

    International Nuclear Information System (INIS)

    Surface modification processing of two kinds of synthetic rubbers (ethylene-propylene, and chloroprene) by ultraviolet (UV), sputter ion etching, and electron beam (EB) irradiation treatments has been studied in relation to the modification mechanisms. The most remarkable effect of these treatments was (1) the rapid increase of adhesion properties and (2) simultaneously decrease of self-stickiness. This non-sticking effect was particularly important for the rapid production of thin rubber sheet articles. The effectiveness was in the following order: ion etching>UV>EB. The surface modification mechanism was studied by use of SEM, ESCA, FT-IR, and related interfacial analytical procedures

  10. Dropwise Evaporative Cooling of Heated Surfaces with Various Wettability Characteristics Obtained by Nanostructure Modifications

    OpenAIRE

    Chen, Jian-Nan; Zhang, Zhen; Ouyang, Xiao-long; Jiang, Pei-xue

    2016-01-01

    A numerical and experimental investigation was conducted to analyze dropwise evaporative cooling of heated surfaces with various wettability characteristics. The surface wettability was tuned by nanostructure modifications. Spray-cooling experiments on these surfaces show that surfaces with better wettability have better heat transfer rate and higher critical heat flux (CHF). Single droplet impingement evaporative cooling of a heated surface was then investigated numerically with various wett...

  11. Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives - their stability, complexation ability in solution or when deposited on solid anionic surface.

    Science.gov (United States)

    Popr, Martin; Filippov, Sergey K; Matushkin, Nikolai; Dian, Juraj; Jindřich, Jindřich

    2015-01-01

    The thermal stability of the monosubstituted cationic cyclodextrin (CD) derivatives PEMEDA-β-CD and PEMPDA-β-CD, which differ in their substituent linker length (ethylene and propylene, respectively), was studied via (1)H NMR experiments. PEMPDA-β-CD exhibited higher resistance towards the Hofmann degradation and was chosen as a more suitable host molecule for further studies. Inclusion properties of PEMPDA-β-CD in solution with a series of simple aromatic guests (salicylic acid, p-methoxyphenol and p-nitroaniline) were determined by isothermal titration calorimetry (ITC) and compared to the native β-CD. Permanently charged cationic CD derivatives were successfully deposited on the anionic solid surface of polymeric Nafion(®) 117 membrane via electrostatic interactions. Deposition kinetics and coverage of the surface were determined by ELSD. Finally, the ability of the CD derivatives bound to the solid surface to encapsulate aromatic compounds from aqueous solution was measured by UV-vis spectroscopy. The obtained results are promising for future industrial applications of the monosubstituted β-CD derivatives, because the preparation of cationic CD derivatives is applicable in large scale, without the need of chromatographic purification. Their ionic deposition on a solid surface is simple, yet robust and a straightforward process as well. PMID:25815069

  12. A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

    Directory of Open Access Journals (Sweden)

    Tina Govindarajan

    2014-08-01

    Full Text Available The search for a single material with ideal surface properties and necessary mechanical properties is on-going, especially with regard to cardiovascular stent materials. Since the majority of stent problems arise from surface issues rather than bulk material deficiencies, surface optimization of a material that already contains the necessary bulk properties is an active area of research. Polymers can be surface-modified using a variety of methods to increase hemocompatibilty by reducing either late-stage restenosis or acute thrombogenicity, or both. These modification methods can be extended to shape memory polymers (SMPs, in an effort to make these materials more surface compatible, based on the application. This review focuses on the role of surface modification of materials, mainly polymers, to improve the hemocompatibility of stent materials; additional discussion of other materials commonly used in stents is also provided. Although shape memory polymers are not yet extensively used for stents, they offer numerous benefits that may make them good candidates for next-generation stents. Surface modification techniques discussed here include roughening, patterning, chemical modification, and surface modification for biomolecule and drug delivery.

  13. Modification of the glass surface induced by redox reactions and internal diffusion processes

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Deubener, Joachim; Yue, Yuanzheng

    In this paper we report a novel way to modify the glass surface in favor of some physical performances. The main step is to perform iso-thermal treatments on the selected silicate glasses containing transition metal at temperatures near the glass transition temperature for various durations under...... different gases. As a result, we have observed a striking phenomenon, i.e., the outward diffusion of divalent cations occurs not only under an oxidizing atmosphere of heat-treatment, but also under nitrogen, even under reducing atmospheres like H2/N2 (10/90). The extent of the cationic diffusion depends on...... temperature and duration of heat-treatments. The mechanism of the diffusion depends on the type of the gases used for the heat-treatments. In this paper we propose several possible models describing mechanisms of the cationic diffusion, and hence, of the formation of the nano-layer. We also report the effect...

  14. Optimization of acidified oil esterification catalyzed by sulfonated cation exchange resin using response surface methodology

    International Nuclear Information System (INIS)

    Highlights: • As lipid source, acidified oil are from industrial wastes for renewable energy. • The predicted conversion rate of FFAs was 75.24% under the RSM optimized conditions. • The adsorption system was employed to remove the water produced to shift the equilibrium toward ethyl ester production. • Maximum conversion rate of 98.32% was obtained using adsorption system at optimum process parameters. • Compared with tradition methods, molecular sieve dehydration method improved the conversion rate by 23.08%. - Abstract: The esterification of acidified oil with ethanol catalyzed by sulfonated cation exchange resins (SCER) was optimized using the response surface methodology (RSM). The effects of the molar ratio of ethanol to acidified oil, reaction time and catalyst loading on the conversion rate of free fatty acids (FFAs) were investigated at the temperature of the boiling point of ethanol. Results showed that the highest conversion rate of 75.24% was obtained at the molar ratio of ethanol to acidified oil of 23.2, reaction time of 8.0 h and catalyst loading of 35.0 wt.%. Moreover, the conversion rate of FFAs was increased to 98.32% by using a water adsorption apparatus under the RSM optimized conditions. Scanning electronic microscopic–energy dispersive spectrometric (SEM–EDS), X-ray diffractometric (XRD) and thermogravimetric–derivative thermogravimetric (TG–DTG) analyses confirmed that the morphology of catalysts did not change much and the mechanical and thermal stabilities were still good after the reaction. Furthermore, SCER exhibited a high catalytic activity and stability after being reused for five successive times. The fuel properties of the biodiesel were comparable to that of ASTM, EN and GB biodiesel standard

  15. Surface modification of silver nanofilms for improved perchlorate detection by surface-enhanced Raman scattering.

    Science.gov (United States)

    Hao, Jumin; Han, Mei-Juan; Li, Jinwei; Meng, Xiaoguang

    2012-07-01

    Surface-enhanced Raman scattering (SERS), as one of the most sensitive spectroscopic analysis methods, has been investigated extensively for the detection of environmental contaminants in recent years. In this work, we reported the new development of robust SERS substrates for rapid and sensitive sensing of aqueous perchlorate, a widespread environmental contaminant. The fabrication of the substrates consisted of two simple steps: (a) formation of Ag nanofilms on Cu and surface-roughened Cu foils (Ag/Cu and Ag/rCu nanofilms) using a controllable and inexpensive one-step electroless plating process, and (b) surface modification of the Ag nanofilms with cysteamine (Cys) self-assembly monolayer (SAM) (Cys-Ag/Cu and Cys-Ag/rCu substrates). Due to the strong affinity of -NH(3)(+) groups of the Cys molecules for perchlorate ions, the rapid SERS detection of perchlorate has been realized with a limit of detection (LOD) down to 5 μg L(-1) (ppb) for aqueous samples without need for drying. Various calibration curves with good linear relationships were obtained, indicating the quantification potential of SERS analysis of perchlorate using these new substrates. It was found that the neutral pH yielded the maximum SERS signals, and 85% of original sensitivity was remained in 5 days of storage time in the air, indicating the substrates are fairly stable. Within 10 regeneration-reuse cycles, the SERS signals of perchlorate kept in the range of 85-105% of the original value, verifying its reusability. PMID:22494687

  16. Surface modification of magnesium hydroxide by γ-aminopropyltriethoxysilane

    Institute of Scientific and Technical Information of China (English)

    LUO Wei; FENG Qi-ming; OU Le-ming; LIU Kun

    2008-01-01

    Magnesium hydroxide (MH), which is commonly used as a halogen-free flame retardant filler in composite materials, was modified by silanization reaction with γ-aminopropyltriethoxysilane (γ-APS) in aqueous solution at different pH values (pH range from 8.0 to 12.0). The surface properties of grafted γ-APS on MH surface as a function of solution pH value were studied using elemental analysis, Fourier transform infrared spectroscopy and zeta potential measurement. The results show that hydrolysis and condensation of γ-APS are activated in alkaline solution and lead to multilayer adsorption of γ-APS molecules on the surface of MH. The type of adsorption orientation of γ-APS on MH surface is a function of coverage density that is altered by changing solution pH value. At low coverage density (e.g.55nm-2), γ-APS molecules are preferentially adsorbed to the surface with the silicon moiety towards the surface, and increasing coverage density (e.g.90nm-2) leads to parallel orientation. At an even higher coverage density(e.g.115nm-2), γ-APS molecules bond to the surface with the amino moiety towards the surface.

  17. Laser surface modification of PET to improve biocompatibility

    International Nuclear Information System (INIS)

    In order to improve biocompatibility, the surfaces of polyethylene terephthalate obtained by irradiation with a CO2 pulsed laser in air without a photo sensitizer were studied. The complicated microstructures were obtained on the polyethylene terephthalate surface due to irradiation with various wavelengths of CO2 laser and observed by scanning electron microscope. The changes in chemical and physical properties of the irradiated polyethylene terephthalate surface were investigated by attenuated total reflectance fourier-transform infrared spectroscopy and contact angle measurements. The water drop contact angle also decreased with increasing of laser pulses. The density of peroxides formed on the irradiated polyethylene terephthalate surface were determined by iodide method. The Kr F and CO2 laser treated polyethylene terephthalate surface were compared from viewpoints of the morphology, chemical and physical properties. Graft copolymerization of acrylamide and acrylic acid onto the surface of polyethylene terephthalate were performed to improved water wettability using the CO2 pulsed laser. After laser irradiation in air, the films were placed in the aqueous solution of monomer and then heated to decompose peroxides formed onto the irradiated polyethylene terephthalate film. The grafted polyethylene terephthalate surfaces were characterized by ATR-IR spectroscopy, Sem, contact angle measurements, X-Ray photoelectron spectroscopy and energy dispersive X-Ray analysis. The compatibility of the laser irradiated polyethylene terephthalate films was examined in vitro, evaluating their capability of inducing platelet adhesion in comparison with the unmodified polyethylene terephthalate. The number of adhered platelets was determined by lactate dehydrogenase activity measurement. The morphology of adhered platelets on the polyethylene terephthalate surfaces was investigated by scanning electron microscope. The scanning electron microscope observations were consistent

  18. Chemical surface modification of poly(p-xylylene) thin films.

    Science.gov (United States)

    Herrera-Alonso, Margarita; McCarthy, Thomas J

    2004-10-12

    Electrophilic aromatic substitution reactions were studied at poly(p-xylylene) (PPX) film surface-reaction medium interfaces. The extent of the reactions (depth of penetration and degree of substitution) was determined by the interaction of the polymer with the reaction solution. Reaction with chlorosulfonic acid to produce sulfonyl chloride and sulfone functionalities occurred readily in the bulk of PPX, and yields were sensitive to time and temperature. Confinement of this reaction to the PPX surface was achieved by controlling the concentration of the acid. Functionalization of PPX with N-methylol-2-chloroacetamide in sulfuric acid to produce the chloroamidomethylated derivative occurred in high yield and was confined to the surface region of PPX. Hydrolysis of the amide to generate aminomethylated PPX was assessed by XPS and a derivatization reaction. Friedel-Crafts type chemistry (acylation and alkylation reactions) also produced functionalized surfaces, but with lower degrees of substitution than the other two reactions and was strictly surface-confined. PMID:15461504

  19. Enhanced photocatalytic activity of TiO2 by surface fluorination in degradation of organic cationic compound

    Institute of Scientific and Technical Information of China (English)

    YANG Shi-ying; CHEN You-yuan; ZHENG Jian-guo; CUI Ying-jie

    2007-01-01

    Experiments were carried out to investigate the influence of TiO2 surface fluorination on the photodegradation of a representative organic cationic compound, Methylene Blue (MB). The electropositive MB shows poor adsorption on TiO2 surface; its degradation performs a HO· radical-mediated mechanism. In the F-modified system, the kinetic reaction rate enlarged more than 2.5 fold that was attributed mainly to the accumulating adsorption of MB and the increased photogenerated hole available on the F-modified TiO2 surface.

  20. Identification of Posttranslational Modification-Dependent Protein Interactions Using Yeast Surface Displayed Human Proteome Libraries

    Science.gov (United States)

    Bidlingmaier, Scott; Liu, Bin

    2016-01-01

    The identification of proteins that interact specifically with posttranslational modifications such as phosphorylation is often necessary to understand cellular signaling pathways. Numerous methods for identifying proteins that interact with posttranslational modifications have been utilized, including affinity-based purification and analysis, protein microarrays, phage display, and tethered catalysis. Although these techniques have been used successfully, each has limitations. Recently, yeast surface-displayed human proteome libraries have been utilized to identify protein fragments with affinity for various target molecules, including phosphorylated peptides. When coupled with fluorescently activated cell sorting and high throughput methods for the analysis of selection outputs, yeast surface-displayed human proteome libraries can rapidly and efficiently identify protein fragments with affinity for any soluble ligand that can be fluorescently detected, including posttranslational modifications. In this review we compare the use of yeast surface display libraries to other methods for the identification of interactions between proteins and posttranslational modifications and discuss future applications of the technology. PMID:26060076

  1. Surface modification of implanted cardiovascular metal stents: from antithrombosis and antirestenosis to endothelialization.

    Science.gov (United States)

    Zhang, Kun; Liu, Tao; Li, Jing-An; Chen, Jun-Ying; Wang, Jian; Huang, Nan

    2014-02-01

    Driven by the complications occurring with bare metal stents and drug-eluting stents, concerns have been raised over strategies for long-term safety, with respect to preventing or inhibiting stent thrombosis, restenosis, and in-stent restenosis in particularly. Surface modification is very important in constructing a buffer layer at the interface of the organic and inorganic materials and in ultimately obtaining long-term biocompatibility. In this review, we summarize the developments in surface modification of implanted cardiovascular metal stents. This review focuses on the modification of metal stents via coating drugs or biomolecules to enhance antithrombosis, antirestenosis, and/or endothelialization. In addition, we indicate the probable future work involving the modification of the metallic blood-contacting surfaces of stents and other cardiovascular devices that are under development. PMID:23520056

  2. Effect of plasma surface modification on the biocompatibility of UHMWPE

    Energy Technology Data Exchange (ETDEWEB)

    Kaklamani, G; Chen, J; Dong, H; Stamboulis, A [School of Metallurgy and Materials, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Mehrban, N; Bowen, J; Grover, L, E-mail: a.stamboulis@bham.ac.u [School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2010-10-01

    In this paper active screen plasma nitriding (ASPN) is used to chemically modify the surface of UHMWPE. This is an unexplored and new area of research. ASPN allows the homogeneous treatment of any shape or surface at low temperature; therefore, it was thought that ASPN would be an effective technique to modify organic polymer surfaces. ASPN experiments were carried out at 120 {sup 0}C using a dc plasma nitriding unit with a 25% N{sub 2} and 75% H{sub 2} atmosphere at 2.5 mbar of pressure. UHMWPE samples treated for different time periods were characterized by nanoindentation, FTIR, XPS, interferometry and SEM. A 3T3 fibroblast cell line was used for in vitro cell culture experiments. Nanoindentation of UHMWPE showed that hardness and elastic modulus increased with ASPN treatment compared to the untreated material. FTIR spectra did not show significant differences between the untreated and treated samples; however, some changes were observed at 30 min of treatment in the range of 1500-1700 cm{sup -1} associated mainly with the presence of N-H groups. XPS studies showed that nitrogen was present on the surface and its amount increased with treatment time. Interferometry showed that no significant changes were observed on the surfaces after the treatment. Finally, cell culture experiments and SEM showed that fibroblasts attached and proliferated to a greater extent on the plasma-treated surfaces leading to the conclusion that ASPN surface treatment can potentially significantly improve the biocompatibility behaviour of polymeric materials.

  3. Effect of plasma surface modification on the biocompatibility of UHMWPE.

    Science.gov (United States)

    Kaklamani, G; Mehrban, N; Chen, J; Bowen, J; Dong, H; Grover, L; Stamboulis, A

    2010-10-01

    In this paper active screen plasma nitriding (ASPN) is used to chemically modify the surface of UHMWPE. This is an unexplored and new area of research. ASPN allows the homogeneous treatment of any shape or surface at low temperature; therefore, it was thought that ASPN would be an effective technique to modify organic polymer surfaces. ASPN experiments were carried out at 120 °C using a dc plasma nitriding unit with a 25% N(2) and 75% H(2) atmosphere at 2.5 mbar of pressure. UHMWPE samples treated for different time periods were characterized by nanoindentation, FTIR, XPS, interferometry and SEM. A 3T3 fibroblast cell line was used for in vitro cell culture experiments. Nanoindentation of UHMWPE showed that hardness and elastic modulus increased with ASPN treatment compared to the untreated material. FTIR spectra did not show significant differences between the untreated and treated samples; however, some changes were observed at 30 min of treatment in the range of 1500-1700 cm(-1) associated mainly with the presence of N-H groups. XPS studies showed that nitrogen was present on the surface and its amount increased with treatment time. Interferometry showed that no significant changes were observed on the surfaces after the treatment. Finally, cell culture experiments and SEM showed that fibroblasts attached and proliferated to a greater extent on the plasma-treated surfaces leading to the conclusion that ASPN surface treatment can potentially significantly improve the biocompatibility behaviour of polymeric materials. PMID:20876959

  4. Effect of plasma surface modification on the biocompatibility of UHMWPE

    International Nuclear Information System (INIS)

    In this paper active screen plasma nitriding (ASPN) is used to chemically modify the surface of UHMWPE. This is an unexplored and new area of research. ASPN allows the homogeneous treatment of any shape or surface at low temperature; therefore, it was thought that ASPN would be an effective technique to modify organic polymer surfaces. ASPN experiments were carried out at 120 0C using a dc plasma nitriding unit with a 25% N2 and 75% H2 atmosphere at 2.5 mbar of pressure. UHMWPE samples treated for different time periods were characterized by nanoindentation, FTIR, XPS, interferometry and SEM. A 3T3 fibroblast cell line was used for in vitro cell culture experiments. Nanoindentation of UHMWPE showed that hardness and elastic modulus increased with ASPN treatment compared to the untreated material. FTIR spectra did not show significant differences between the untreated and treated samples; however, some changes were observed at 30 min of treatment in the range of 1500-1700 cm-1 associated mainly with the presence of N-H groups. XPS studies showed that nitrogen was present on the surface and its amount increased with treatment time. Interferometry showed that no significant changes were observed on the surfaces after the treatment. Finally, cell culture experiments and SEM showed that fibroblasts attached and proliferated to a greater extent on the plasma-treated surfaces leading to the conclusion that ASPN surface treatment can potentially significantly improve the biocompatibility behaviour of polymeric materials.

  5. Atmospheric pressure plasma surface modification of carbon fibres

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Michelsen, Poul

    2008-01-01

    Carbon fibres are continuously treated with dielectric barrier discharge plasma at atmospheric pressure in various gas conditions for adhesion improvement in mind. An x-ray photoelectron spectroscopic analysis indicated that oxygen is effectively introduced onto the carbon fibre surfaces by He, He...... temperature for a month the O/C ratio at the plasma treated surfaces decreased to 0.151, which is close to that of the untreated ones. It can be attributed to the adsorption of hydrocarbon contamination at the plasma treated surfaces....

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

    International Nuclear Information System (INIS)

    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 Ra 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 Ra values ranging between ∼2 and ∼3 nm but not for those with Ra 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.

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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

  9. Surface Modification of Fire-retardant Asphalt with Silane Coupling Agent

    Institute of Scientific and Technical Information of China (English)

    CHEN Huiqiang; TANG Boming

    2012-01-01

    The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced,The optimum silane dosage was determined,and the structure and properties of the asphalt fire-retardant before and after the surface modification were characterized by infrared spectrum and thermo gravimetric analysis.The dispersion effect of asphalt fire-retardant was studied.The influence of the surface modification on the hydrophilicity and lipophilicity of the asphalt fire-retardant was analyzed.The experimental results showed that there were physical and chemical interactions between the silane coupling agent and the asphalt fire-retardant,which reduced the surface polarity of the asphalt fire retardant.The optimum silane coupling agent dosage was 0.95% of the asphalt fire retardant.The surface modification improved the thermal stability,dispersibility and lipophilicity of the asphalt fire retardant,which enhanced the compatibility between asphalt fire retardant and asphalt.

  10. 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.

  11. Surface modification of powder materials and room temperature activation of V, Ni and TiFe

    International Nuclear Information System (INIS)

    Because many properties of materials are mainly affected by the structure of surface or surface layer, surface modification is becoming more and more important in physics and material science research. The surface modifications of bulk materials by laser, ion and electron beam have been extensively investigated and achieved success in many applications. In this paper the authors report the results on the surface modification of V, Nb and TiFe by mechanical alloying with a little LaNi5, which results in room temperature activation of these powder materials. About 10g of mechanically alloyed samples were put into a chamber of H-absorption apparatus and then activated at room temperature. The morphology, structure and composition of the alloyed particles were investigated by means of SEM, X-ray diffraction, TEM and electron microprobe respectively. As a comparison, the hydrogen absorption properties of metal V activated by traditional high temperature treatment were also measured

  12. Surface modification of powder materials and room temperature activation of V, Ni and TiFe

    Energy Technology Data Exchange (ETDEWEB)

    Lue Manqi; Zhang Haifeng; Wang Yulan; Wei Wenduo (Academia Sinica, Shenyang (China). International Centre of Material Physics)

    1993-11-01

    Because many properties of materials are mainly affected by the structure of surface or surface layer, surface modification is becoming more and more important in physics and material science research. The surface modifications of bulk materials by laser, ion and electron beam have been extensively investigated and achieved success in many applications. In this paper the authors report the results on the surface modification of V, Nb and TiFe by mechanical alloying with a little LaNi[sub 5], which results in room temperature activation of these powder materials. About 10g of mechanically alloyed samples were put into a chamber of H-absorption apparatus and then activated at room temperature. The morphology, structure and composition of the alloyed particles were investigated by means of SEM, X-ray diffraction, TEM and electron microprobe respectively. As a comparison, the hydrogen absorption properties of metal V activated by traditional high temperature treatment were also measured.

  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 of Chlorella vulgaris cells using magnetite particles

    Czech Academy of Sciences Publication Activity Database

    Procházková, G.; Šafařík, Ivo; Brányik, T.

    2012-01-01

    Roč. 42, č. 2012 (2012), s. 1778-1787. ISSN 1877-7058 Institutional support: RVO:67179843 Keywords : microalgae * physicochemical approaches * surface interactions * magnetite * XDLVO theory * harvesting Subject RIV: EI - Biotechnology ; Bionics

  15. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

    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...... air are separated using a polyethylene film. The gliding arc was extended by a high speed air flow into ambient air, directed the polyester surface at an angle of approximately 30o. The ultrasonic waves were introduced vertically to the surface. After the plasma treatment using each plasma source...... without ultrasonic 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...

  16. Modification of the charge transport properties of the copper phthalocyanine/poly(vinyl alcohol) interface using cationic or anionic surfactant for field-effect transistor performance enhancement

    Science.gov (United States)

    Jastrombek, Diana; Nawaz, Ali; Koehler, Marlus; Meruvia, Michelle S.; Hümmelgen, Ivo A.

    2015-08-01

    We report on the performance enhancement of organic field-effect transistors prepared using cross-linked poly(vinyl alcohol) as gate dielectric and copper phthalocyanine as channel semiconductor through gate dielectric surface treatment. The gate dielectric surface was treated using either a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecyl sulfate (SDS). We determined the charge-carrier field-effect mobility ( μ FET) in these transistors as a function of the effective channel thickness in the channel bottleneck, near to the transistor source. When compared to the untreated devices, in the devices treated with CTAB or SDS, the channel formation occurs at lower gate voltage and the carrier mobility in the thinnest channel region, corresponding to the immediate vicinity of the insulator/semiconductor interface, is significantly higher. The surfactant treatment leads to a tenfold increase in μ FET and significant enhancement in capacitance, on/off current ratio and transconductance of the transistor.

  17. Modification of the charge transport properties of the copper phthalocyanine/poly(vinyl alcohol) interface using cationic or anionic surfactant for field-effect transistor performance enhancement

    International Nuclear Information System (INIS)

    We report on the performance enhancement of organic field-effect transistors prepared using cross-linked poly(vinyl alcohol) as gate dielectric and copper phthalocyanine as channel semiconductor through gate dielectric surface treatment. The gate dielectric surface was treated using either a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecyl sulfate (SDS). We determined the charge-carrier field-effect mobility ( μ FET) in these transistors as a function of the effective channel thickness in the channel bottleneck, near to the transistor source. When compared to the untreated devices, in the devices treated with CTAB or SDS, the channel formation occurs at lower gate voltage and the carrier mobility in the thinnest channel region, corresponding to the immediate vicinity of the insulator/semiconductor interface, is significantly higher. The surfactant treatment leads to a tenfold increase in μ FET and significant enhancement in capacitance, on/off current ratio and transconductance of the transistor. (paper)

  18. Surface modification of UHMWPE with infrared femtosecond laser

    International Nuclear Information System (INIS)

    Highlights: ► Ultra High Molecular Weight Polyethylene surface was modified with femtosecond laser pulses at 1027 nm wavelength. ► Surface roughness is increased. ► Ablation efficiency is maximum for 6 μJ pulses. ► Irradiated surfaces remain almost chemically unaltered. - Abstract: Ultra-high-molecular-weight polyethylene (UHMWPE) is a polymer with mechanical and corrosion properties, which make it appropriate for using in biomedical devices such as hip and knee prostheses. The surface morphology and chemistry of UHMWPE influence its biocompatibility. A laser with wavelength at 1027 nm delivering 450 fs pulses at a repetition rate of 1 kHz is used to modify the surface of UHMWPE samples with 0.45 μm root mean square surface roughness. Micrometric resolution is achieved with the use of a focusing lens of 0.25 NA and pulse energies of few microjoules. The study focuses in the influence of different pulse energies and pulse overlaps on the laser-induced surface roughness and ablation yield. Confocal microscopy is used to characterize changes in the morphology of the irradiated surfaces, and their chemical structure is analyzed by attenuated total reflectance infrared and Raman spectroscopies. The roughness increases as the pulse energy increases until it reaches a maximum. The ablation yield increases with the pulse energy and pulse overlap. However, the ablation yield per pulse is lower for higher pulse overlap. Pulses of 6 μJ have the highest ablation efficiency. Infrared and Raman spectra of samples irradiated with low energy pulses are similar to those of the pristine sample. However, some C=C and C=O bonds can be detected after irradiation with the highest pulse energies.

  19. Surface modification of UHMWPE with infrared femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Pradas, J.M., E-mail: jmfernandez@ub.edu [Departament de Fisica Aplicada i Optica, Universitat de Barcelona Marti i Franques 1, E-08028 Barcelona (Spain); Naranjo-Leon, S.; Morenza, J.L.; Serra, P. [Departament de Fisica Aplicada i Optica, Universitat de Barcelona Marti i Franques 1, E-08028 Barcelona (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Ultra High Molecular Weight Polyethylene surface was modified with femtosecond laser pulses at 1027 nm wavelength. Black-Right-Pointing-Pointer Surface roughness is increased. Black-Right-Pointing-Pointer Ablation efficiency is maximum for 6 {mu}J pulses. Black-Right-Pointing-Pointer Irradiated surfaces remain almost chemically unaltered. - Abstract: Ultra-high-molecular-weight polyethylene (UHMWPE) is a polymer with mechanical and corrosion properties, which make it appropriate for using in biomedical devices such as hip and knee prostheses. The surface morphology and chemistry of UHMWPE influence its biocompatibility. A laser with wavelength at 1027 nm delivering 450 fs pulses at a repetition rate of 1 kHz is used to modify the surface of UHMWPE samples with 0.45 {mu}m root mean square surface roughness. Micrometric resolution is achieved with the use of a focusing lens of 0.25 NA and pulse energies of few microjoules. The study focuses in the influence of different pulse energies and pulse overlaps on the laser-induced surface roughness and ablation yield. Confocal microscopy is used to characterize changes in the morphology of the irradiated surfaces, and their chemical structure is analyzed by attenuated total reflectance infrared and Raman spectroscopies. The roughness increases as the pulse energy increases until it reaches a maximum. The ablation yield increases with the pulse energy and pulse overlap. However, the ablation yield per pulse is lower for higher pulse overlap. Pulses of 6 {mu}J have the highest ablation efficiency. Infrared and Raman spectra of samples irradiated with low energy pulses are similar to those of the pristine sample. However, some C=C and C=O bonds can be detected after irradiation with the highest pulse energies.

  20. Control of wettability of polymers by surface roughness modification

    OpenAIRE

    Encinas, N.; Pantoja, M.; Abenojar, J.; Martínez, M. A.

    2010-01-01

    Most polymeric materials, particularly polyolefins and their derivatives, present a low surface energy which is the cause of their poor wettability and limits processes such as adhesive bonding, painting, or metalizing. Many methods have been developed and used to modify polymer surfaces for improved wetting, including mechanical treatments, wet-chemical treatments with strong acids or bases, and exposure to flames or corona discharge.In this paper the improvement of wetting properties of sev...

  1. Surface Modification of Polymeric Materials by Plasma Treatment

    OpenAIRE

    Castro Vidaurre E.F.; Achete C.A.; Gallo F.; Garcia D.; Simão R; Habert A.C.

    2002-01-01

    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, respecti...

  2. Investigation of plasma processes in surface Modification with biodiagnostic applications

    OpenAIRE

    Coyle, Conor

    2012-01-01

    Plasma enhanced chemical vapour deposition was investigated for the deposition of bioactive surfaces which can be categorised into two functions. The first is in biosensor applications, immunoassay biodevices have been researched considerably but significant problems remain in particular non-specific adsorption. This work demonstrates a new method of reducing the non specific adsorption on the surface of cyclo olefin polymers for use as immunoassay biodevices. PECVD deposition of a silico...

  3. Atomic and molecular layer deposition for surface modification

    International Nuclear Information System (INIS)

    Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al2O3 due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO2. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt

  4. Atomic and molecular layer deposition for surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Sievänen, Jenni; Salo, Erkki; Heikkilä, Pirjo; Kenttä, Eija [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland); Johansson, Leena-Sisko, E-mail: leena-sisko.johansson@aalto.fi [Aalto University, School of Chemical Technology, Department of Forest Products Technology, PO Box 16100, FI‐00076 AALTO (Finland); Koskinen, Jorma T.; Harlin, Ali [VTT Technical Research Centre of Finland, PO Box 1000, FI‐02044 VTT (Finland)

    2014-06-01

    Atomic and molecular layer deposition (ALD and MLD, respectively) techniques are based on repeated cycles of gas–solid surface reactions. A partial monolayer of atoms or molecules is deposited to the surface during a single deposition cycle, enabling tailored film composition in principle down to molecular resolution on ideal surfaces. Typically ALD/MLD has been used for applications where uniform and pinhole free thin film is a necessity even on 3D surfaces. However, thin – even non-uniform – atomic and molecular deposited layers can also be used to tailor the surface characteristics of different non-ideal substrates. For example, print quality of inkjet printing on polymer films and penetration of water into porous nonwovens can be adjusted with low-temperature deposited metal oxide. In addition, adhesion of extrusion coated biopolymer to inorganic oxides can be improved with a hybrid layer based on lactic acid. - Graphical abstract: Print quality of a polylactide film surface modified with atomic layer deposition prior to inkjet printing (360 dpi) with an aqueous ink. Number of printed dots illustrated as a function of 0, 5, 15 and 25 deposition cycles of trimethylaluminum and water. - Highlights: • ALD/MLD can be used to adjust surface characteristics of films and fiber materials. • Hydrophobicity after few deposition cycles of Al{sub 2}O{sub 3} due to e.g. complex formation. • Same effect on cellulosic fabrics observed with low temperature deposited TiO{sub 2}. • Different film growth and oxidation potential with different precursors. • Hybrid layer on inorganic layer can be used to improve adhesion of polymer melt.

  5. Surface modification of UHMWPE with infrared femtosecond laser

    Science.gov (United States)

    Fernández-Pradas, J. M.; Naranjo-León, S.; Morenza, J. L.; Serra, P.

    2012-09-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) is a polymer with mechanical and corrosion properties, which make it appropriate for using in biomedical devices such as hip and knee prostheses. The surface morphology and chemistry of UHMWPE influence its biocompatibility. A laser with wavelength at 1027 nm delivering 450 fs pulses at a repetition rate of 1 kHz is used to modify the surface of UHMWPE samples with 0.45 μm root mean square surface roughness. Micrometric resolution is achieved with the use of a focusing lens of 0.25 NA and pulse energies of few microjoules. The study focuses in the influence of different pulse energies and pulse overlaps on the laser-induced surface roughness and ablation yield. Confocal microscopy is used to characterize changes in the morphology of the irradiated surfaces, and their chemical structure is analyzed by attenuated total reflectance infrared and Raman spectroscopies. The roughness increases as the pulse energy increases until it reaches a maximum. The ablation yield increases with the pulse energy and pulse overlap. However, the ablation yield per pulse is lower for higher pulse overlap. Pulses of 6 μJ have the highest ablation efficiency. Infrared and Raman spectra of samples irradiated with low energy pulses are similar to those of the pristine sample. However, some Cdbnd C and Cdbnd O bonds can be detected after irradiation with the highest pulse energies.

  6. Modification of surfaces following plasma implantation of helium

    International Nuclear Information System (INIS)

    The surface and sub-surface regions of silicon and a range of titanium- and vanadium-based metals have been modified by implantation of helium at energies of 20-50 keV, using the Plasma Immersion Ion Implantation (PI3) facility at ANSTO. In the case of silicon, the resulting structure has been altered further, either by thermal annealing, or by thermal annealing following the application of a thin, sputtered, film of gold onto the surface. For the metals, the implanted structure has been oxidised in several ways; thermally, anodically, and by plasma implantation. Surfaces modified in these ways might be expected to have unique chemical and physical properties. They have been investigated by a range of techniques including electron microscopy, Raman spectroscopy, Rutherford backscattering spectrometry, and nuclear reaction analysis. The structure and phases of oxides developed on plasma-implanted metals are compared with those on unimplanted, but otherwise identically treated, metals. Corresponding results for helium-ion implantation at higher energies are also presented. It is shown that implantation can affect the blend of oxide phases at the surface and the degree of oxidation

  7. Fabrication of superhydrophobic vanadium pentoxide nanowires surface by chemical modification

    International Nuclear Information System (INIS)

    Vanadium pentoxide (V2O5) nanowires have been synthesized on Au-coated Si substrates by a physical vapor deposition process. The synthesized nanowires are randomly oriented with a diameter around 40-200 nm and length of several micrometers. The crystalline structure of the nanowires analyzed by using X-ray diffraction and Raman spectroscopy corresponds to single crystalline orthorhombic V2O5 phase with [0 0 1] growth orientation. The transmission electron microscopy and energy-dispersive X-ray analysis suggests a possible vapor-solid (VS) growth mechanism for the V2O5 nanowires. A self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) was deposited on the V2O5 nanowires to obtain superhydrophobic V2O5 nanowire surfaces with water contact angle (CA) of 157.5°. The superhydrophobic behavior is attributed to the high surface roughness provided by the nanowire surface and low surface energy due to SAM layer deposition. The impact dynamics of water droplets impinging on the superhydrophobic surface is also investigated.

  8. Study on Glow Discharge Plasma Used in Polyester Surface Modification

    Science.gov (United States)

    Liu, Wenzheng; Lei, Xiao; Zhao, Qiang

    2016-01-01

    To achieve an atmospheric pressure glow discharge (APGD) in air and modify the surface of polyester thread using plasma, the electric field distribution and discharge characteristics under different conditions were studied. We found that the region with a strong electric field, which was formed in a tiny gap between two electrodes constituting a line-line contact electrode structure, provided the initial electron for the entire discharge process. Thus, the discharge voltage was reduced. The dielectric barrier of the line-line contact electrodes can inhibit the generation of secondary electrons. Thus, the transient current pulse discharge was reduced significantly, and an APGD in air was achieved. We designed double layer line-line contact electrodes, which can generate the APGD on the surface of a material under treatment directly. A noticeable change in the surface morphology of polyester fiber was visualized with the aid of a scanning electron microscope (SEM). Two electrode structures - the multi-row line-line and double-helix line-line contact electrodes - were designed. A large area of the APGD plasma with flat and curved surfaces can be formed in air using these contact electrodes. This can improve the efficiency of surface treatment and is significant for the application of the APGD plasma in industries.

  9. Femtosecond laser modification of titanium surfaces: direct imprinting of hydroxylapatite nanopowder and wettability tuning via surface microstructuring

    Science.gov (United States)

    Ionin, Andrey A.; Kudryashov, Sergey I.; Makarov, Sergey V.; Saltuganov, Pavel N.; Seleznev, Leonid V.; Sinitsyn, Dmitry V.; Golosov, Evgene V.; Goryainov, Artem A.; Kolobov, Yury R.; Kornieieva, Kateryna A.; Skomorokhov, Andrei N.; Ligachev, Alexander E.

    2013-04-01

    Femtosecond laser modification of titanium surfaces was performed to produce microstructured hydrophilic and biocompatible surface layers. Biocompatible nano/microcoatings were prepared for the first time by dry femtosecond laser imprinting of hydroxylapatite nano/micropowder onto VT6 titanium surfaces. In these experiments HAP was first deposited onto the titanium surfaces and then softly imprinted by multiple femtosecond laser pulses into the laser-melted surface metal layer. The surface relief was modified at the nano- and microscales depending on the incident laser fluence and sample scanning speed. Wetting tests demonstrated that the wetting properties of the pristine Ti surface can be tuned through its laser modification in both the hydrophobic and hydrophilic directions.

  10. Femtosecond laser modification of titanium surfaces: direct imprinting of hydroxylapatite nanopowder and wettability tuning via surface microstructuring

    International Nuclear Information System (INIS)

    Femtosecond laser modification of titanium surfaces was performed to produce microstructured hydrophilic and biocompatible surface layers. Biocompatible nano/microcoatings were prepared for the first time by dry femtosecond laser imprinting of hydroxylapatite nano/micropowder onto VT6 titanium surfaces. In these experiments HAP was first deposited onto the titanium surfaces and then softly imprinted by multiple femtosecond laser pulses into the laser-melted surface metal layer. The surface relief was modified at the nano- and microscales depending on the incident laser fluence and sample scanning speed. Wetting tests demonstrated that the wetting properties of the pristine Ti surface can be tuned through its laser modification in both the hydrophobic and hydrophilic directions. (letter)

  11. Modification of polytetrafluoroethylene surfaces using H2S plasma treatment

    Science.gov (United States)

    Vesel, Alenka; Kovac, Janez; Zaplotnik, Rok; Modic, Martina; Mozetic, Miran

    2015-12-01

    A process for modifying the surface properties of polytetrafluoroethylene (PTFE) polymer using sulfur-containing gaseous plasma is presented in this paper. Samples of PTFE foils were treated in pure H2S gaseous plasma sustained by an electrode-less radio-frequency discharge in the E-mode. The samples were kept at a floating potential. X-ray photoelectron spectroscopy, secondary ion mass spectrometry and atomic force microscopy were used to determine the evolution of the surface functionalities and morphology. An extremely thin film of chemically bonded sulfur was formed on the surface after a few seconds of plasma treatment, whereas a treatment duration of more than a minute resulted in the deposition of pure sulfur. The deposited film remained as thin as a few nanometers, even after half an hour of treatment.

  12. Simulation of liquid crystals. Disclinations and surface modification

    CERN Document Server

    Downton, M

    2001-01-01

    In this thesis we investigate the behaviour of molecular models liquid crystals in several different situations. Basic introductory material on liquid crystals and computer simulations is discussed in the first two chapters, we then discuss the research. The third chapter investigates the interaction between a liquid crystal and a modified surface. A confined system of hard spherocylinders in a slab geometry is examined. The surface consists of planar hard walls with elongated molecules grafted perpendicularly onto them. The concentration of grafted molecules is varied to give different surfaces. Several different behaviours are found including planar, homeotropic and tilted anchorings of the liquid crystal. Molecular dynamics simulations of a nematic liquid crystal in slab geometry with twisted boundary conditions are performed. By arranging the initial configuration suitably it is possible to create a simulation cell with two regions of opposite twist separated by a strength half disclination line. The prop...

  13. Controlled mechnical modification of manganite surface with nanoscale resolution

    International Nuclear Information System (INIS)

    We investigated the surfaces of magnetoresistive manganites, La1−xCaxMnO3 and La2-2xSr1+2xMn2O7, using a combination of ultrahigh vacuum conductive, electrostatic and magnetic force microscopy methods. Scanning as-grown film with a metal tip, even with zero applied bias, was found to modify the surface electronic properties such that in subsequent scans, the conductivity is reduced below the noise level of conductive probe microscopy. Scanned areas also reveal a reduced contact potential difference relative to the pristine surface by ∼0.3 eV. We propose that contact-pressure of the tip modifies the electrochemical potential of oxygen vacancies via the Vegard effect, causing vacancy motion and concomitant changes of the electronic properties. (paper)

  14. Laser produced coatings and surface modifications for medical implants

    International Nuclear Information System (INIS)

    Lasers can be an effective tool for tailoring the surface of medical implants. Laser irradiation can modify the surface wettability, bioactivity and its capacity to absorb proteins. By using appropriate energies and wavelengths, also the topographical features at macro, micro and nano level can be shaped in order to adapt to cells, extracellular matrices and orientation of ligand molecules. Pulsed laser deposition can produce nanometer thick, dense and well adhering CaP coatings with extremely fine control of chemistry and crystallinity. No further thermal annealing is needed. In-vitro and in-vivo experiments with different cells and animals models have demonstrated similar or better osseointegration of laser deposited coatings compared to the commercial available plasma sprayed ones. Ultraviolet lasers can successfully chemically functionalize the surface of implants, and femtosecond laser can drill polymer plates or meshes for tissue engineering applications.

  15. Laser produced coatings and surface modifications for medical implants

    Science.gov (United States)

    León, B.

    2010-11-01

    Lasers can be an effective tool for tailoring the surface of medical implants. Laser irradiation can modify the surface wettability, bioactivity and its capacity to absorb proteins. By using appropriate energies and wavelengths, also the topographical features at macro, micro and nano level can be shaped in order to adapt to cells, extracellular matrices and orientation of ligand molecules. Pulsed laser deposition can produce nanometer thick, dense and well adhering CaP coatings with extremely fine control of chemistry and crystallinity. No further thermal annealing is needed. In-vitro and in-vivo experiments with different cells and animals models have demonstrated similar or better osseointegration of laser deposited coatings compared to the commercial available plasma sprayed ones. Ultraviolet lasers can successfully chemically functionalize the surface of implants, and femtosecond laser can drill polymer plates or meshes for tissue engineering applications.

  16. Biomolecular modification of zirconia surfaces for enhanced biocompatibility

    International Nuclear Information System (INIS)

    Yttria-tetragonal zirconia polycrystal (Y-TZP) is a preferred biomaterial due to its good mechanical properties. In order to improve the biocompatibility of zirconia, RGD-peptide derived from extracellular matrix proteins was employed to modify the surface of Y-TZP to promote cell adhesion in this study. The surface of Y-TZP specimens was first modified using a hydrothermal method for different lengths of time. The topographies of modified Y-TZP specimens were analyzed by contact angle, XRD, FTIR, AFM, and FE-SEM. The mechanical properties were evaluated using Vickers hardness and three point bending strength. Then, the RGD-peptide was immobilized on the surface of the Y-TZP by chemical treatment. These RGD-peptide immobilized Y-TZP specimens were characterized by FTIR and AFM, and then were cocultured with MG-63 osteoblast cells for biocompatibility assay. The cell morphology and proliferation were evaluated by SEM, WST-1, and ALP activity assay. The XRD results indicated that the phase transition, from tetragonal phase to monoclinic phase, was increased with a longer incubation time of hydrothermal treatment. However, there were no significant differences in mechanical strengths after RGD-peptide was successfully grafted onto the Y-TZP surface. The SEM images showed that the MG-63 cells appeared polygonal, spindle-shaped, and attached on the RGD-peptide immobilized Y-TZP. The proliferation and cellular activities of MG-63 cells on the RGD-peptide immobilized Y-TZP were better than that on the unmodified Y-TZP. From the above results, the RGD-peptide can be successfully grafted onto the hydrothermal modified Y-TZP surface. The RGD-peptide immobilized Y-TZP can increase cell adhesion, and thus, improve the biocompatibility of Y-TZP. - Highlights: • Covalent bonding between peptide and Y-TZP was proposed. • Stable biomimetic structures produced on the surface of zirconia. • The biocompatibility was improved

  17. FAMA project: upgrade of channels for surface materials modification

    International Nuclear Information System (INIS)

    Project FAMA is related to the construction of the low energy part of the TESLA Accelerator Installation (TAI) in the Vinca Institute of Nuclear Sciences (Belgrade) and is intended for modification and analysis of materials by ion beams. FAMA includes three machines and six experimental channels. The machines are: a heavy ion source - the M1 machine, a light ion source - the M2 machine, and a small isochronous cyclotron - the M3 machine. The calculations for optimization of low energy channels are carried out. Optimum modes of transportation of the ion beams generated by sources M1 and M2 are fitted. For the purpose of reduction of losses in the channel it is offered to limit currents from the ion source M2. For increase in intensity at target of beams from ion source M1 it is offered to use the solenoid and a doublet of quadrupoles instead of a triplet. Necessity of a masking of beams of heavy ions is proved. Transportation efficiency is close to 100% in all considerable cases

  18. Crack path and fracture surface modifications in cement composites

    Directory of Open Access Journals (Sweden)

    Sajjad Ahmad

    2015-10-01

    Full Text Available There is a tremendous increase in the use of high strength and high performance self-consolidating cementitious composites due to their superior workability and mechanical strengths. Cement composites are quasi-brittle in nature and possess extremely low tensile strength as compared to their compressive strength. Due to the low tensile strength capacity, cracks develop in cementitious composites due to the drying shrinkage, plastic settlements and/or stress concentrations (due to external restrains and/or applied stresses etc. These cracks developed at the nanoscale may grow rapidly due to the applied stresses and join together to form micro and macro cracks. The growth of cracks from nanoscale to micro and macro scale is very rapid and may lead to sudden failure of the cement composites. The present paper reports the modifications in the crack growth pattern of the high performance cement composites to achieve enhanced ductility and toughness. The objective was accomplished by the incorporation of the micro sized inert particulates in the cement composite matrix. The results indicate that the incorporation of micro sized inert particles acted as the obstacles in the growth of the cracks thus improving the ductility and the energy absorption capacity of the self-consolidating cementitious composites.

  19. Laser surface modification of Ti implants to improve osseointegration

    International Nuclear Information System (INIS)

    Commercially Pure Titanium foils, were irradiated using a pulsed Nd:YAG laser under ambient air, in order to produce and characterize a well controlled surface texture (roughness and waviness) that enhances osseointegration. To study the 'peri-implant' reparative process response, the laser treated Ti foils were implanted in the tibia of 10 male Wistar rats. At 14 days post-implantation, the histological analysis showed a tendency to more bone formation compared to the untreated control implants. The formation of a layer of TiN on the surface and the obtained roughness, have been demonstrated to improve bone response

  20. Laser surface modification of Ti implants to improve osseointegration

    Energy Technology Data Exchange (ETDEWEB)

    Marticorena, M [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Corti, G [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Olmedo, D [Catedra de Anatomia Patologica, Facultad de Odontologia, Universidad de Buenos Aires. Marcelo T. de Alvear 2142, 2 piso Sector ' A' , 1122 Buenos Aires (Argentina); Guglielmotti, M B [Catedra de Anatomia Patologica, Facultad de Odontologia, Universidad de Buenos Aires. Marcelo T. de Alvear 2142, 2 piso Sector ' A' , 1122 Buenos Aires (Argentina); Duhalde, S [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina)

    2007-04-15

    Commercially Pure Titanium foils, were irradiated using a pulsed Nd:YAG laser under ambient air, in order to produce and characterize a well controlled surface texture (roughness and waviness) that enhances osseointegration. To study the 'peri-implant' reparative process response, the laser treated Ti foils were implanted in the tibia of 10 male Wistar rats. At 14 days post-implantation, the histological analysis showed a tendency to more bone formation compared to the untreated control implants. The formation of a layer of TiN on the surface and the obtained roughness, have been demonstrated to improve bone response.

  1. Application of plasmas to formation and modification of surfaces

    International Nuclear Information System (INIS)

    A brief introductory review is presented on formation of surface layers (films) by utilizing plasma mediums. The discussion covers the applications in electronic industries, protective and hard surface layers, such as titanium nitride and also the applications in production of solar cells. Finally, a discussion is presented on construction of a plasma reactor in which the plasma density and temperature are controllable in a wide range of operational parameters. This plasma source utilizes a discharge by electron beam, and is considered to be more controllable and functionalbe than the conventional plasma sources by other discharge mechanisms

  2. Modification of optical properties of copper surfaces by ion bombardment

    International Nuclear Information System (INIS)

    Influence of ion bombardment by N2+, N2+ and D+ ions on optical properties of copper films evaporated on single crystal silicon wafer and samples of balk Cu was studied. Microrelief of surface of the copper samples was studied by optical microscopy. It was found that principal incidence angle and optical conductivity of Cu subsurface layer decrease after nitrogen ion bombardment. Additional irradiation by N2+ ions does not improve corrosion stability of Cu films. It was obtained that interaction of D+ ions with subsurface layer of Cu increases the roughness of surface and essentially changes the spectra of optical conductivity

  3. Laser surface modification of Ti implants to improve osseointegration

    Science.gov (United States)

    Marticorena, M.; Corti, G.; Olmedo, D.; Guglielmotti, M. B.; Duhalde, S.

    2007-04-01

    Commercially Pure Titanium foils, were irradiated using a pulsed Nd:YAG laser under ambient air, in order to produce and characterize a well controlled surface texture (roughness and waviness) that enhances osseointegration. To study the 'peri-implant' reparative process response, the laser treated Ti foils were implanted in the tibia of 10 male Wistar rats. At 14 days post-implantation, the histological analysis showed a tendency to more bone formation compared to the untreated control implants. The formation of a layer of TiN on the surface and the obtained roughness, have been demonstrated to improve bone response.

  4. Precipitation evolution and surface modification of magnesium alloys

    Directory of Open Access Journals (Sweden)

    T. Tański

    2013-11-01

    Full Text Available Purpose: The purpose of this publication is to present the results of own long-term research summarising the experience concerning as casting magnesium alloys, and in especially a thermal analysis describing the process of alloys crystallisation, standard heat treatment according to the occurring phase transitions and precipitation processes, surface treatment with the CVD and PVD methods, laser surface treatment of surface layers, as well as using the methods of Computer Materials Science. Design/methodology/approach: The research concerned in the first place an analysis of Mg-Al-Zn alloys crystallisation kinetics. Optimisation investigations for heat treatment conditions taking into consideration different cooling mediums were performed in order to identify fully the structure of the investigated magnesium casting alloys. Investigations were carried out of the structure and properties of coatings produced with the CVD and PVD methods on the investigated Mg-Al-Zn alloys. The last stage of investigating the presented Mg-Al-Zn alloys applied to laser surface treatment enabling to produce a quasi-composite structure of MMCs characterised by the gradient of phase composition as well as functional properties by feeding hard ceramic particles, in particular carbides and oxides, into the surface of the materials produced. Findings: Valuable and original results were achieved based on the broad scope of the research performed both, in cognitive and applicational terms, concentrated mainly on the analysis and influence of chemical composition and technological heat and surface treatment processes on the structure and properties of the investigated alloys. Practical implications: The properties of the core and surface layer of the part produced can be customised most advantageously by selecting the part’s material and its structure and properties formation processes appropriately along with the surface layer type and technology ensuring the required

  5. Mapping physicochemical surface modifications of flame-treated polypropylene

    Directory of Open Access Journals (Sweden)

    S. Farris

    2014-04-01

    Full Text Available The aim of this work was to investigate how the surface morphology of polypropylene (PP is influenced by the surface activation mediated by a flame obtained using a mixture of air and propane under fuel-lean (equivalence ratio φ = 0.98 conditions. Morphological changes observed on flamed samples with smooth (S, medium (M, and high (H degree of surface roughness were attributed to the combined effect of a chemical mechanism (agglomeration and ordering of partially oxidized intermediate-molecular-weight material with a physical mechanism (flattening of the original roughness by the flame’s high temperature. After two treatments, the different behavior of the samples in terms of wettability was totally reset, which made an impressive surface energy of ~43 mJ•m–2 possible, which is typical of more hydrophilic polymers (e.g., polyethylene terephthalate – PET. In particular, the polar component was increased from 1.21, 0.08, and 0.32 mJ•m–2 (untreated samples to 10.95, 11.20, and 11.17 mJ•m–2 for the flamed samples S, M, and H, respectively, an increase attributed to the insertion of polar functional groups (hydroxyl and carbonyl on the C–C backbone, as demonstrated by the X-ray photoelectron spectroscopy results.

  6. "Click & seed" approach to the biomimetic modification of material surfaces

    Czech Academy of Sciences Publication Activity Database

    Proks, Vladimír; Jaroš, J.; Pop-Georgievski, Ognen; Kučka, Jan; Popelka, Štěpán; Dvořák, P.; Hampl, A.; Rypáček, František

    Prague : Institute of Macromolecular Chemistry AS CR, 2012. ML4. ISBN 978-80-85009-73-6. [Workshop "Career in Polymers" /4./. 29.06.2012-30.06.2012, Prague] Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : bioactive surfaces * click and seed Subject RIV: CD - Macromolecular Chemistry

  7. Surface modification of polyvalent element-containing glasses

    International Nuclear Information System (INIS)

    Seven soda-lime silicate glasses, each of which contains one of the following polyvalent metals: Fe, Mn, Cu, Ce, Ti, V, and Cr, are oxidized in air and reduced in H2/N2 (1/99) at their respective glass transition temperature for some period. A crystalline oxide surface layer is created on the glasses (except the vanadium-bearing glass) under the oxidizing condition, since the metallic ions are oxidized from lower to higher valence state, and thereby calcium ions diffuse outward and react with oxygen ions. In contrast, a silica-rich surface layer is created on the glasses under the reducing condition, since sodium and calcium ions diffuse inward. It is found that the extents of both outward and inward diffusions strongly depend on the type of the polyvalent ions for the same conditions of heat-treatment. Out of the seven polyvalent metals studied in this work, copper induces the highest extent of both the inward and outward diffusion, and hence, the thickest surface layer of both amorphous silica and crystalline alkaline earth oxides. The oxide layer lowers the onset temperature of the primary crystallization. The silica-rich surface layer enhances the chemical resistance of the glass in a hot basic solution.

  8. Nonlinear Effects of Laser Surface Modification of Ore Minerals

    Directory of Open Access Journals (Sweden)

    N.A. Leonenko

    2015-12-01

    Full Text Available The effect of continuous laser radiation on complex ore minerals objects containing gold, not extracted by monerd methods was investigated. It was established the formation of different structural surfaces of gold, revealed general patterns of sintering and concentration of sub-micron gold.

  9. Local solid-state modification of nanopore surface charges

    CERN Document Server

    Kox, Ronald; Chen, Chang; Arjmandi, Nima; Lagae, Liesbet; Borghs, Gustaaf; 10.1088/0957-4484/21/33/335703

    2012-01-01

    The last decade, nanopores have emerged as a new and interesting tool for the study of biological macromolecules like proteins and DNA. While biological pores, especially alpha-hemolysin, have been promising for the detection of DNA, their poor chemical stability limits their use. For this reason, researchers are trying to mimic their behaviour using more stable, solid-state nanopores. The most successful tools to fabricate such nanopores use high energy electron or ions beams to drill or reshape holes in very thin membranes. While the resolution of these methods can be very good, they require tools that are not commonly available and tend to damage and charge the nanopore surface. In this work, we show nanopores that have been fabricated using standard micromachning techniques together with EBID, and present a simple model that is used to estimate the surface charge. The results show that EBID with a silicon oxide precursor can be used to tune the nanopore surface and that the surface charge is stable over a...

  10. Modification of metallic surfaces by positive ion bombardment

    International Nuclear Information System (INIS)

    Reported are the fundamentals and recent advances in the use of ion implantation techniques and gaseous emissions to modify metal surfaces. The physical phenomena involved, the necessary equipment and some applications which have been successful on an industrial scale are described. (Author). 13 refs, 1 fig

  11. On-line monitoring of poly dimethylsiloxane surface modification using the photothermal deflection technique

    International Nuclear Information System (INIS)

    Over the last decade, there has been particular interest in surface modification of biomaterials with regard to understanding the importance of surface characterization. This paper reports the use of photothermal deflection (PTD) technique to monitor modifications in poly dimethylsiloxane (PDMS) surface induced following laser treatments. The FTIR results are in agreement with PTD results, indicating that no structural changes occurred using Argon laser up to 180 s and 200 mW at 454, 488 and 514 nm wavelengths. However, with CO2 laser some physical and chemical changes occurred which are monitored by PTD technique and proved by SEM images

  12. 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. PMID:27089532

  13. Surface modification of poly (vinyl chloride) by long-distance and direct argon RF plasma

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper reports the effects of long- distance and direct argon radio frequency (RF) plasma surface treatment on polyvinyl chloride (PVC) films in terms of changes in surface wettability and surface chemistry. The surface properties are characterized by the water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The mechanism is further analyzed and the role of all kinds of active species, e.g. electrons, ions and free radicals involved in plasma surface modification is further evaluated. Results show that the long-distance and direct RF plasma treatments modify the PVC surface in morphology and composition, and both modifications cause surface oxidation of PVC films, in the forming of functional groups enhancing polymer wettability. The effect of the long-distance argon RF plasma is more notable. This suggests that long-distance argon RF plasma could restrain the ion and electron eroding effect and enhance free radical reaction.

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

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki;

    2009-01-01

    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...... the studied materials. The proposed water mist treatment technique appears to be a robust, rapid, and promising tool for the improvement of the technological properties of pharmaceutical powders.......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 by a...

  15. Surface modification of nanoparticles for radiation curable acrylate clear coatings

    Science.gov (United States)

    Bauer, F.; Gläsel, H.-J.; Hartmann, E.; Bilz, E.; Mehnert, R.

    2003-08-01

    To obtain transparent, scratch and abrasion resistant coatings a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. 29SiMAS NMR and MALDI-TOF mass spectrometry were employed to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl- and n-propyl-trimethoxysilane. In accordance with NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. A ladder-like structure of bound polysiloxanes is proposed rather than a simplified picture of tridentate silane bonding. Hence, silane coupling agents do not only modify the chemical nature of the filler surface but also strongly effect the rheological properties of the acrylate nanodispersions.

  16. Inexpensive laser-induced surface modification in bismuth thin films

    International Nuclear Information System (INIS)

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD–DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters

  17. Inexpensive laser-induced surface modification in bismuth thin films

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, A. Reyes [Facultad de Ciencias, Universidad Autónoma del Estado de México, Carretera Toluca, Ixtlahuaca Kilómetro 15.5, C.P. 50200 Edo. de México (Mexico); Hautefeuille, M., E-mail: mathieu_h@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Circuito Exterior S/N, Coyoacán, Ciudad Universitaria, C.P. 04510 D.F. Mexico (Mexico); García, A. Esparza [Fotofísica y Películas Delgadas, Departamento de Tecnociencias, CCADET-UNAM, Circuito exterior s/n C.P. 04510 Cd. Universitaria, D.F. Mexico (Mexico); Mejia, O. Olea [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, Km 14.5, Unidad El Rosedal, 50200 San Cayetano, Estado de México (Mexico); López, M.A. Camacho [Facultad de Química, Universidad Autónoma del Estado de México, Tollocan s/n, esq. Paseo Colón, Toluca, Estado de México 50110 (Mexico)

    2015-05-01

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD–DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters.

  18. Surface Modifications of Polyester Films by Ammonia Plasma

    Science.gov (United States)

    Narushima, Kazuo; Yamashita, Nanami; Fukuoka, Megumi; Inagaki, Norihiro; Isono, Yoshihiro; Islam, Mohammed Rafiqul

    2007-07-01

    Effects of treatment using ammonia plasma on poly(lactic acid) (PLA), poly(ethylene terephthalate) (PET), and liquid-crystal polymer (LCP) were investigated to elucidate differences related to polymer structures and the mode of introduction of nitrogen functional groups onto the polyester surfaces. Nitrogen functional groups were introduced into PET and LCP, but were not introduced into PLA. Those results indicate reductions in the contact angle for PET and LCP. No decrease in the contact angle was observed for PLA. Reasons for differences in attachment of nitrogen functional groups by ammonia plasma processing on polyester surfaces were discussed. The respective actions of active species were investigated for radicals, electrons, and ions in plasma.

  19. Surface modification of nanoparticles for radiation curable acrylate clear coatings

    International Nuclear Information System (INIS)

    To obtain transparent, scratch and abrasion resistant coatings a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. 29SiMAS NMR and MALDI-TOF mass spectrometry were employed to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl- and n-propyl-trimethoxysilane. In accordance with NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. A ladder-like structure of bound polysiloxanes is proposed rather than a simplified picture of tridentate silane bonding. Hence, silane coupling agents do not only modify the chemical nature of the filler surface but also strongly effect the rheological properties of the acrylate nanodispersions

  20. SURFACE MODIFICATION AND CHARACTERIZATIONS OF TiO2 NANOPARTICLE

    OpenAIRE

    GUOHUI LI

    2009-01-01

    Nanosized titanium dioxide particles were engrafted with butyltitanate coupling agent and methylmethacrylate monomer, and the obtained nanocomposite was characterized by Fourier transform infrared spectra and sedimentation test. Ultraviolet-visible light spectroscopy was used to study the differences and effectiveness of the coated and uncoated titanium dioxide, respectively. The results showed that polymethacrylate chain was engrafted on the surface of nanosized titanium dioxide and the surf...

  1. Cathodic carbon peroxidation process. Surface modifications through oxygen bonding

    OpenAIRE

    Simonet, Jacques

    2013-01-01

    The reduction of oxygen of the air at carbon electrodes in organic aprotic polar solvents in the presence of organic electrophiles such as alkyl iodides may reveal the formation of films of surface-attached alkyl peroxides. Electrochemical charge of carbons (glassy carbon, graphite, industrial coke) in the presence of tetraalkylammonium salt TAAX permits the building of poly-nucleophilic materials that may spontaneously react with air during the work up. This way, a TAA+ hydroperoxydate layer...

  2. Surface modification of stainless steel by carbon/nitrogen implantation

    Czech Academy of Sciences Publication Activity Database

    Jirásková, Yvonna; Schneeweiss, Oldřich; Havlíček, Stanislav; Blawert, C.; Kalvelage, H.

    2001-01-01

    Roč. 51, č. 7 (2001), s. 693-701. ISSN 0011-4626. [International Colloquium "Mössbauer Spectroscopy in Material Science". Velké Losiny, 03.09.2000-08.09.2000] R&D Projects: GA MŠk OC 516.60; GA MŠk ME 373 Institutional research plan: CEZ:AV0Z2041904 Keywords : surface * phase analysis * hardness Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.345, year: 2001

  3. Synthesis and Surface Modification of CdTe Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    CdTe nanocrystals were prepared in aqueous solution via the reaction between Cd2+ and NaHTe in the presence of mercaptoacetic acid. Interactions between CdTe nanocrystals and phenylalanine were formed via electrostatic/coordinate self-assembly. The photoluminescence intensity of CdTe nanocrystals was improved obviously. The interaction mechanism was discussed and was considered to be surface passivation.

  4. Carbon spheres surface modification and dispersion in polymer matrix

    International Nuclear Information System (INIS)

    Highlights: ► Vinyl groups were grafted onto the surface of CSs by acryloyl chloride. ► Vinyl-functionalized CSs were dispersed well in organic solvent. ► Non-covalent functionalization was used to functionalize the surface of CSs. ► Functionalized CSs dispersed uniformly in the PMMA matrix with good compatibility. - Abstract: Polymer/carbon spheres (CSs) composite materials, in which polymer was used as continuous phase and CSs as dispersed phase, were synthesized by in situ bulk polymerization. In order to improve CSs dispersibility in polymer matrix and compatibility with polymer matrix, the functional double bonds were introduced onto the surface of CSs by covalent and non-covalent method. Covalent functionalization was accompolished through mixed acid oxidation and subsequent reaction with acryloyl chloride. Field-emission scanning electron microscopy, Fourier-transform Infrared spectrometry and thermogravimetry were used to characterize the morphology, structure and effect of functionalization of CSs. Vinyl-functionalized CSs by acryloyl chloride were well dispersed in organic solvents, such as DMF, acetone and chloroform. Non-covalent functionalization by surfactant was accompolished by electrostatic interaction. Covalent and non-covalent functionalization enabled CSs to be homogeneously dispersed in poly(methyl methacrylate) (PMMA) matrix with good compatibility. These studies lay the foundation of preparing the non-close packed three-dimensional carbon-based photonic crystals.

  5. Surface modification of nanoporous alumina membranes by plasma polymerization

    International Nuclear Information System (INIS)

    The deposition of plasma polymer coatings onto porous alumina (PA) membranes was investigated with the aim of adjusting the surface chemistry and the pore size of the membranes. PA membranes from commercial sources with a range of pore diameters (20, 100 and 200 nm) were used and modified by plasma polymerization using n-heptylamine (HA) monomer, which resulted in a chemically reactive polymer surface with amino groups. Heptylamine plasma polymer (HAPP) layers with a thickness less than the pore diameter do not span the pores but reduce their diameter. Accordingly, by adjusting the deposition time and thus the thickness of the plasma polymer coating, it is feasible to produce any desired pore diameter. The structural and chemical properties of modified membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray electron spectroscopy (XPS). The resultant PA membranes with specific surface chemistry and controlled pore size are applicable for molecular separation, cell culture, bioreactors, biosensing, drug delivery, and engineering complex composite membranes

  6. Modification of optical surfaces employing CVD boron carbide coatings

    International Nuclear Information System (INIS)

    Non-reflective or high emissivity optical surfaces require materials with given roughness or surface characteristics wherein interaction with incident radiation results in the absorption and dissipation of a specific spectrum of radiation. Coatings have been used to alter optical properties, however, extreme service environments, such as experienced by satellite systems and other spacecraft, necessitate the use of materials with unique combinations of physical, chemical, and mechanical properties. Thus, ceramics such as boron carbide are leading candidates for these applications. Boron carbide was examined as a coating for optical baffle surfaces. Boron carbide coatings were deposited on graphite substrates from BCl3, CH4, and H2 gases employing chemical vapor deposition (CVD) techniques. Parameters including temperature, reactant gas compositions and flows, and pressure were explored. The structures of the coatings were characterized using electron microscopy and compositions were determined using x-ray diffraction. The optical properties of the boron carbide coatings were measured, and relationships between processing conditions, deposit morphology, and optical properties were determined

  7. Biomimetic surface modification of polyurethane with phospholipids grafted carbon nanotubes.

    Science.gov (United States)

    Tan, Dongsheng; Liu, Liuxu; Li, Zhen; Fu, Qiang

    2015-08-01

    To improve blood compatibility of polyurethane (PU), phospholipids grafted carbon nanotubes (CNTs) were prepared through zwitterion-mediated cycloaddition reaction and amide condensation, and then were added to the PU as fillers via solution mixing to form biomimetic surface. The properties of phospholipids grafted CNTs (CNT-PC) were investigated by thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance ((1) H NMR). The results indicated that the phospholipids were grafted onto CNTs in high efficiency, and the hydrophilicity and dispersibility of the modified CNTs were improved effectively. The structures and properties of composites containing CNT-PC were investigated by optical microscope, XPS, and water contact angles. The results indicated that phospholipids were enriched on the surface with addition of 0.1 wt % of CNT-PC, which significantly reduced protein adsorption and platelet adhesion. The method of carrying phospholipids on the nanofiller to modify polymers has provided a promising way of constructing biomimetic phospholipid membrane on the surface to improve blood compatibility. PMID:25630300

  8. SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANE BY TETHERING POLYPEPTIDES

    Institute of Scientific and Technical Information of China (English)

    Zhen-mei Liu; Zhi-kang Xu; Mathias Ulbricht

    2006-01-01

    Two kinds of polypeptides were tethered onto the surface of polypropylene microporous membrane (PPMM)through a ring opening polymerization of L-glutamate N-carboxyanhydride initiated by amino groups which were introduced by ammonia plasma and γ-aminopropyl triethanoxysilane treatments. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), scanning electron microscopy (SEM), together with water contact angle measurements were used to characterize the modified membranes. XPS analyses and FT-IR/ATR spectra demonstrated that polypeptides are actually grafted onto the membrane surface. The wettability of the membrane surface increases at first and then decreases with the increase in grafting degrees of polypeptide. Platelet adhesion and murine macrophage attachment experiments reveal an enhanced hemocompatibility for the polypeptide modified PPMMs. All these results give evidence that polypeptide grafting can simultaneously improve the hemocompatibility as well as reserve the hydrophobicity for the membrane, which will provide a potential approach to improve the performance of polypropylene hollow fiber microporous membrane used in artificial oxygenator.

  9. Surface modification of ultra-high molecular weight polyethylene for joint prosthesis and sports applications

    Institute of Scientific and Technical Information of China (English)

    H.Dong

    2004-01-01

    The recent progresses in the surfaee modification of ultra high molecular weight polyethylene (UHMWPE) using such advanced surface modification technologies as conventional ion implantation (CⅡ), new plasma immersion ion implantation (PⅢ) and novel active screen plasma (ASP), were all reported. Significantly improved wear resistance was achieved, which has great potential for extending the life-span of joint replacement prostheses and enhancing the performance of such sports equipment as skis and snowboards.

  10. Highly efficient industrial large-area black silicon solar cells achieved by surface nanostructured modification

    Science.gov (United States)

    Li, Ping; Wei, Yi; Zhao, Zengchao; Tan, Xin; Bian, Jiming; Wang, Yuxuan; Lu, Chunxi; Liu, Aimin

    2015-12-01

    Traditional black silicon solar cells show relatively low efficiencies due to the high surface recombination occurring at the front surfaces. In this paper, we present a surface modification process to suppress surface recombination and fabricate highly efficient industrial black silicon solar cells. The Ag-nanoparticle-assisted etching is applied to realize front surface nanostructures on silicon wafers in order to reduce the surface reflectance. Through a further tetramethylammonium hydroxide (TMAH) treatment, the carrier recombination at and near the surface is greatly suppressed, due to a lower surface dopant concentration after the surface modification. This modified surface presents a low reflectivity in a range of 350-1100 nm. Large-area solar cells with an average conversion efficiency of 19.03% are achieved by using the TMAH treatment of 30 s. This efficiency is 0.18% higher than that of standard silicon solar cells with pyramidal surfaces, and also a remarkable improvement compared with black silicon solar cells without TMAH modifications.

  11. 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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Nady, Norhan

    2016-01-01

    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. PMID:27096873

  14. Surface modification and column flotation of a massive ilmenite ore

    International Nuclear Information System (INIS)

    The main problems with ilmenite flotation in impeller-type flotation machines are the poor flotation behaviour of ilmenite and the negative effect of slimes. These cause high ilmenite losses in tailings even when a large dosage of fatty acid and fuel oil is consumed. In this study, microwave radiation pre-treatment and ilmenite surface activation were used to modify the surface properties of a massive ilmenite ore sample from Norway to improve ilmenite flotability. A column cell was used to minimize the negative effect of slimes on ilmenite separation efficiency. When ilmenite flotation was performed in a 1 litre Denver cell, the flotation recovery of titanium dioxide from the ilmenite ore sample was only 68.5% (31.1% TiO2) under conventional flotation conditions. After microwave radiation pre-treatment for three minutes at 2600 W and 2.45 GHz, the ferrous ions on ilmenite particle surfaces were converted into ferric ions; hence, the recovery increased from 68.5% to 86.8%. The concentrate grade increased from 31.1% TiO2 to 32.1% TiO2. In ilmenite activation flotation, Pb2+ ions can be selectively adsorbed on to ilmenite particle surfaces as active sites and therefore enhance the adsorption of oleate ions on ilmenite surfaces. With the addition of 60 g/ton Pb(NO3)2, ilmenite flotation recovery increased from 68.5% to 85.1%. However, the quality of ilmenite concentrates was not improved due to the negative effect of slimes. After a two stage cleaning, the grade of ilmenite concentrates was only about 31% TiO2. The combination of microwave radiation pre-treatment and the application of a column cell overcame both problems of poor flotability and the negative effect of slimes. When the Denver cell was replaced by a column cell and the massive ilmenite ore sample was pre-treated using microwave radiation for three minutes, the ilmenite concentrate grade increased from 31.1% TiO2 to 42.9% TiO2 and the titanium dioxide recovery increased from 68.5% to 90.7%. The ilmenite

  15. Plasma Surface Modification of Polyaramid Fibers for Protective Clothing

    Science.gov (United States)

    Widodo, Mohamad

    2011-12-01

    The purpose of this research was to develop a novel process that would achieve biocidal properties on Kevlar fabric via atmospheric pressure plasma jet (APPJ) induced-graft polymerization of monomers. In the course of the study, experiments were carried out to understand plasma-monomer-substrate interactions, particularly, how each of the main parameters in the plasma processing affects the formation of surface radicals and eventually the degree of graft polymerization of monomers. The study also served to explore the possibility of developing plasma-initiated and plasma-controlled graft polymerization for continuous operation. In this regards, three methods of processing were studied, which included two-step plasma graft-polymerization with immersion, two-step and one-step plasma graft-polymerization with pad-dry. In general, plasma treatment did not cause visible damage to the surface of Kevlar fibers, except for the appearance of tiny globules distributed almost uniformly indicating a minor effect of plasma treatment to the surface morphology of the polymer. From the examination of SEM images, however, it was found that a very localized surface etching seemed to have taken place, especially at high RF power (800 W) and long time of exposure (60 s), even in plasma downstream mode of operation. It was suggested that a small amount of charged particles might have escaped and reached the substrate surface. High density of surface radicals, which is the prerequisite for high graft density and high antimicrobial activity, was achieved by the combination of high RF power and short exposure time or low RF power and long time of exposure. This was a clear indication that the formation of surface radicals is a function of amount of the dissipated energy, which also explained the two-factor interaction between the two process parameters. XPS results showed that hydrolysis of the anilide bond of PPTA chains took place to some extent on the surface of Kevlar, leading to the

  16. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    International Nuclear Information System (INIS)

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N2 adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m2 g−1) and pore volume (0.016 cm3 g−1), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m2 g−1 and 0.701 cm3 g−1, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH2) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH2 bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds

  17. Ion beam modification of surfaces for biomedical applications

    International Nuclear Information System (INIS)

    Human life expectancy increased significantly within the last century. Hence, medical care must ever be improved. Optimizing artificial replacements such as hip joints or stents etc. is of special interest. For this purpose, new materials are constantly developed or known ones modified. This work focused on the possibility to change the chemistry and topography of biomedically relevant materials such as diamond-like carbon (DLC) and titanium dioxide (TiO2) by means of ion beam irradiation. Mass-separated ion beam deposition was used in order to synthesize DLC layers with a high sp3 content (> 70%), a sufficiently smooth surface (RMS<1 nm) and a manageable film thickness (50 nm). The chemistry of the DLC layers was changed by ion beam doping with different ion species (Ag,Ti) and concentrations. Additionally, the surface topography of silicon and titanium dioxide was altered by ion beam irradiation under non-perpendicular angle of incidence. The created periodic wave structures (so-called ripples) were characterized and their dependency on the ion energy was investigated. Moreover, ripples on silicon were covered with a thin DLC layer in order to create DLC ripples. The biocompatibility of all samples was investigated by adsorption experiments. For this purpose, human plasma fibrinogen (HPF) was used due to its ambiphilic character, which allows the protein to assume different conformations on materials with different hydrophilicities. Moreover, HPF is a crucial factor in the blood coagulation process. This work comes to the conclusion that the interaction of both, the surface chemistry and topography, has a strong influence on the adsorption behavior of HPF and thus the biocompatibility of a material. Both factors can be specifically tuned by means of ion beam irradiation.

  18. Surface modification of investment cast-316L implants: microstructure effects.

    Science.gov (United States)

    El-Hadad, Shimaa; Khalifa, Waleed; Nofal, Adel

    2015-03-01

    Artificial femur stem of 316L stainless steel was fabricated by investment casting using vacuum induction melting. Different surface treatments: mechanical polishing, thermal oxidation and immersion in alkaline solution were applied. Thicker hydroxyapatite (HAP) layer was formed in the furnace-oxidized samples as compared to the mechanically polished ones. The alkaline treatment enhanced the precipitation of HAP on the samples. It was also observed that the HAP precipitation responded differently to the different phases of the microstructure. The austenite phase was observed to have more homogeneous and smoother layer of HAP. In addition, the growth of HAP was sometimes favored on the austenite phase rather than on ferrite phase. PMID:25579929

  19. Surface modification of titanium alloys by intense pulsed electron beams

    International Nuclear Information System (INIS)

    The influence of intense pulsed electron beam (IPEB) treatment on the chemical composition and structure of titanium alloys surface layers is reviewed. The fatigue and oxidation behaviour of irradiated titanium alloys is analyzed. It is shown that IPEB processing allows one to improve service properties of titanium alloys dramatically. The recycling of some aircraft components after their 'long life' operation have to be realized using IPEB treatment at high values of the energy density in a pulse is also described. The application of IPEB processing is illustrated for compressor blades of aircraft engines

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

    DEFF Research Database (Denmark)

    Vutti, Surendra; Buch-Månson, Nina; Schoffelen, Sanne; Bovet, Nicolas Emile; Martinez, Karen Laurence; Meldal, Morten Peter

    2015-01-01

    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......-transfer reaction. Subsequently, D-amino acid adhesion peptides could be immobilized on the surface by use of Cu(I)-catalyzed click chemistry. This enabled the study of cell adhesion to the metal surface. In contrast to unmodified surfaces, the peptide-modified surfaces were able to maintain cell adhesion during...

  1. Surface modification of silicone rubber by ion implantation

    International Nuclear Information System (INIS)

    A study has been made on the wettability, structure, and chemical states of ion implanted silicone rubbers. C+, N2+, O2+, and Ar+ ion implantations were performed at energies of 50 and 100 keV at room temperature. The fluences ranged from 1012 to 1017 ions/cm2. Ion implantation caused the surface roughness to increase 2-3 times. Wettability was estimated by means of the sessile drop method using water, of which the results showed that the contact angle of water decreased from 98.90 to 480 as the fluence increased. The results of XPS measurements showed that implanted elements formed a Gaussian-like distribution, host elements were redistributed and no change in binding energies of O1s, C1s and Si2p occurred. Results of FT-IR-ATR showed that ion implantation broke up original chemical bonds to form new radicals, the amounts of which are related to the fluences. It is concluded that the change in wettability may be caused by formation of new radicals rather than roughening of the surface under ion implantation. (orig.)

  2. Modification of wool surface by liposomes for dyeing with weld.

    Science.gov (United States)

    Montazer, Majid; Zolfaghari, Alireza; Toliat, Taibeh; Moghadam, Mohammad Bameni

    2009-01-01

    In this research work, wool surface has been modified by liposome to investigate its effects on dyeing with weld, a yellow natural dye. To do this, samples were first treated with aluminium sulphate and afterward with different concentrations of liposomes at various temperatures for 30 minutes and, finally, dyed with weld at 75, 85, and 95 degrees C for 30, 45, and 60 minutes. K/S values of fabric samples were calculated and washing, light and rub fastness properties of the samples were indicated. The results proposed that the sample treated with 1% liposomes and dyed at 75 degrees C for 60 min has the highest K/S value. The central composite design (CCD) used for the experimental plan with three variables on the results of color strength and statistical analysis confirms the optimum conditions obtained by the experimental results. It was also found that washing, light, wet, and dry rub fastness properties of samples dyed with weld, including liposomes, have not significantly changed. The results of water drop absorption indicated that the hydrophobicity is higher for the samples pretreated with liposomes. The SEM picture of wool sample treated with mordant and liposomes and finally dyed with weld shows a coated layer on the fiber surface. PMID:19552578

  3. Surface modification of austenitic stainless steel by titanium ion implantation

    International Nuclear Information System (INIS)

    The wear properties of AISI 316 austenitic stainless steel implanted with Ti were investigated for ion doses in the range (2.3-5.4)x1016ionscm-2 and average ion energies of 60 and 90keV. The implanted layer was examined by Rutherford backscattering, from which the retained doses were determined, and glow discharge optical emission spectroscopy. Following implantation, the surface microhardness was observed to increase with the greatest change occurring at higher ion energy. Pin-on-disc wear tests and associated friction measurements were also performed under both dry and lubricated conditions using applied loads of 2N and 10N. In the absence of lubrication, breakthrough of the implanted layer occurred after a short sliding time; only for a dose of 5.1x1016ionscm-2 implanted at an average energy of 90keV was the onset of breakthrough appreciably delayed. In contrast, the results of tests with lubrication showed a more gradual variation, with the extent of wear decreasing with implant dose at both 2N and 10N loads. Finally, the influence of Ti implantation on possible wear mechanisms is discussed in the light of information provided by several surface characterization techniques. ((orig.))

  4. Modeling of metallic surface topography modification by high-frequency vibration

    Science.gov (United States)

    Yao, Zhehe; Mei, Deqing; Chen, Zichen

    2016-02-01

    High-frequency vibration is capable of modifying metallic surface topography significantly, while the underlying mechanisms are still unclear. In this study, the acoustic softening effect is considered to explain and model the effects of high-frequency normal vibration on surface topography. The surface asperities can be softened by the high-frequency vibration due to acoustic softening, leading to the enhancement of surface topography modification. A theoretical model for metallic surface topography modification by high-frequency vibration is proposed based on the acoustic plasticity. Numerical predictions of surface roughness evolution were conducted under various working conditions based on the model developed. It was found that the reduction of surface roughness (RSR) after vibration-assisted forming was affected by static stress, vibration amplitude, material properties and initial specimen surface roughness. The predictions using the developed model were compared with experimental data. Results showed that the predicted RSR agreed well with the experimental results, indicating that the analytical model is able to accurately capture surface topography evolution during vibration-assisted metal forming. This study provides a basis for understanding the underlying mechanisms of surface topography modification in vibration-assisted manufacturing.

  5. Quantitative DEMS study of ethanol oxidation: effect of surface structure and Sn surface modification.

    Science.gov (United States)

    Mostafa, Ehab; Abd-El-Latif, Abd-El-Aziz A; Ilsley, Richard; Attard, Gary; Baltruschat, Helmut

    2012-12-14

    Using the dual thin layer flow through cell, a semi-quantitative analysis of the volatile products during the electrooxidation of adsorbed and bulk solution of 0.01 M ethanol at polycrystalline platinum, smooth, roughened and Sn modified Pt(11,1,1), Pt(311) electrodes has been done by on-line differential electrochemical mass spectroscopy (DEMS). In addition to the current efficiency of CO(2), that of acetaldehyde was determined as a function of the flow rate. At polycrystalline platinum, ethanol oxidation produces only acetaldehyde; the amount of acetaldehyde further oxidized to acetic acid is negligible due to convection conditions. For comparison and for calibration purposes, i-propanol oxidation was examined for which acetone is the only oxidation product. At Pt(11,1,1), the main oxidation product is acetaldehyde. At Pt(311), in addition to acetaldehyde, acetic acid was also formed. Surface modification with Sn did not increase the reactivity of Pt(11,1,1) instead it led to inhibition of the ethanol oxidation. In the case of Pt(311), the onset potential of oxidation was shifted negatively by 0.2 V in the presence of Sn. The results of the potentiostatic measurements showed that this shift is not associated with the production of CO(2); rather acetic acid and acetaldehyde are the main oxidation products. PMID:23108295

  6. Study on the inorganic-organic surface modification of potassium titanate whisker

    Energy Technology Data Exchange (ETDEWEB)

    Yun Shan; Song Qianqian; Zhao Dongmei [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Qian Guimin, E-mail: guiminqian@gmail.com [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Li Xinning [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Li Wu [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China)

    2012-03-01

    ZnO coated potassium titanate whisker (PTW) was prepared via a facile chemical method, and coupling agent KH550 was used to modify the surface of ZnO coated PTW. Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectrophotometer and surface contact angle measurement were used to characterize the effect of surface modification. The results showed that the surface of PTW was uniformly coated by ZnO nanoparticles, and exhibited better ultraviolet absorption when the coating amount of ZnO was 5%. After modified by KH550, the modified ZnO/PTW showed better dispersion in ethanol solvent and the surface of modified ZnO/PTW became more hydrophobic-lipophilic than that of modified uncoated PTW. The method of inorganic-organic surface modification of PTW might be an effective way to greatly improve the compatibility of the whisker and the polymer matrix.

  7. SURFACE MODIFICATION AND DISPERSION OF NANODIAMOND IN CLEAN OIL

    Institute of Scientific and Technical Information of China (English)

    Yongwei Zhu; Xiangyang Xu; Baichun Wang; Zhijing Feng

    2004-01-01

    The effect of different kinds of surfactants on the size distribution of nanodiamond particles in clean oil was studied. Results show that the dispersing stability of nanodiamond modified with surfactants YS-1 and SB-18 simultaneously is much better than those modified with either of them because of synergism of the surfactants. And the particle size distribution in the system can be improved remarkably after the adoption of hyperdispersants such as SA-E and SA-F. Anchoring groups of those hyperdispersants can be bonded with the particle surface by chemical and/or hydrogen bonding and their soluble chains are well compatible with the dispersion media. As a result, the particles are uniformly distributed in the system owing to the steric stabilization. A very stable clean-oil based nanodiamond suspension with an average particle size of around 53.2 nm was prepared.

  8. Effects of different substrate surface modifications on the epitaxial ZnO/Si

    Science.gov (United States)

    Wang, Peng; Jin, Changlian; Zhan, Huahan; Chen, Xiaohang; Xu, Fuchun; Zhou, Yinghui; Wang, Huiqiong; Kang, Junyong

    2013-09-01

    To produce high quality ZnO/Si for the applications in short wavelength optoelectronic devices, the effects of different silicon surface modifications on the overgrown ZnO thin film were investigated. Samples were grown by a plasma assistant molecular beam epitaxy at room temperature, avoiding the oxidation of the Si surface and the thermal stress caused by difference of the thermal expansion coefficients between ZnO and silicon. Different modifications on the Si(100) substrate surface including nitridation, oxidation, and depositions of Mg and Zn, were employed. The effects on the overgrown ZnO layers and the interlayer SiOx were investigated by atomic force microscopy, photoluminescence, X-ray diffraction and auger depth electron spectroscopy. All the modifications were effective in different degrees at reducing the SiOx amorphous layer. However, different mechanisms resulted in distinct performance in crystal structure and optical property.

  9. Electrochemical surface modification technique to impede mild steel corrosion using perfluorooctanoic acid

    OpenAIRE

    Shubha H Natarj; Venkatesha T. Venkatarangaiah; ANANTHA N. SUBBA RAO

    2015-01-01

    The present work demonstrated that corrosion inhibition efficiency of electrochemically generated organic coat is remarkably more effective than self-assembled monolayer (SAM) generated by dip coating technique. Perfluorooctanoic acid (PFOA) is used to modify mild steel surface for effective protection. Infrared reflection absorption spectroscopy and contact angle measurements substantiate the modification of mild steel surface and its effect on surface hydrophobicity. A comparison between el...

  10. Realization of Dirac Cones in Few Bilayer Sb(111) Films by Surface Modification.

    Science.gov (United States)

    Pan, Hui; Wang, Xue-Sen

    2015-12-01

    We report the first-principle study on the recovery and linearization of Dirac cones in the electronic band structures of a few bilayer Sb(111) films (n-BL Sb) by surface modification. Due to the interaction between the surface states on the two surfaces of a free-standing film, the distorted Dirac cone in n-BL Sb(111) (n spintronic devices and their operation in complicated conditions. PMID:26293493

  11. Integration of plasma-assisted surface chemical modification, soft lithography, and protein surface activation for single-cell patterning

    Science.gov (United States)

    Cheng, Q.; Komvopoulos, K.

    2010-07-01

    Surface patterning for single-cell culture was accomplished by combining plasma-assisted surface chemical modification, soft lithography, and protein-induced surface activation. Hydrophilic patterns were produced on Parylene C films deposited on glass substrates by oxygen plasma treatment through the windows of polydimethylsiloxane shadow masks. After incubation first with Pluronic F108 solution and then serum medium overnight, surface seeding with mesenchymal stem cells in serum medium resulted in single-cell patterning. The present method provides a means of surface patterning with direct implications in single-cell culture.

  12. Spine interbody implants: material selection and modification, functionalization and bioactivation of surfaces to improve osseointegration.

    Science.gov (United States)

    Rao, Prashanth J; Pelletier, Matthew H; Walsh, William R; Mobbs, Ralph J

    2014-05-01

    The clinical outcome of lumbar spinal fusion is correlated with achievement of bony fusion. Improving interbody implant bone on-growth and in-growth may enhance fusion, limiting pseudoarthrosis, stress shielding, subsidence and implant failure. Polyetheretherketone (PEEK) and titanium (Ti) are commonly selected for interbody spacer construction. Although these materials have desirable biocompatibility and mechanical properties, they require further modification to support osseointegration. Reports of extensive research on this topic are available in biomaterial-centric published reports; however, there are few clinical studies concerning surface modification of interbody spinal implants. The current article focuses on surface modifications aimed at fostering osseointegration from a clinician's point of view. Surface modification of Ti by creating rougher surfaces, modifying its surface topography (macro and nano), physical and chemical treatment and creating a porous material with high interconnectivity can improve its osseointegrative potential and bioactivity. Coating the surface with osteoconductive materials like hydroxyapatite (HA) can improve osseointegration. Because PEEK spacers are relatively inert, creating a composite by adding Ti or osteoconductive materials like HA can improve osseointegration. In addition, PEEK may be coated with Ti, effectively bio-activating the coating. PMID:24890288

  13. Effect of surface modification on dielectric and magnetic properties of metal powder/polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, Kensaku, E-mail: ksonoda@ee.oulu.fi [Microelectronics and Materials Physics Laboratories, University of Oulu, P.O. Box 4500, FIN90014 Oulu (Finland); Electronic Materials Department, NOF Corporation, Yebisu Garden Place Tower, 20-3, Ebisu 4-chome, Shibuya-ku, Tokyo 150-6019 (Japan); Teirikangas, Merja; Juuti, Jari [Microelectronics and Materials Physics Laboratories, University of Oulu, P.O. Box 4500, FIN90014 Oulu (Finland); Moriya, Yasuo [Electronic Materials Department, NOF Corporation, Yebisu Garden Place Tower, 20-3, Ebisu 4-chome, Shibuya-ku, Tokyo 150-6019 (Japan); Jantunen, Heli [Microelectronics and Materials Physics Laboratories, University of Oulu, P.O. Box 4500, FIN90014 Oulu (Finland)

    2011-09-15

    Metal nanopowder (Co and Fe)/polymer composites, both with and without surface modification by behenic acid, were fabricated and their dielectric and magnetic properties were measured at 1 GHz to study the effect of surface modification on the electromagnetic properties. The relative permittivity and the real part of the permeability of the composites with surface modified powders were higher than those with unmodified powders. Related dielectric losses remained at almost the same level, but magnetic losses were somewhat increased. The increase of relative permittivity could result from the increased volume fraction of interphase with a slightly higher relative permittivity at the particle/polymer interface than that of the bulk polymer. The increase in the real part of the permeability may be caused by suppression of the induced demagnetizing field due to suppression of eddy currents by a better particle distribution and a decrease in effective agglomerate size because of the surface modification. - Highlights: > Metal/polymer composites from surface modified nano Co and Fe powders. > We evaluated their electromagnetic properties at 1 GHz. > The surface modification raised both {epsilon}' and {mu}'. > Especially, {epsilon}' of nano-Fe composite was raised from 5.5 to 14 at ca. 15 vol.%. > Particle dispersion, distribution and interphase play important roles in the effect.

  14. Effect of plasticizer on surface of free films prepared from aqueous solutions of salts of cationic polymers with different plasticizers

    Science.gov (United States)

    Bajdik, János; Fehér, Máté; Pintye-Hódi, Klára

    2007-06-01

    Acquisition of a more detailed understanding of all technological processes is currently a relevant tendency in pharmaceutical technology and hence in industry. A knowledge of film formation from dispersion of polymers is very important during the coating of solid dosage forms. This process and the structure of the film can be influenced by different additives. In the present study, taste-masking films were prepared from aqueous citric acid solutions of a cationic polymer (Eudragit ® E PO) with various hydrophilic plasticizers (glycerol, propylene glycol and different poly(ethylene glycols)). The mechanical properties, film thickness, wetting properties and surface free energy of the free films were studied. The aim was to evaluate the properties of surface of free films to predict the arrangement of macromolecules in films formed from aqueous solutions of salts of cationic polymers. A high molecular weight of the plasticizer decreased the work of deformation. The surface free energy and the polarity were highest for the film without plasticizer; the hydrophilic additives decreased these parameters. The direction of the change in polarity (a hydrophilic component caused a decrease in the polarity) was unexpected. It can be explained by the change in orientation of the macromolecules, a hydrophobic surface being formed. Examination of the mechanical properties and film thickness can furnish additional results towards a knowledge of film formation by this not frequently applied type of polymer from aqueous solution.

  15. Surface Modification of Block Copolymer Through Sulfur Containing Plasma Treatment.

    Science.gov (United States)

    Choi, Sang Wook; Shin, Jae Hee; Jeon, Min Hwan; Mun, Jeong Ho; Kim, Sang Ouk; Yeom, Geun Young; Kim, Kyong Nam

    2015-10-01

    Some of the important issues of block copolymer (BCP) as an application to the potential low cost next generation lithography are thermal stability and deformation during pattern transfer process in addition to defect density, line edge/width roughness, etc. In this study, sulfur containing plasma treatment was used to modify the BCP and the effects of the plasma on the properties of plasma treated BCP were investigated. The polystyrene hole pattern obtained from polystyrene polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) was initially degraded when the polystyrene hole was annealed at 190 °C for 15 min. However, when the hole pattern was treated using sulfur containing plasmas using H2S or SF6 up to 2 min, possibly due to the sulfurization of the polystyrene hole surface, no change in the hole pattern was observed after the annealing even though there is a slight change in hole shapes during the plasma treatment. The optimized plasma treated polystyrene pattern showed the superior characteristics as the mask layer by showing better thermal stability, higher chemical inertness, and higher etch selectivity during plasma etching. PMID:26726468

  16. Surface modification of silicone rubber by ion implantation

    International Nuclear Information System (INIS)

    A study has been made on the wettability, structure, and chemical states of ion implanted silicone rubber. C+-, N2+-, O2+, and Ar+ ion implantations were performed at energies of 50, 100, and 150 keV at room temperature. The doses ranged from 1 x 1012 to 1 x 1017 ions/cm2. Ion implantation caused the surface roughness to increase by 1∼5 times. Wettability was estimated by means of a sessile drop method using water. The contact angle of water immediately after ion-implantation decreased from 98.8deg to 48deg, as the dose increased. As the time elapsed, the contact angle gradually increased to approach the initial angle value. The results of XPS measurements showed that implanted elements formed a Gaussian-like distribution. The results of FT-IR-ATR showed that ion implantation broke original chemical bonds to form new radicals. The amounts of these radicals are related to the doses. Changes in wettability are mainly caused by formation of new radicals and their aging effects. (author)

  17. Surface Modification of Nickel Foams by a Slurry Aluminizing Process

    International Nuclear Information System (INIS)

    A novel slurry-based process for aluminizing nickel foams while improving the mechanical properties and conserving the excellent ductility is reported. Cellular unalloyed nickel foams with 92% porosity and uniform pore size and distribution were used as a starting material. Several slurries of different compositions were examined to investigate the possibility of developing an aluminide-nickel intermetallic coating on a Ni foam without considerably degrading the original ductile properties of the foam. The process temperature was varying from 400 to 850 deg. C and the process holding time was ranging between 2h to 6h. Scanning electron microscopy with an energy dispersive X-ray spectrometry and X-Ray diffraction were applied to assess the effectiveness of the aluminizing process and determine both the optimum parameters of the procedure (slurry composition, holding temperature and time) and the concentration profiles across the coating cross-section. The mechanical behavior of the aluminized Ni-foams was evaluated by the conduction of micro-tension tests. The resulting Ni-foams after aluminization retain the pore structure of original Ni-foams and present a thick outer surface layer which consists of a range of aluminide phases. The mechanical properties of the Ni-foams aluminized in low process temperature were insignificantly affected.

  18. Study on the mechanism of surface modification of magnesium oxysulfate whisker

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Li [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Nai, Xueying; Zhu, Donghai [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Jing, Yanwei [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Xin; Dong, Yaping [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Li, Wu, E-mail: driverlaoli@163.com [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China)

    2014-10-30

    Graphical abstract: - Highlights: • Physisorbed lauric acid was ruled out by FT-IR spectroscopy. • The inexistence of physisorbed magnesium laurate was proved by DSC analyses. • {sup 13}C NMR further verified the formation of COO–Mg< bonds on the surface of MOSw. • “Acid-base neutralization” was proved by the pH meter monitoring synchronously. • The type of surface modification of MOSw was proved to be chemical adsorption only. - Abstract: Hydrophobic-lipophilic magnesium oxysulfate whisker (MOSw) was prepared by surface modification with lauric acid and the surface morphology of MOSw was examined with field emission scanning electron microscope (FESEM). X-ray powder diffraction (XRD) was used to characterize the crystalline degree of MOSw and modified MOSw (MOSw-LA). Both FESEM and XRD suggested that modification occurred on the surface of MOSw exclusively. The inexistence of physisorbed lauric acid was proved by Fouier transform infrared (FT-IR) spectroscopy. Thermogravimetric analyses ruled out the possibility that magnesium laurate (LA-Mg) physisorbed on the surface of MOSw-LA. Solid state {sup 13}C nuclear magnetic resonance ({sup 13}C NMR) further verified the formation of COO–Mg< bonds based on the significant changes of chemical shift and decrease in intensity. Hence, we confirmed that the type of surface modification of MOSw with lauric acid was chemical adsorption taken place between lauric acid and Mg<. In order to study the dynamic state approach of this reaction, a pH meter was employed to monitor the reaction process synchronously, and then we proposed a reaction mechanism which was similar to the “acid-base neutralization”. This research provides a detailed explanation for a kind of surface modification, which may be further used in the performance of whisker/polymer matrix composites.

  19. Study on the mechanism of surface modification of magnesium oxysulfate whisker

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Physisorbed lauric acid was ruled out by FT-IR spectroscopy. • The inexistence of physisorbed magnesium laurate was proved by DSC analyses. • 13C NMR further verified the formation of COO–Mg< bonds on the surface of MOSw. • “Acid-base neutralization” was proved by the pH meter monitoring synchronously. • The type of surface modification of MOSw was proved to be chemical adsorption only. - Abstract: Hydrophobic-lipophilic magnesium oxysulfate whisker (MOSw) was prepared by surface modification with lauric acid and the surface morphology of MOSw was examined with field emission scanning electron microscope (FESEM). X-ray powder diffraction (XRD) was used to characterize the crystalline degree of MOSw and modified MOSw (MOSw-LA). Both FESEM and XRD suggested that modification occurred on the surface of MOSw exclusively. The inexistence of physisorbed lauric acid was proved by Fouier transform infrared (FT-IR) spectroscopy. Thermogravimetric analyses ruled out the possibility that magnesium laurate (LA-Mg) physisorbed on the surface of MOSw-LA. Solid state 13C nuclear magnetic resonance (13C NMR) further verified the formation of COO–Mg< bonds based on the significant changes of chemical shift and decrease in intensity. Hence, we confirmed that the type of surface modification of MOSw with lauric acid was chemical adsorption taken place between lauric acid and Mg<. In order to study the dynamic state approach of this reaction, a pH meter was employed to monitor the reaction process synchronously, and then we proposed a reaction mechanism which was similar to the “acid-base neutralization”. This research provides a detailed explanation for a kind of surface modification, which may be further used in the performance of whisker/polymer matrix composites

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

    DEFF Research Database (Denmark)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko; Kingshott, P.; Smets, Barth F.

    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...... 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...

  1. 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.

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

    International Nuclear Information System (INIS)

    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 H2SO4, KClO3 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.

  3. Surface modification technology on zirconium alloy for high temperature application

    International Nuclear Information System (INIS)

    After the Fukushima accident, it was recognized that a hydrogen related explosion is one of the major concerns of reactor safety during high temperature corrosion of zirconium alloys. It was reported that hydrogen is generated by a corrosion reaction of zirconium alloys, such as the fuel S36;, spacer grid, and channel box at a high temperature steam environment. Thus, the decrease of the high-temperature corrosion rate of zirconium alloys is an attractive solution to a nuclear power plant accident. Recently, the development concept of zirconium alloys has focused on a decrease of the corrosion rate under normal operation conditions to increase the operation economy and safety margin. However, it is unclear whether the corrosion resistance of zirconium alloys at normal operation in a 300 .deg. C water environment can be maintained at up to a high temperature steam condition of a 1200 .deg. C steam environment. In general, the corrosion rate of zirconium alloys is considerably increased with an increase in the environment temperature regardless of the alloy compositions. Thus, the improvement of the corrosion rate of zirconium based alloys at high temperature is a difficult problem using the commercial materials. To solve this problem, it is necessary to develop an advanced technology such as the coating of in corrodible materials on a zirconium surface. The coating technology is widely applied at the other industrial materials to reduce the corrosion damage, as the corrosion resistance can be easily obtained by a coating technology without a base material change. However, the optimized coating technology containing the materials and methods must be developed, since the chemical and mechanical failures of the coating layer are a serious concern in coating technology. Thus, this work studied the coating techniques to reduce the corrosion rate of a zirconium based alloy in a high-temperature steam environment

  4. An experimental study of USB flap noise reduction through mean flow modification. [Upper Surface Blown

    Science.gov (United States)

    Joshi, M. C.; Yu, J. C.

    1979-01-01

    The effect of mean flow modification on the noise production of upper surface blown flaps has been studied experimentally. Mean velocity profile at the nozzle exit was modified from the usual 'top-hat' shape to 'Gamma' and 'L'-shaped profiles. The 'L'-modification caused noise reduction around and above the peak frequency of the 'top-hat' spectrum when compared on an equal thrust per exit area basis. Modification to 'Gamma'-shaped profile resulted in a shift of the spectrum to lower frequencies and a lower overall noise reduction. These modifications alter the development of the large scale disturbances in the upper shear layer and trailing edge wake of the wall jet geometry.

  5. Acute in vivo toxicity mitigation of PEI-coated maghemite nanoparticles using controlled oxidation and surface modifications toward siRNA delivery.

    Science.gov (United States)

    Israel, Liron Limor; Lellouche, Emmanuel; Ostrovsky, Stella; Yarmiayev, Valeria; Bechor, Moshe; Michaeli, Shulamit; Lellouche, Jean-Paul Moshe

    2015-07-22

    A ceric ammonium nitrate (CAN)-based doping step was used for the fabrication of core maghemite nanoparticles (NPs) that enabled the obtainment of colloid particles with a view to a high-level nanoparticle (NP) surface doping by Ce(III/IV). Such doping of Ce(III/IV) cations enables one to exploit their quite rich coordination chemistry for ligand coordinative binding. In fact, they were shown to act as powerful Lewis acid centers for attaching any organic (Lewis base) ligand such as a 25 kDa branched PEI polymer. Resulting conPEI25-CAN-γ-Fe2O3 NPs have been fully characterized before a successful implementation of siRNA loading and cell delivery/gene silencing using a well-known dual luciferase system. This attractive result emphasized their significant potential as an NP platform technology toward additional MRI and/or drug delivery (peptide)-relating end applications. However, due to their high positive charge, PEI polymers can cause severe in vivo toxicity due to their interaction with negatively charged red blood cells (RBC), resulting in RBC aggregation and lysis, leading to thrombosis and, finally, to animal death. In order to mitigate these acute toxic effects, two different types of surface modifications were performed. One modification included the controlled oxidation of 0.1-5% of the PEI amines before or after conjugation to the NPs, using hydrogen peroxide or potassium persulfate. The other type of modification was the addition of a second biocompatible polyanionic polymer to the PEI grafted NPs, based on the concept of a layer-by-layer (LbL) technique. This modification is based on the coordination of another polyanionic polymer on the NPs surface in order to create a combined hybrid PEI and polyanionic polymer nanosystem. In both cases, the surface modification successfully mitigated the NP acute in vivo toxicity, without compromising the silencing efficiency. PMID:26120905

  6. Modification of surface properties of polyamide 6 films with atmospheric pressure plasma

    International Nuclear Information System (INIS)

    To investigate the effect of the different plasma gases treatment on the surface modification of atmospheric pressure plasma, polyamide 6 films were treated using pure helium (He), He/O2 and He/CF4, respectively. Atomic force microscopy (AFM) showed rougher surface, while X-ray photoelectron spectroscopy (XPS) revealed increased oxygen and fluorine contents after the plasma treatments. The plasma treated samples had lower water contact angles and higher T-peel strength than that of the control. The addition of small amount of O2 or CF4 to He plasma increases the effectiveness of the plasma treatment in polymer surface modification in terms of surface roughness, surface hydrophilic groups, etching rate, water contact angle and bonding strength.

  7. Modification of surface properties of polyamide 6 films with atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gao Zhiqiang, E-mail: sdgaozq@126.com [College of Textile and Clothing Engineering, Dezhou University, Shandong, 253023 (China)

    2011-05-01

    To investigate the effect of the different plasma gases treatment on the surface modification of atmospheric pressure plasma, polyamide 6 films were treated using pure helium (He), He/O{sub 2} and He/CF{sub 4}, respectively. Atomic force microscopy (AFM) showed rougher surface, while X-ray photoelectron spectroscopy (XPS) revealed increased oxygen and fluorine contents after the plasma treatments. The plasma treated samples had lower water contact angles and higher T-peel strength than that of the control. The addition of small amount of O{sub 2} or CF{sub 4} to He plasma increases the effectiveness of the plasma treatment in polymer surface modification in terms of surface roughness, surface hydrophilic groups, etching rate, water contact angle and bonding strength.

  8. Modification of surface properties of polyamide 6 films with atmospheric pressure plasma

    Science.gov (United States)

    Gao, Zhiqiang

    2011-05-01

    To investigate the effect of the different plasma gases treatment on the surface modification of atmospheric pressure plasma, polyamide 6 films were treated using pure helium (He), He/O 2 and He/CF 4, respectively. Atomic force microscopy (AFM) showed rougher surface, while X-ray photoelectron spectroscopy (XPS) revealed increased oxygen and fluorine contents after the plasma treatments. The plasma treated samples had lower water contact angles and higher T-peel strength than that of the control. The addition of small amount of O 2 or CF 4 to He plasma increases the effectiveness of the plasma treatment in polymer surface modification in terms of surface roughness, surface hydrophilic groups, etching rate, water contact angle and bonding strength.

  9. 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

    2015-08-01

    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. PMID:26023741

  10. 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. PMID:26253330

  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. Melanoma cell surface-expressed phosphatidylserine as a therapeutic target for cationic anticancer peptide, temporin-1CEa.

    Science.gov (United States)

    Wang, Che; Chen, Yin-Wang; Zhang, Liang; Gong, Xian-Ge; Zhou, Yang; Shang, De-Jing

    2016-07-01

    We have previously reported that temporin-1CEa, a cationic antimicrobial peptide, exerts preferential cytotoxicity toward cancer cells. However, the exact molecular mechanism for this cancer-selectivity is still largely unknown. Here, we found that the negatively charged phosphatidylserine (PS) expressed on cancer cell surface serves as a target for temporin-1CEa. Our results indicate that human A375 melanoma cells express 50-fold more PS than non-cancerous HaCaT cells. The expression of cell surface PS in various cancer cell lines closely correlated with their ability to be recognized, bound and killed by temporin-1CEa. Additionally, the cytotoxicity of temporin-1CEa against A375 cells can be ameliorated by annexin V, which binds to cell surface PS with high affinity. Moreover, the data of isothermal titration calorimetry assay further confirmed a direct binding of temporin-1CEa to PS, at a ratio of 1:5 (temporin-1CEa:PS). Interestingly, the circular dichroism spectra analysis using artificial biomembrane revealed that PS not only provides electrostatic attractive sites for temporin-1CEa but also confers the membrane-bound temporin-1CEa to form α-helical structure, therefore, enhances the affinity and membrane disrupting ability of temporin-1CEa. In summary, these findings suggested that the melanoma cells expressed PS may serve as a promising target for temporin-1CEa or other cationic anticancer peptides. PMID:26596643

  13. Diode laser surface modification of Ti6Al4V alloy to improve erosion wear resistance

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2008-07-01

    Full Text Available Purpose: Purpose of this paper : The purpose of the study was to develop new laser alloying technologyproviding high erosion wear resistance of the working surfaces of blades made of titanium alloy Ti6Al4V.Design/methodology/approach: High power diode laser HPDL with a rectangular laser beam spot ofmultimode and uniform intensity of laser radiation was applied in the process of laser surface modification of thetitanium alloy Ti6Al4V. During the laser surface remelting and alloying of the titanium alloy in argon and nitrogenatmospheres, surface layers of high hardness and significantly higher erosion wear resistant, compared with thebase material of titanium alloy Ti6Al4V, were produced.Findings: The surface layers are composites of titanium nitrides participations in the titanium alloy matrix.Hardness of the surface layers and erosion wear resistance depends strongly on parameters of laser processing andon the partial pressure of nitrogen in the gas mixture of nitrogen-argon atmosphere.Research limitations/implications: The most critical parameter of the functional quality of titanium alloyblades of turbofan engine and steam turbines is the fatigue strength, therefore further investigations are required todetermine the fatigue strength and also internal stresses in the nitrided surface layers.Practical implications: The novel technology of high power diode laser surface modification of the titaniumalloy Ti6Al4V can be applied to produce erosion wear resistant and long lifetime surface layers of turbofan engineblades and steam turbine blades.Originality/value: The laser surface modification of titanium alloy by the high power diode laser with therectangular laser beam spot of multimode and uniform intensity of laser radiation is very profitable in a case oflaser surface remelting and alloying because the treated surface is heated uniformly, so uniform penetration depthand uniform thickness of the surface layer can be achieved, as opposed from

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

    International Nuclear Information System (INIS)

    A microchip made of UV transparent polymer (CYTOP) that can perform selective cell culture has been fabricated by F2 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 F2 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.

  15. Investigation of phosphonic acid surface modifications on zinc oxide nanoparticles under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Quiñones, Rosalynn, E-mail: quinonesr@marshall.edu [Marshall University, Chemistry Department, 1 John Marshall Drive. Huntington, WV 25755 (United States); Rodriguez, Kate; Iuliucci, Robbie J. [Washington and Jefferson College, Chemistry Department, 60 South Lincoln St, Washington, PA 15301 (United States)

    2014-08-28

    Zinc oxide (ZnO) nanoparticles have emerged as a fascinating metal oxide semiconductor nanomaterial due largely to their wide array of properties that can be altered by surface modification. For example electrical and photonic properties include a range of conductivity from metallic to insulating (n-type and p- type conductivity), wide-band gap semiconductivity, room-temperature ferromagnetism, and chemical-sensing. Recently there has been much interest in the electronic and photonic properties of ZnO nanostructures as foreseeable applications include solar cells and laser diodes. For such purposes, controlling the surface functionalization is important and can be tailored by the chemical attachment of organic acids to the surface. The oxide surface readily reacts with organics forming self-assembled alkylphosphonate films. In this study, ZnO nanoparticles were modified using self-assembly thin films with phosphonic functional head groups. The amount of organic acid used in preparation of the thin film was shown to be important to the nanoparticle surface coverage. The modified ZnO nanoparticles were then characterized using infrared spectroscopy, powder X-ray diffraction, solid-state nuclear magnetic resonance, and scanning electron microscopy-energy dispersive X-ray spectroscopy. The interfacial bonding was identified by spectroscopy analysis to be the bidentate and tridentate motifs between the phosphonic head group and the oxide surface. Work function modification was measured using Ultraviolet photoelectron spectroscopy. The influences of temperature, humidity, and solvent rinse on the stability of the surface modifications were performed. - Highlights: • Zinc Oxide nanoparticles were modified using alkylphosphonic acid films. • Phosphonic acid modifications were strongly bonded and stable on the surface. • The surface coverage of the alkylphosphonic acid molecules was highly controlled. • The attachments were characterized using spectroscopy

  16. Investigation of phosphonic acid surface modifications on zinc oxide nanoparticles under ambient conditions

    International Nuclear Information System (INIS)

    Zinc oxide (ZnO) nanoparticles have emerged as a fascinating metal oxide semiconductor nanomaterial due largely to their wide array of properties that can be altered by surface modification. For example electrical and photonic properties include a range of conductivity from metallic to insulating (n-type and p- type conductivity), wide-band gap semiconductivity, room-temperature ferromagnetism, and chemical-sensing. Recently there has been much interest in the electronic and photonic properties of ZnO nanostructures as foreseeable applications include solar cells and laser diodes. For such purposes, controlling the surface functionalization is important and can be tailored by the chemical attachment of organic acids to the surface. The oxide surface readily reacts with organics forming self-assembled alkylphosphonate films. In this study, ZnO nanoparticles were modified using self-assembly thin films with phosphonic functional head groups. The amount of organic acid used in preparation of the thin film was shown to be important to the nanoparticle surface coverage. The modified ZnO nanoparticles were then characterized using infrared spectroscopy, powder X-ray diffraction, solid-state nuclear magnetic resonance, and scanning electron microscopy-energy dispersive X-ray spectroscopy. The interfacial bonding was identified by spectroscopy analysis to be the bidentate and tridentate motifs between the phosphonic head group and the oxide surface. Work function modification was measured using Ultraviolet photoelectron spectroscopy. The influences of temperature, humidity, and solvent rinse on the stability of the surface modifications were performed. - Highlights: • Zinc Oxide nanoparticles were modified using alkylphosphonic acid films. • Phosphonic acid modifications were strongly bonded and stable on the surface. • The surface coverage of the alkylphosphonic acid molecules was highly controlled. • The attachments were characterized using spectroscopy

  17. Synthesis and Surface Activity of Novel Triazole-based Cationic Gemini Surfactants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The synthesis and surfactant activities of two new cationic gemini surfactants containingtriazole compound as spacer were described. Their critical micelle concentrations (CMC), whichare 1.8 × l0-4 mol/L and 3.9× 10-4 mol/L respectively, are much lower than that of conventionalsurfactant cetyltrimethyl ammonium chloride (CTAC). In addition, compared with some geminisurfactants containing phenylene, xylylene and stilbenyl as spacer, this new kind of surfactants hasgood solubility in water at room temperature because of containing more hydrophilic groups oratoms in molecules.

  18. Deposition and Surface Modification of Low-k Thin Films For ILD Application In ULSI Circuits

    Directory of Open Access Journals (Sweden)

    Y.S. Mhaisagar

    2011-01-01

    Full Text Available The low-k thin films have been deposited successfully by sol gel technique using tetraethylorthosilicate (TEOS precursor and the surface of deposited thin films have been modified by wet chemical treatment using trimethylcholorsilane (TMCS and hexane solution with 15 % volume ratio to remove the hydroxyl groups from the surface of deposited low-k thin films. The characterization of the as deposited and surface modified low-k thin films has been carried out by Ellipsometer, Fourier transform infrared (FTIR spectrometer, and contact angle meter. For the determination of the dielectric constant of the deposited thin film the metal –insulator-semiconductor (MIS structure was formed by depositing the Aluminium (Al metal on the low-k thin film. Further the capacitance-voltage curve of the MIS structure has been obtained at 1 MHz frequency. The dielectric constant of the as deposited thin film is found to be 2.15. The lowering of O-H peaks and appearance of CH3 peaks in FTIR spectra confirms the surface modification of SiO2 films. The contact angle of the deposited thin film is changed from 83.3° to 104° after surface modification that validates the transformation of thin film surface from hydrophilic to hydrophobic after the surface modification treatment.

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

    International Nuclear Information System (INIS)

    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

  20. Synthesis of Perfluorinated Oxetane and Surface Properties of Its Cationic UV Cured Coating as a Reactive Additive

    Institute of Scientific and Technical Information of China (English)

    ZHAN Fu; ZHANG Yong; SHI Wen-fang

    2012-01-01

    Perfluorinated oxetane(F-OXE) was synthesized via the ring-opening reaction of epoxy-functionalized oxetane with 2-(perfluorooctyl)ethanol under base-catalysis,and characterized by FTIR and 1H NMR spectroscopy.The synthesized F-OXE was mixed with a commercial cationic UV curable resin,UVR6110,as a reactive additive at different mass fractions,and UV-irradiation cured in the presence of triphenylsulphonium hexafluoroantimonate as a cationic photoinitiator.The surface property study of cured films indicated that both hydrophobicity and oleophobicity were effectively enhanced by the addition of a small amount of F-OXE.The contact angles of water and 1-bromonaphthalene on the surface of the cured film with 1.0%(mass fraction) F-OXE loading increased from 72° to 106° and from 0° to 76°,respectively,compared with those on the surface of the film without F-OXE addition.The surface tension of UVR6110-F-OXE cured film decreased greatly from 55.6 mN/m of referenced film to 22.9 mN/m.The results from X-ray photoelectron spectroscopy analysis confirm the migration and aggregation effect of perfluoroalkyl group to the surface of cured film.For 1%(mass fraction) addition of F-OXE,the relative content of fluorine greatly increased from 0.70%(mass fraction) in the interior of the cured film to 36.73°%(mass fraction) at the surface of the cured film,whereas those of carbon and oxygen decreased from 73.29% to 40.96% and from 26.00% to22.30%,respectively.

  1. Surface modification of polysulfone films by UV-assisted treatments in the presence of reactive gases

    International Nuclear Information System (INIS)

    By UV-assisted surface modification of polysulfone thin films in the presence of a reactive gas atmosphere an efficient surface modification was obtained. Water Angle Contact (WCA) decreased up to 80 degree with the increase in the irradiation time. UV irradiation was carried out keeping a constant flow of oxygen or acrylic acid (AA) vapors during the photolysis at different times. FTIR-ATR and XPS spectra were obtained at the UFRGS and NEXAFS in the Laboratorio Nacional de Luz Sincrotron, Campinas. The data showed introduction of electronegative groups (OH, C=O e COO) at the polymer surface. The photolysis time has a direct relation with the WCA reduction. The concentration of electronegative groups introduced at the polymer surface correlated with the WCA data. The results also showed that irradiated films in the presence of AA vapors produced a photo-polymerization process forming a thin layer of polyacrylic acid film. (author)

  2. Biophysical bases of human plasma lipoprotein polydispersity: role of surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokh, Z.

    1984-11-01

    Metabolic depletion of the core of the triglyceride-rich lipoproteins via lipolysis results in the production of polydisperse species of particles within the density range of low density lipoproteins (LDL). Modifications of surface properties of plasma LDL may further contribute to LDL polydispersity. In this dissertation, we study the interactions with LDL of models of lipolysis-related surface products (i.e., phosphatidylcholine vesicles (PCV) and discoidal complexes (DC) of apoprotein AI and phosphatidylcholine) and examine the influence on such interactions of high density lipoproteins (HDL) and other relevant plasma components (lecithin:cholesterol acyltransferase (LCAT), lipid transfer proteins (LTPs), albumin, lysolecithin (LPC)). Based on the studies obtained in this dissertation LDL surface modification may contribute to LDL polydispersity. Since HDL is a major acceptor of PL, formation of surface-modified LDL (e.g., PL-enriched, larged LDL) in vivo would depend on LDL/HDL weight ratio in plasma. 140 references, 50 figures, 15 tables.

  3. Surface modifications of silica gel nanoparticles by silicic acid derivatives. Their structure and thermophysical properties

    International Nuclear Information System (INIS)

    The results of surface modifications of silica gel nanoparticles by silicic acid derivatives, including propyl-three-methoxy-silan (C6H16O3N), vinyl-three-(2-methoxy-ethoxy)-silan (C11H24Sl) and gamma-amino-propyl-three-methoxy-silan (C6H17O3N) were considered in this article. By means of inter esterification reaction with using silicic acid derivatives the surfaces of silica gel nanoparticles was modified. The structural changes of surface of silica gel nanoparticles after modification were evaluated by means of electron microscopy, XRD, infrared spectroscopy and differential thermal analysis methods. According to obtained results, the surface of modified samples became more hydrophobic, the water-absorbing capacity of silica gel nanoparticles decreased.

  4. Atmospheric Pressure Glow Discharge Plasma and Surface Modification of PET Textile by APGDP

    Science.gov (United States)

    Gu, Biao; Chen, Ru; Xu, Yin; Deng, Xiang; Shi, Qingjun

    2002-11-01

    Comparing with traditional chemistry method, surface modification of Polyethylene terephthalate (PET) fabrics by using of Atmospheric Pressure Glow Discharge Plasma (APGDP) has many advantages, such as low cost, low pollution and low energy consumption. So it has huge application in textile industry due to no requirement for vacuum system. In this paper, the generation and the characteristics of APGDP on a homemade device were investigated experimentally. The volt-ampere characteristic and the Lissajous figure demonstrated that, different from dielectric barrier discharge (DBD), there is no filaments appeared between electrodes. It is a glow discharge in one atmospheric pressure. Furthermore we investigated the surface modification of PET by APGDP. The relationship between PET characteristics (wettability, critical surface tension, timing-effect, dyeablity etc.) and various discharge parameters are discussed. At last, the measurements of ATR-FTIR (Attenuated Total Refraction-Fourier Transform Infarared Spectroscopy) and dyeing properties are demonstrated, and the mechanism of modification is analyzed basically. Key words: APGDP£¬Surface modification , PET

  5. The Synthesis, Surface Modification and Stability of SPIO Nanoparticles for MRI Application

    Czech Academy of Sciences Publication Activity Database

    Kovář, D.; Fohlerová, Z.; Malá, A.; Jiřík, Radovan; Starčuk jr., Zenon; Kalina, M.; Skládal, P.

    Ostrava : TANGER Ltd, 2013, s. 113. ISBN 978-80-87294-44-4. [NANOCON 2013. International Conference /5./. Brno (CZ), 16.10.2013-18.10.2013] R&D Projects: GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : nanoparticles * surface modifications Subject RIV: BH - Optics, Masers, Lasers

  6. Modification of surface properties of high and low density polyethylene by Ar plasma discharge

    Czech Academy of Sciences Publication Activity Database

    Švorčík, J.; Kolářová, K.; Slepička, P.; Macková, Anna; Novotná, M.; Hnatowicz, Vladimír

    2006-01-01

    Roč. 91, č. 6 (2006), s. 1219-1225. ISSN 0141-3910 R&D Projects: GA MŠk OC 527.100; GA MŠk 1P05OC014 Institutional research plan: CEZ:AV0Z10480505 Keywords : plasma polymerisation * surface modification Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.174, year: 2006

  7. PLASMA POLYMERIZATION OF HYDROPHILIC AND HYDROPHOBIC MONOMERS FOR SURFACE MODIFICATION OF NUCLE-MICROPOROUS MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    LI Xuefen; LI Zhifen; CHEN Chuanfu; WU Wenhui

    1990-01-01

    Surface modification of nucle-microporous membrane by plasma polymerization of HEMA, NVP and D4 has been studied. The hydrophilicity of membranes was increased with increasing of plasma polymerization time of hydrophilic monomers HEMA and NVP. The flow rate of water through the membrane was increased remarkably after plasma polymerization of HEMA on it.

  8. Remarkable fluorescence enhancement versus complex formation of cationic porphyrins on the surface of ZnO nanoparticles

    KAUST Repository

    Aly, Shawkat Mohammede

    2014-06-12

    Fluorescence enhancement of organic fluorophores shows tremendous potential to improve image contrast in fluorescence-based bioimaging. Here, we present an experimental study of the interaction of two cationic porphyrins, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride (TMPyP) and meso-tetrakis(4-N,N,N-trimethylanilinium)porphyrin chloride (TMAP), with cationic surfactant-stabilized zinc oxide nanoparticles (ZnO NPs) based on several steady-state and time-resolved techniques. We show the first experimental measurements demonstrating a clear transition from pronounced fluorescence enhancement to charge transfer (CT) complex formation by simply changing the nature and location of the positive charge of the meso substituent of the cationic porphyrins. For TMPyP, we observe a sixfold increase in the fluorescence intensity of TMPyP upon addition of ZnO NPs. Our experimental results indicate that the electrostatic binding of TMPyP with the surface of ZnO NPs increases the symmetry of the porphyrin macrocycle. This electronic communication hinders the rotational relaxation of the meso unit and/or decreases the intramolecular CT character between the cavity and the meso substituent of the porphyrin, resulting in the enhancement of the intensity of the fluorescence. For TMAP, on the other hand, the different type and nature of the positive charge resulting in the development of the CT band arise from the interaction with the surface of ZnO NPs. This observation is confirmed by the femtosecond transient absorption spectroscopy, which provides clear spectroscopic signatures of photoinduced electron transfer from TMAP to ZnO NPs. © 2014 American Chemical Society.

  9. Studies on cationic UV curing of cycloaliphatic diepoxide - epoxidised palm oil (EPO) for surface coatings

    International Nuclear Information System (INIS)

    In recent years, there are growing trends in using vegetables oil as raw materials in resin production. Development of new products from palm oil derivatives such as epoxidised palm oil (EPO) is of particular interest to this country. The compatibility of EPO with cycloaliphatic diepoxide allows the development of a wide range of radiation curable formulations by cationic photoinitiators. Curing was done by means of a 20 cm wide IST UV, machine with the conditions of 7.5A current and 4 m/min conveyor speed. Sulphonium and ferrocenium salts were used as the cationic photoinitiators. A study was formulated to compromise the investigation of various effects on the cured film properties. These effects include; types and concentration of photoinitiators, formulating ratios, reactive diluents, photosensitizers and postcuring conditions. The effects on the gel fraction, pendulum hardness, tensile strength and elongation at break were investigated. The results showed that 30% of EPO was the maximum value that can be used in the formulation. It was also found that triarylsulphonium hexafluorophosphate has a very low solubility in EPO

  10. Laser surface modification of tool steel for semi-solid steel forming

    OpenAIRE

    Brabazon, Dermot; Naher, Sumsun; Biggs, Patrick

    2008-01-01

    This paper presents an analysis of the effect of CO2 laser processing parameters on the surface modification and heat treatment of steels. The CO2 laser and sample movement process parameters are presented. The controlled operation of these in conjunction with each other is required to obtain better surface hardness and structure. H13 tool steel samples were rotated at high speeds to keep exposure times below 0.3s. Laser processed samples were analysed using EDX spectroscopy, optical microsco...

  11. Process mapping of laser surface modification of AISI 316L stainless steel for biomedical applications

    OpenAIRE

    Chikarakara, Evans; Naher, Sumsun; Brabazon, Dermot

    2010-01-01

    Due to limited lifetime for biomedical implants, material engineers have strived to improve the surface properties of existing biomaterials. Widely used methods of surface modification include film deposition such as physical vapour deposition (PVD), chemical vapour deposition (CVD) and diamond like carbon coating (DLC). Internal stresses make it difficult to bond such coatings to the substrates thus weakening the structure and limiting the life of implants. Laser glazing can achieve an amorp...

  12. STUDY ON THE SURFACE MODIFICATION OF NANOMETER CARBON PARTICLES IN ATMOSPHERIC PLASMA

    Institute of Scientific and Technical Information of China (English)

    Y.J. Ge; G.Q. Zhang; Y.M. Liu; X.G. Guo; Z.F. Zhao

    2002-01-01

    The surface modification of nanometer carbon material has been studied by usingan Induced Dielectric Barrier Discharge Plasma device (IDBD). The experimentalresults show that with different work gases and different discharge conditions, thesurface behaviors of carbon black can be changed according to needs, including theuse of different functional groups and the change of the surface roughness of carbonparticles etc., which increased the grinding and dispersion abilities in binder.

  13. High speed laser surface modification of Ti–6Al–4V

    OpenAIRE

    Chikarakara, Evans; Naher, Sumsun; Brabazon, Dermot

    2012-01-01

    Titanium and its alloys have been commonly used for biomedical implant applications for many years; however, associated high coefficient of friction, wear characteristics and low hardness have limited their long term performance. This article investigates the effects of the high speed laser surface modification of Ti6A1-4V on the microstructure, surface roughness, meltpool depth, phase transformation, residual strain, microhardness, and chemical composition. Laser treatment was carried out us...

  14. Polydopamine-Based Simple and Versatile Surface Modification of Polymeric Nano Drug Carriers

    OpenAIRE

    Park, Joonyoung; Brust, Tarsis F.; Lee, Hong Jae; Lee, Sang Cheon; Watts, Val J.; Yeo, Yoon

    2014-01-01

    The surface of a polymeric nanoparticle (NP) is often functionalized with cell-interactive ligands and/or additional polymeric layers to control NP interaction with cells and proteins. However, such modification is not always straightforward when the surface is not chemically reactive. For this reason, most NP functionalization processes employ reactive linkers or coupling agents or involve pre-functionalization of the polymer, which are complicated and inefficient. Moreover, pre-functionaliz...

  15. Surface Modification Process by Electrical Discharge Machining with Ti Powder Green Compact Electrode

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper describes a new method of surface modification by Electrical Discharge Machining (EDM). By using ordinary EDM machine tool and kerosene fluid, a hard ceramic layer can be created on the workpiece surface with Ti or other compressed powder electrode in a certain condition. This new revolutionary method is called Electrical Discharge Coating (EDC). The process of EDC begins with electrode wear during EDM,then a kind of hard carbide is created through the thermal and chemical reaction between the wo...

  16. Surface modification of porous poly(tetrafluoroethylene) film via cold plasma treatment

    Science.gov (United States)

    Shi, Tongna; Shao, Meiling; Zhang, Hongrui; Yang, Qing; Shen, Xinyuan

    2011-12-01

    In this study, cold plasma technology was applied for the surface modification of porous polytetrafluoroethylene (PTFE) film to improve the hydrophilicity. The surface properties of PTFE, modified by air, helium (He) or acrylic acid (AAc), were investigated with scanning electron microscopy (SEM), scanning probe microscope (SPM), in situ X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. The changes of the surface property before and after plasma treatment were discussed. According to SEM and SPM measurements, the surface roughness increased at different levels after plasma treatment. Compared to air and AAc plasma treatment, the He plasma treatment introduced large amounts of oxygen into the surface, as known from XPS results. Contact angle measurements revealed that the hydrophilicity of the PTFE film surface was greatly improved due to the surface roughness and changes of chemical elements on the PTFE surface.

  17. Surface Wettability Modification of Cyclic Olefin Polymer by Direct Femtosecond Laser Irradiation

    Directory of Open Access Journals (Sweden)

    Bing Wang

    2015-08-01

    Full Text Available The effect of laser irradiation on surface wettability of cyclic olefin polymer (COP was investigated. Under different laser parameters, a superhydrophilic or a superhydrophobic COP surface with a water contact angle (WCA of almost 0° or 163°, respectively, could be achieved by direct femtosecond laser irradiation. The laser power deposition rate (PDR was found to be a key factor on the wettability of the laser-treated COP surface. The surface roughness and surface chemistry of the laser-irradiated samples were characterized by surface profilometer and X-ray photoelectron spectroscopy, respectively; they were found to be responsible for the changes of the laser-induced surface wettability. The mechanisms involved in the laser surface wettability modification process were discussed.

  18. Surface modification of non-fabricated polypropylene textile in low-temperature plasma at atmospheric pressure

    International Nuclear Information System (INIS)

    The plasma activation of polypropylene (PP) non-fabricated textile in low temperature plasma at atmospheric pressure has been studied. The aim of the present work was the study of the surface modification of non-fabricated textiles in order to improve their hydrophilic properties. The surface treatment has been provided by nonequilibrium discharges as barrier discharge and surface discharge. The surface properties have been characterized by measuring the contact angle of PP textiles with liquid, standard industrial permeability measurements and absorption tests. The degradation of treated PP samples has also been studied. (author)

  19. 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)....

  20. Roughened titanium surfaces with silane and further RGD peptide modification in vitro

    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, ROC (China); Ko, Chia-Ling [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC (China)

    2013-07-01

    The strategy to achieve osteoregeneration of dental implants during early-stage regeneration is strongly related to surface conditions for achieving highly successful effects after implantation. Surface modifications, namely, mechanical ground, silanization, bonded and sandblasted with pentasequence Gly-Arg-Gly-Asp-Ser (GRGDS) peptide, and acid-etched with Arg-Gly-Asp (RGD) peptide, were compared for their ability to support cell attachment, proliferation, and differentiation on titanium surfaces. The characteristics and comparative in vitro bio-interactions toward osteoprogenitor cells were tested in the four groups with various surface modifications. Compared with the other groups, the sandblasted and acid-etched, and silane with subsequent RGD peptide modified surfaces had the smallest wetting angle, absence of a significant cell viability difference, and largest quantity of alkaline phosphatase production during the expressions of early-stage cell differentiation. The method of synthesizing GRGDS peptides on roughened titanium surfaces has the potential to provide a combination of early bone regeneration and implant of long-term anchored capabilities. Highlights: • The osteoregeneration during early-stage is strongly related to surface conditions. • The wettability with RGD peptide treated surfaces can be enhanced. • Rougher surface binding with RGD peptide can achieve better osseogeneration. • Surfaces with RGD peptide accelerate the progenitor bone cell mineralization.

  1. Preparation of superhydrophobic titanium surfaces via electrochemical etching and fluorosilane modification

    International Nuclear Information System (INIS)

    Highlights: ► We prepare superhydrophobic titanium surfaces via electrochemical etching and fluorosilane modification that have stability and abrasion resistance. ► Ion activities take place in neutral solution can drive Ti dissolution without affecting the pH. ► Analysis of the electrolyte, reaction process, and products indicates that the electrochemical processing is harmless and environment-friendly. - Abstract: The preparation of superhydrophobic surfaces on hydrophilic metal substrates depends on both surface microstructures and low surface energy modification. In this study, a simple and inexpensive electrochemical method for preparing robust superhydrophobic titanium surfaces is reported. The neutral sodium chloride solution is used as electrolyte. Fluoroalkylsilane (FAS) was used to reduce the surface energy of the electrochemically etched surface. Scanning electron microscopy (SEM) images, energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) spectra, and contact angle measurement are performed to characterize the morphological features, chemical composition, and wettability of the titanium surfaces. Stability and friction tests indicate that the prepared titanium surfaces are robust. The analysis of electrolyte, reaction process, and products demonstrates that the electrochemical processing is very inexpensive and environment-friendly. This method is believed to be easily adaptable for use in large-scale industry productions to promote the application of superhydrophobic titanium surfaces in aviation, aerospace, shipbuilding, and the military industry.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2008-03-01

    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).

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

    International Nuclear Information System (INIS)

    The Bombyx mori silk fibroin films (SFFs) were modified by a Cecropin B (CB) antimicrobial peptide, (NH2)-NGIVKAGPAIAVLGEAAL-CONH2, 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)

  5. 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)

  6. Effect of Hybrid Surface Modifications on Tensile Properties of Polyacrylonitrile- and Pitch-Based Carbon Fibers

    Science.gov (United States)

    Naito, Kimiyoshi

    2016-05-01

    Recent interest has emerged in techniques that modify the surfaces of carbon fibers, such as carbon nanotube (CNT) grafting or polymer coating. Hybridization of these surface modifications has the potential to generate highly tunable, high-performance materials. In this study, the mechanical properties of surface-modified polyacrylonitrile (PAN)-based and pitch-based carbon fibers were investigated. Single-filament tensile tests were performed for fibers modified by CNT grafting, dipped polyimide coating, high-temperature vapor deposition polymerized polyimide coating, grafting-dipping hybridization, and grafting-vapor deposition hybridization. The Weibull statistical distributions of the tensile strengths of the surface-modified PAN- and pitch-based carbon fibers were examined. All surface modifications, especially hybrid modifications, improved the tensile strengths and Weibull moduli of the carbon fibers. The results exhibited a linear relationship between the Weibull modulus and average tensile strength on a log-log scale for all surface-modified PAN- and pitch-based carbon fibers.

  7. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kai; Ma, Chun–Fang; Ling, Yuan; Li, Meng [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Gao, Qiang, E-mail: gaoqiang@cug.edu.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Luo, Wen–Jun, E-mail: heartnohome@yahoo.com.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2015-07-15

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N{sub 2} adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m{sup 2} g{sup −1}) and pore volume (0.016 cm{sup 3} g{sup −1}), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m{sup 2} g{sup −1} and 0.701 cm{sup 3} g{sup −1}, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH{sub 2}) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH{sub 2} bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds.

  8. Surface modification of tungsten carbide by electrical discharge coating (EDC) using a titanium powder suspension

    Energy Technology Data Exchange (ETDEWEB)

    Janmanee, Pichai, E-mail: pichai.j@rmutk.ac.th [Department of Industrial Engineering, Thammasat University, Klongluang, Pathumhtani (Thailand); Muttamara, Apiwat [Department of Industrial Engineering, Thammasat University, Klongluang, Pathumhtani (Thailand)

    2012-07-15

    Surface modification by a titanium coating layer onto a tungsten carbide surface by electrical discharge coating (EDC) was studied by considering a titanium coating modification as well as the completeness of the tungsten carbide surface. This was carried out by electrical discharge machining (EDM). The tungsten carbide material was produced using a fluid dielectric oil, which was mixed with titanium powder. The current and duty cycles were varied resulting in a change in the titanium coating layer thickness. Also, an analysis of the chemical composition using energy dispersive spectroscopy (EDS) revealed that a titanium coating layer was formed causing the hardness of the titanium surface to be close to that of tungsten carbide. The completeness of the surface was evaluated using scanning electron microscopy (SEM) and a small number of microcracks were found on the surface since the microcracks were filled and substituted by titanium powder and carbon (a hydrocarbon) that decomposed from the dielectric that acted as a combiner (TiC). Also, the high concentration of carbon increased the amount of Ti and C combination and TiC was formed, which enhanced the surface hardness of the coated layer to 1750 HV. The surface roughness of the coated layer decreased and this reduced the formation of microcracks on the surface workpiece.

  9. Surface modification of tungsten carbide by electrical discharge coating (EDC) using a titanium powder suspension

    International Nuclear Information System (INIS)

    Surface modification by a titanium coating layer onto a tungsten carbide surface by electrical discharge coating (EDC) was studied by considering a titanium coating modification as well as the completeness of the tungsten carbide surface. This was carried out by electrical discharge machining (EDM). The tungsten carbide material was produced using a fluid dielectric oil, which was mixed with titanium powder. The current and duty cycles were varied resulting in a change in the titanium coating layer thickness. Also, an analysis of the chemical composition using energy dispersive spectroscopy (EDS) revealed that a titanium coating layer was formed causing the hardness of the titanium surface to be close to that of tungsten carbide. The completeness of the surface was evaluated using scanning electron microscopy (SEM) and a small number of microcracks were found on the surface since the microcracks were filled and substituted by titanium powder and carbon (a hydrocarbon) that decomposed from the dielectric that acted as a combiner (TiC). Also, the high concentration of carbon increased the amount of Ti and C combination and TiC was formed, which enhanced the surface hardness of the coated layer to 1750 HV. The surface roughness of the coated layer decreased and this reduced the formation of microcracks on the surface workpiece.

  10. Surface modification of molten W exposed to high heat flux helium neutral beams

    International Nuclear Information System (INIS)

    High heat flux tests with central heat flux of 10.5 MW/m2 using helium neutral beams have been carried out on rolled tungsten. The energy of helium particles is 33 keV and the particle flux is 2 × 1021 m−2 s−1. An 80 × 65 × 3 mm3 rolled tungsten plate is firstly exposed to a 4.6 s pulse resulting in partially molten surfaces. Thereafter the tungsten plate is irradiated by several helium pulses with fluences of 1.2–2.5 × 1022/m2 and peak temperatures from 1450 to 2590 °C. The experiments show that: (1) helium-induced surface modification of the resolidified tungsten surface is very different from that of the non-molten surface; (2) the surface morphology of molten surface is closely related to the orientation of the resolidified grain; (3) the evolution of surface modifications, for both of the molten and non-molten tungsten surfaces, indicates a strong dependence on the surface temperature and local helium fluence

  11. LDPE Surface Modifications Induced by Atmospheric Plasma Torches with Linear and Showerhead Configurations

    CERN Document Server

    Rich, Sami Abou; Leroy, Perrine; Reniers, François; Nittler, Laurent; Pireaux, Jean-Jacques

    2016-01-01

    Low density polyethylene (LDPE) surfaces have been plasma modified to improve their nanostructural and wettability properties. These modifications can significantly improve the deposition of subsequent layers such as films with specific barrier properties. For this purpose, we compare the treatments induced by two atmospheric plasma torches with different configurations (showerhead vs. linear). The modifications of LDPE films in terms of chemical surface composition and surface morphology are evidenced by X-ray photoelectron spectro-scopy, water contact angles measurements, and atomic force microscopy. A comparison between the two post-discharge treatments is achieved for several torch-to-substrate distances (gaps), treatment times, and oxygen flow rates in terms of etching rate, roughening rate, diffusion of oxygen into the subsur-face and hydrophilicity. By correlating these results with the chemical composition of the post-discharges, we identify and compare the 'species which are responsible for the chemi...

  12. Surface modification of ferritic steels using MEVVA and duoplasmatron ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Kulevoy, Timur V., E-mail: kulevoy@itep.ru; Orlov, Nikolay N.; Rogozhkin, Sergey V.; Bogachev, Alexey A.; Nikitin, Alexander A.; Iskandarov, Nasib A.; Golubev, Alexander A. [State Scientific Center of the Russian Federation, Institute for Theoretical and Experimental Physics of National Research Centre “Kurchatov Institute,” Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Chalyhk, Boris B.; Fedin, Petr A.; Sitnikov, Alexey L.; Kozlov, Alexander V.; Kuibeda, Rostislav P.; Andrianov, Stanislav L. [State Scientific Center of the Russian Federation, Institute for Theoretical and Experimental Physics of National Research Centre “Kurchatov Institute,” Moscow (Russian Federation); Kravchuk, Konstantin S.; Useinov, Alexey S. [Technological Institute for Superhard and Novel Carbon Materials, Moscow (Russian Federation); Oks, Efim M. [Institute of High Current Electronics SB RAS, Tomsk (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk (Russian Federation)

    2016-02-15

    Metal Vapor Vacuum Arc (MEVVA) ion source (IS) is a unique tool for production of high intensity metal ion beam that can be used for material surface modification. From the other hand, the duoplasmatron ion source provides the high intensity gas ion beams. The MEVVA and duoplasmatron IS developed in Institute for Theoretical and Experimental Physics were used for the reactor steel surface modification experiments. Response of ferritic-martensitic steel specimens on titanium and nitrogen ions implantation and consequent vacuum annealing was investigated. Increase in microhardness of near surface region of irradiated specimens was observed. Local chemical analysis shows atom mixing and redistribution in the implanted layer followed with formation of ultrafine precipitates after annealing.

  13. 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.

  14. 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.

    2016-07-01

    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.

  15. Corrosion control and anti-hydrogen-absorption of fuel cladding by surface modification technology, Fresh Green

    International Nuclear Information System (INIS)

    We invent a surface modification technology, Fresh Green, to oxidize and carbonize a zirconium surface in the same process. XRD and XPS analyses indicated that a modified layer on zirconium surface is carbon-doped zirconium dioxide, in which some of oxygen atoms in monoclinic zirconium dioxide are replaced by carbon. The Fresh Green surface modification is applied for zircaloy-2 fuel cladding tubes at three different temperatures (500degC, 580degC and 660degC). Three autoclave experiments are conducted at three representative conditions: uniform corrosion, nodular corrosion, critical water corrosion. The Fresh Green surface modification at 500degC for 1h and 580degC for 1h reduce both corrosion rate and hydrogen-pickup to a half of that with untreated base material. This is because the Fresh Green layer is closely packed and adhered closely to the base material. Hydrides were found in the base material, through they were scarcely observed in the treated specimen at 500degC. Since the operating temperature of the Fresh Green process is lower than the final annealing temperature in a manufacturing process, the process does not affect the material property and crystal structure. The Fresh Green process, which can be operated at slightly higher pressure than ambient, can be introduced in the conventional manufacturing process without complicity. (author)

  16. Surface modification of multi-wall carbon nanotube with ultraviolet-curable hyperbranched polymer

    International Nuclear Information System (INIS)

    Surface modification is a general and efficient approach to improve the compatibility of carbon nanotube (CNT) with various matrixes. Here we report the modification of multi-wall carbon nanotube (MWCNT) with hyperbranched polymer which contains UV reactive functional groups. The modification promotes the incorporation of CNT into UV-curable resin, and when cured under UV irradiation to form a homogeneous film, the CNT will be chemically bonded with the matrix by crosslinking photopolymerization. For the unique mechanical properties of CNT, the mechanical properties of the cured MWCNT/UV-curable resin film were greatly improved compared with pure resin film as indicated by the increasing of Young's modulus, tensile strength, and toughness

  17. Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

    Science.gov (United States)

    Boyd, Darryl A.; Frantz, Jesse A.; Bayya, Shyam S.; Busse, Lynda E.; Kim, Woohong; Aggarwal, Ishwar; Poutous, Menelaos; Sanghera, Jasbinder S.

    2016-04-01

    In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

  18. Surface modification of multi-wall carbon nanotube with ultraviolet-curable hyperbranched polymer

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Wei; Xu Jianwen [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi Wenfang [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)], E-mail: wfshi@ustc.edu

    2008-04-30

    Surface modification is a general and efficient approach to improve the compatibility of carbon nanotube (CNT) with various matrixes. Here we report the modification of multi-wall carbon nanotube (MWCNT) with hyperbranched polymer which contains UV reactive functional groups. The modification promotes the incorporation of CNT into UV-curable resin, and when cured under UV irradiation to form a homogeneous film, the CNT will be chemically bonded with the matrix by crosslinking photopolymerization. For the unique mechanical properties of CNT, the mechanical properties of the cured MWCNT/UV-curable resin film were greatly improved compared with pure resin film as indicated by the increasing of Young's modulus, tensile strength, and toughness.

  19. Effect of antibody modifications on its biomolecular binding as determined by surface plasmon resonance.

    Science.gov (United States)

    Vashist, Sandeep Kumar

    2012-02-01

    A surface plasmon resonance (SPR)-based procedure was developed to determine the effect of antibody modifications on its biomolecular binding behavior. Mouse immunoglobulin G (IgG) was immobilized on a protein A-functionalized gold-coated SPR chip. Goat anti-mouse IgG and its various commercially available modifications (i.e., conjugated with atto 550, atto 647, tetramethylrhodamine isothiocyanate [TRITC], horseradish peroxidase [HRP], or biotin) were employed in exactly the same concentration for the detection of mouse IgG. The various modifications of goat anti-mouse IgG decreased its biomolecular binding to mouse IgG in the order of unmodified>HRP-labeled>atto 550-labeled>biotinylated>TRITC-labeled>atto 647-labeled. PMID:22093612

  20. 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.

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

    International Nuclear Information System (INIS)

    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.

  2. Modification of Photoluminescence Properties of ZnO Island Films by Localized Surface Plasmons

    Science.gov (United States)

    Zhang, Yang; Li, Xue-Hong; Peng, Cheng-Xiao

    2012-10-01

    The modification of localised surface plasmons of photoluminescence properties of ZnO is studied. It is found that the ultraviolet emission is drastically enhanced, and the visible emission related to the defects is almost completely suppressed, after an Au layer of nanoparticles is deposited on the surface of ZnO island films. This pronounced change in PL spectra is attributed to the efficient electron transfer via the coupling of localised surface plasmons at the interface between the Au nanoparticle layer and ZnO films.

  3. 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. PMID:23420113

  4. Electrochemical surface modification technique to impede mild steel corrosion using perfluorooctanoic acid

    Directory of Open Access Journals (Sweden)

    Shubha H Natarj

    2016-02-01

    Full Text Available The present work demonstrated that corrosion inhibition efficiency of electrochemically generated organic coat is remarkably effective than self-assembled monolayer (SAM generated by dip coating technique. Perfluorooctanoic Acid (PFOA is used to modify mild steel surface for effective protection. Infrared reflection absorption spectroscopy and contact angle measurements substantiate the modification of mild steel surface and its effect on surface hydrophobicity. A comparison between electrochemical properties of PFOA SAM generated by dip coat method (DC-PFOA and PFOA coat generated by electrochemical method (EC-PFOA is presented. Electrochemical measurements reveal that the corrosion protection efficiency of EC-PFOA (91% is much superior to DC-PFOA (28%.

  5. Diode laser surface modification of Ti6Al4V alloy to improve erosion wear resistance

    OpenAIRE

    A. Lisiecki; Klimpel, A

    2008-01-01

    Purpose: Purpose of this paper : The purpose of the study was to develop new laser alloying technologyproviding high erosion wear resistance of the working surfaces of blades made of titanium alloy Ti6Al4V.Design/methodology/approach: High power diode laser HPDL with a rectangular laser beam spot ofmultimode and uniform intensity of laser radiation was applied in the process of laser surface modification of thetitanium alloy Ti6Al4V. During the laser surface remelting and alloying of the tita...

  6. Surface and bulk modification of W-La2O3 armor mock-up

    International Nuclear Information System (INIS)

    W-(1%)La2O3 has been investigated after thermal exposure in the Quasi-Stationary Plasma Accelerator facility in order to obtain information regarding its surface damage and morphological modification. The profilometry measurements and the Scanning Electron Microscopy analysis showed that surface erosion and corrugation become more pronounced with increasing the thermal load. The La2O3 particle density inside the sample has been measured by Scanning Auger Microscopy. It decreases with increasing the thermal load and presents a negative gradient from the bulk to the surface.

  7. Ion-Beam Surface Modification of Strut Dowel Used in ITER PF Support

    Science.gov (United States)

    Luo, Rongrong; Li, Pengyuan; Han, Shilei; Sun, Zhenchao; Pan, Chuanjie; Shen, Liru; Jin, Fanya

    2013-03-01

    In this paper, surface modification of the strut dowel used in ITER PF support is reported. Different ions (nitrogen/titanium) with different doses are implanted into the surface of strut dowel. The result of Auger Electron Spectroscopy (AES) indicates that nitrogen can be implanted more deeply than titanium under the implantation condition of 60 kV accelerating voltage and a dose of 8 × 1017/cm2 nitrogen. Surface Micro Hardness (SMH) and wear resistance are improved remarkably. Further SEM observation shows that there are no obvious scratches and damages after wear test.

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

    Science.gov (United States)

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

    2015-09-01

    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.

  9. Growth and surface modification of LaFeO3 thin films induced by reductive annealing

    International Nuclear Information System (INIS)

    Highlights: • LaFeO3 was grown by molecular beam epitaxy on ZrO2:Y2O3. • The film was highly oriented but not single crystalline. • Angle resolved XPS revealed differences between surface and bulk oxygen. • Annealing the film in vacuum resulted in the sequential reduction of Fe cations. • A greater degree of Fe reduction was found at the surface. - Abstract: The mixed electronic and ionic conductivity of perovskite oxides has enabled their use in diverse applications such as automotive exhaust catalysts, solid oxide fuel cell cathodes, and visible light photocatalysts. The redox chemistry at the surface of perovskite oxides is largely dependent on the oxidation state of the metal cations as well as the oxide surface stoichiometry. In this study, LaFeO3 (LFO) thin films grown on yttria-stabilized zirconia (YSZ) was characterized using both bulk and surface sensitive techniques. A combination of in situ reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) demonstrated that the film is primarily textured in the [1 0 0] direction and is stoichiometric. High-resolution transmission electron microscopy measurements show regions that are dominated by [1 0 0] oriented LFO grains that are oriented with respect to the substrates lattice. However, selected regions of the film show multiple domains of grains that are not [1 0 0] oriented. The film was annealed in an ultra-high vacuum chamber to simulate reducing conditions and studied by angle-resolved X-ray photoelectron spectroscopy (XPS). Iron was found to exist as Fe(0), Fe(II), and Fe(III) depending on the annealing conditions and the depth within the film. A decrease in the concentration of surface oxygen species was correlated with iron reduction. These results should help guide and enhance the design of LFO materials for catalytic applications

  10. Actinide cation-cation complexes

    International Nuclear Information System (INIS)

    The +5 oxidation state of U, Np, Pu, and Am is a linear dioxo cation (AnO2+) with a formal charge of +1. These cations form complexes with a variety of other cations, including actinide cations. Other oxidation states of actinides do not form these cation-cation complexes with any cation other than AnO2+; therefore, cation-cation complexes indicate something unique about AnO2+ cations compared to actinide cations in general. The first cation-cation complex, NpO2+·UO22+, was reported by Sullivan, Hindman, and Zielen in 1961. Of the four actinides that form AnO2+ species, the cation-cation complexes of NpO2+ have been studied most extensively while the other actinides have not. The only PuO2+ cation-cation complexes that have been studied are with Fe3+ and Cr3+ and neither one has had its equilibrium constant measured. Actinides have small molar absorptivities and cation-cation complexes have small equilibrium constants; therefore, to overcome these obstacles a sensitive technique is required. Spectroscopic techniques are used most often to study cation-cation complexes. Laser-Induced Photacoustic Spectroscopy equilibrium constants for the complexes NpO2+·UO22+, NpO2+·Th4+, PuO2+·UO22+, and PuO2+·Th4+ at an ionic strength of 6 M using LIPAS are 2.4 ± 0.2, 1.8 ± 0.9, 2.2 ± 1.5, and ∼0.8 M-1

  11. Effects of Surface-modification of Carbon Black on the Characteristics of Polymerized Toner

    International Nuclear Information System (INIS)

    Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surface-modified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner

  12. Enhanced modification of tungsten surface by nanostructure formation during high flux deuterium plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.Y. [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, Sichuan 621907 (China); Luo, G.N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Schut, H. [Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Yuan, Y.; Fu, B.Q.; Godfrey, A. [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Temmerman, G.De. [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Trilateral Euregio Cluster, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands)

    2014-04-01

    The morphology changes induced by low energy deuterium ions on tungsten surfaces is studied for particle fluxes similar to those expected in the ITER divertor, as high as 10{sup 24} m{sup −2} s{sup −1}. A new type of surface modifications by formation of nanostructures is observed to occur under those conditions. The nanostructures formation is critically dependent on the particle flux and ion energy, and affected by surface temperature and particle fluence. It correlates with the formation of nano-cavities at a depth of about 40 nm below the surface. In addition, the positron annihilation Doppler broadening (PADB) measurements reveal a significant increase of defect concentration (mostly vacancy-type) after plasma exposure, and the evolution of defects is in line with the surface morphology changes with fluence and surface temperature. The possible mechanism of cyclic trap mutation and dislocation loop punching due to high flux D exposure is discussed.

  13. Enhanced modification of tungsten surface by nanostructure formation during high flux deuterium plasma exposure

    Science.gov (United States)

    Xu, H. Y.; Luo, G. N.; Schut, H.; Yuan, Y.; Fu, B. Q.; Godfrey, A.; Liu, W.; Temmerman, G. De.

    2014-04-01

    The morphology changes induced by low energy deuterium ions on tungsten surfaces is studied for particle fluxes similar to those expected in the ITER divertor, as high as 1024 m-2 s-1. A new type of surface modifications by formation of nanostructures is observed to occur under those conditions. The nanostructures formation is critically dependent on the particle flux and ion energy, and affected by surface temperature and particle fluence. It correlates with the formation of nano-cavities at a depth of about 40 nm below the surface. In addition, the positron annihilation Doppler broadening (PADB) measurements reveal a significant increase of defect concentration (mostly vacancy-type) after plasma exposure, and the evolution of defects is in line with the surface morphology changes with fluence and surface temperature. The possible mechanism of cyclic trap mutation and dislocation loop punching due to high flux D exposure is discussed.

  14. Effects of Surface-modification of Carbon Black on the Characteristics of Polymerized Toner

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ho; Kim, Dae Su [Chungbuk National University, Cheongju (Korea, Republic of)

    2013-10-15

    Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surface-modified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner.

  15. Surface modification of a POSS-nanocomposite material to enhance cellular integration of a synthetic bioscaffold.

    Science.gov (United States)

    Crowley, Claire; Klanrit, Poramate; Butler, Colin R; Varanou, Aikaterini; Platé, Manuela; Hynds, Robert E; Chambers, Rachel C; Seifalian, Alexander M; Birchall, Martin A; Janes, Sam M

    2016-03-01

    Polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) is a versatile nanocomposite biomaterial with growing applications as a bioscaffold for tissue engineering. Integration of synthetic implants with host tissue can be problematic but could be improved by topographical modifications. We describe optimization of POSS-PCU by dispersion of porogens (sodium bicarbonate (NaHCO3), sodium chloride (NaCl) and sucrose) onto the material surface, with the principle aim of increasing surface porosity, thus providing additional opportunities for improved cellular and vascular ingrowth. We assess the effect of the porogens on the material's mechanical strength, surface chemistry, wettability and cytocompatibilty. Surface porosity was characterized by scanning electron microscopy (SEM). There was no alteration in surface chemistry and wettability and only modest changes in mechanical properties were detected. The size of porogens correlated well with the porosity of the construct produced and larger porogens improved interconnectivity of spaces within constructs. Using primary human bronchial epithelial cells (HBECs) we demonstrate moderate in vitro cytocompatibility for all surface modifications; however, larger pores resulted in cellular aggregation. These cells were able to differentiate on POSS-PCU scaffolds. Implantation of the scaffold in vivo demonstrated that larger pore sizes favor cellular integration and vascular ingrowth. These experiments demonstrate that surface modification with large porogens can improve POSS-PCU nanocomposite scaffold integration and suggest the need to strike a balance between the non-porous surfaces required for epithelial coverage and the porous structure required for integration and vascularization of synthetic scaffolds in future construct design. PMID:26790147

  16. Surface modification of a POSS-nanocomposite material to enhance cellular integration of a synthetic bioscaffold

    Science.gov (United States)

    Crowley, Claire; Klanrit, Poramate; Butler, Colin R.; Varanou, Aikaterini; Platé, Manuela; Hynds, Robert E.; Chambers, Rachel C.; Seifalian, Alexander M.; Birchall, Martin A.; Janes, Sam M.

    2016-01-01

    Polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) is a versatile nanocomposite biomaterial with growing applications as a bioscaffold for tissue engineering. Integration of synthetic implants with host tissue can be problematic but could be improved by topographical modifications. We describe optimization of POSS-PCU by dispersion of porogens (sodium bicarbonate (NaHCO3), sodium chloride (NaCl) and sucrose) onto the material surface, with the principle aim of increasing surface porosity, thus providing additional opportunities for improved cellular and vascular ingrowth. We assess the effect of the porogens on the material's mechanical strength, surface chemistry, wettability and cytocompatibilty. Surface porosity was characterized by scanning electron microscopy (SEM). There was no alteration in surface chemistry and wettability and only modest changes in mechanical properties were detected. The size of porogens correlated well with the porosity of the construct produced and larger porogens improved interconnectivity of spaces within constructs. Using primary human bronchial epithelial cells (HBECs) we demonstrate moderate in vitro cytocompatibility for all surface modifications; however, larger pores resulted in cellular aggregation. These cells were able to differentiate on POSS-PCU scaffolds. Implantation of the scaffold in vivo demonstrated that larger pore sizes favor cellular integration and vascular ingrowth. These experiments demonstrate that surface modification with large porogens can improve POSS-PCU nanocomposite scaffold integration and suggest the need to strike a balance between the non-porous surfaces required for epithelial coverage and the porous structure required for integration and vascularization of synthetic scaffolds in future construct design. PMID:26790147

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

    International Nuclear Information System (INIS)

    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, NH2+ 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gomathi, N., E-mail: gomathi@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Department of Space, Trivandrum, 695547 (India); Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, 721302 (India); Rajasekar, R. [Materials Science Center, Indian Institute of Technology, Kharagpur, 721302 (India); Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk, 561-756 (Korea, Republic of); Babu, R. Rajesh [Rubber Technology Center, Indian Institute of Technology, Kharagpur, 721302 (India); Advanced Tyre Research, Apollo Tyres, Baroda, 391750 (India); Mishra, Debasish [Department of Biotechnolgy, Indian Institute of Technology, Kharagpur, 721302 (India); Neogi, S. [Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, 721302 (India)

    2012-10-01

    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{sup 2+} and NH{sup +} was observed. Reduced platelet adhesion and increased partial thromboplastin time evidenced the increased blood compatibility. - Highlights: Black-Right-Pointing-Pointer Improved biocompatibility and blood compatibility of polypropylene. Black-Right-Pointing-Pointer Nitrogen plasma surface modification. Black-Right-Pointing-Pointer Maintaining a balance between polar group incorporation and weight loss due to etching. Black-Right-Pointing-Pointer Optimization of process conditions by response surface methodology.

  19. Surface Modification of Biodegradable Polymers towards Better Biocompatibility and Lower Thrombogenicity.

    Directory of Open Access Journals (Sweden)

    Andreas Rudolph

    Full Text Available Drug-eluting stents (DES based on permanent polymeric coating matrices have been introduced to overcome the in stent restenosis associated with bare metal stents (BMS. A further step was the development of DES with biodegradable polymeric coatings to address the risk of thrombosis associated with first-generation DES. In this study we evaluate the biocompatibility of biodegradable polymer materials for their potential use as coating matrices for DES or as materials for fully bioabsorbable vascular stents.Five different polymers, poly(L-lactide PLLA, poly(D,L-lactide PDLLA, poly(L-lactide-co-glycolide P(LLA-co-GA, poly(D,L-lactide-co-glycolide P(DLLA-co-GA and poly(L-lactide-co-ε-caprolactone, P(LLA-co-CL were examined in vitro without and with surface modification. The surface modification of polymers was performed by means of wet-chemical (NaOH and ethylenediamine (EDA and plasma-chemical (O2 and NH3 processes. The biocompatibility studies were performed on three different cell types: immortalized mouse fibroblasts (cell line L929, human coronary artery endothelial cells (HCAEC and human umbilical vein endothelial cells (HUVEC. The biocompatibility was examined quantitatively using in vitro cytotoxicity assay. Cells were investigated immunocytochemically for expression of specific markers, and morphology was visualized using confocal laser scanning (CLSM and scanning electron (SEM microscopy. Additionally, polymer surfaces were examined for their thrombogenicity using an established hemocompatibility test.Both endothelial cell types exhibited poor viability and adhesion on all five unmodified polymer surfaces. The biocompatibility of the polymers could be influenced positively by surface modifications. In particular, a reproducible effect was observed for NH3-plasma treatment, which enhanced the cell viability, adhesion and morphology on all five polymeric surfaces.Surface modification of polymers can provide a useful approach to enhance their

  20. Electrochemical behavior of SUS316L stainless steel after surface modification

    Institute of Scientific and Technical Information of China (English)

    梁成浩; 郭亮; 陈婉; 刘敬肖

    2003-01-01

    The surface modification for SUS316L stainless steel was carried out by electroplating Rh, ion beam assisted deposition Ta2O5 and sol-gel-derived TiO2. In Tyrodes stimulated body fluid, the surface modified samples were investigated with electrochemical techniques. The results indicate that the electrochemical stability and dissolution are improved significantly after surface modification. Moreover, as to ion beam assisted deposition Ta2O5 and sol-gel-derived TiO2 film, the metals d orbit electron holes filled up by the oxygen electrons make against the adsorption of hydrogen. Thus the cathode process, which is controlled by the hydrogen reduction, is held back. X-ray diffraction analysis of SUS316L stainless steel after surface modification reveal that each method forms the uniform and compact film on SUS316L stainless steel. These films prevent the dissolving of elements and improve passivation property of the SUS316L stainless steel.

  1. Surface modification of battery electrodes via electroless deposition with improved performance for Na-ion batteries.

    Science.gov (United States)

    Lahiri, Abhishek; Olschewski, Mark; Gustus, René; Borisenko, Natalia; Endres, Frank

    2016-06-01

    Sodium-ion batteries (SIBs) are emerging as potential stationary energy storage devices due to the abundance and low cost of sodium. A simple and energy efficient strategy to develop electrodes for SIBs with a high charge/discharge rate is highly desirable. Here we demonstrate that by surface modification of Ge, using electroless deposition in SbCl3/ionic liquids, the stability and performance of the anode can be improved. This is due to the formation of GexSb1-x at the surface leading to better diffusion of Na, and the formation of a stable twin organic and inorganic SEI which protects the electrode. By judicious control of the surface modification, an improvement in the capacity to between 50% and 300% has been achieved at high current densities (0.83-8.4 A g(-1)) in an ionic liquid electrolyte NaFSI-[Py1,4]FSI. The results clearly demonstrate that an electroless deposition based surface modification strategy in ionic liquids offers exciting opportunities in developing superior energy storage devices. PMID:27189079

  2. Surface modification to produce hydrophobic nano-silica particles using sodium dodecyl sulfate as a modifier

    Science.gov (United States)

    Qiao, Bing; Liang, Yong; Wang, Ting-Jie; Jiang, Yanping

    2016-02-01

    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-2, which is near the highest value in the literature. The optimal parameters of the SDS/SiO2 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 TiO2 particles, which indicated that the protons of the Brønsted acid sites on the surface of SiO2 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 new modification route.

  3. Formation of superpower volume discharges and their application for modification of surface of metals

    Science.gov (United States)

    Tarasenko, Victor F.; Shulepov, M. A.

    2008-05-01

    The results of experimental investigations of a volume avalanche discharge initiated by an e-beam (VADIEB) and surface layer of Cu and AlBe foils modifications at the plasma action of VADIEB are given. The volume discharge in the air of atmosphere pressure formed in the gap with the cathode having small curvature radius and with high voltage pulses of nanosecond duration and positive and negative polarity. A supershort avalanche electron beam (SAEB) with formation conditions in gases under atmospheric pressure have been investigated. It is proved that the surface layer is cleared of carbon at foil treatment, and atoms of oxygen penetrate into a foil. It is show that the cleaning depth depends on polarity of voltage pulses. At positive polarity of a copper foil electrode the cleaning is observed at the depth over 50 nm, and atoms of oxygen penetrate at the depth up to 25 nm. Plasma of the superpower volume discharge of nanosecond duration with a specific excitation power of hundreds of MW/cm3, and SAEB, and the discharge plasma radiation of various spectral ranges (including UV, VUV and X-ray) has the influence on the anode. The supershort avalanche electronic beam is generated only at negative polarity of a voltage pulse on an electrode with a small radius of curvature. SAEB influence on modifications of the copper foil surface is registered. VADIEB is easily realized in various gases and at various pressures, and, at gas pressure decrease the density of the beam current in helium can achieve 2 kA/cm2. It allows predicting an opportunity of VADIEB application for metal surface modifications in various technological processes, and for surface dielectric modifications at the certain design of the anode.

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

    International Nuclear Information System (INIS)

    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.

  5. 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.

  6. 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.

  7. Nitrogen ion implantation on stainless steel: AFM study of surface modification

    International Nuclear Information System (INIS)

    This work presents a study by means of atomic force microscopy (AFM) of the modification of the surface topography of AISI 304 austenitic stainless steel after N-ion implantation, irradiated by 1 x 1015 N2+/cm2 at 80 keV. Prior to the implantation surface modification, the samples were electropolished for the optimum observation of the surface at a small scale to obtain an initial surface with the smaller roughness. The electrolytic bath was composed of a mixture of water/sulphuric acid/orthophosphoric acid in percentages 20, 20 and 60%, respectively. Once the surface was optimized, the samples were implanted and observed by AFM, a new technique whose importance relies on its resolution power, allowing the acquisition of topographic images of the surface with nanometric resolution. Thanks to the high resolution power could be observed that ion implantation increases the surface roughness and promotes the apparition of 3 μm wide and 10 nm depth craters as well as the apparition of products with singular morphology

  8. In vitro bioactivity investigations of Ti-15Mo alloy after electrochemical surface modification.

    Science.gov (United States)

    Kazek-Kęsik, Alicja; Kuna, Karolina; Dec, Weronika; Widziołek, Magdalena; Tylko, Grzegorz; Osyczka, Anna M; Simka, Wojciech

    2016-07-01

    Titanium and its aluminum and vanadium-free alloys have especially great potential for medical applications. Electrochemical surface modification improves their surface bioactivity and stimulates osseointegration process. In this work, the effect of plasma electrolytic oxidation of the β-type alloy Ti-15Mo surface on its bioactivity is presented. Bioactivity of the modified alloy was investigated by immersion in simulated body fluid (SBF). Biocompatibility of the modified alloys were tested using human bone marrow stromal cells (hBMSC) and wild intestinal strains (DV/A, DV/B, DV/I/1) of Desulfovibrio desulfuricans bacteria. The particles of apatite were formed on the anodized samples. Human BMSC cells adhered well on all the examined surfaces and expressed ALP, collagen, and produced mineralized matrix as determined after 10 and 21 days of culture. When the samples were inoculated with D. desulfuricans bacteria, only single bacteria were visible on selected samples. There were no obvious changes in surface morphology among samples. Colonization and bacterial biofilm formation was observed on as-ground sample. In conclusion, the surface modification improved the Ti-15Mo alloy bioactivity and biocompatibility and protected surface against colonization of the bacteria. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 903-913, 2016. PMID:25952109

  9. Covalent modification of carbon surfaces with cyclodextrins by mediated oxidation of β-cyclodextrin monoanions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • >Covalent grafting of carbon surfaces by mediated oxidation of cyclodextrin monoanions > The use of ferrocene as redox catalyst to prepare electrochemically modified electrodes. • EPR spectrum of electrochemically generated cyclodextrin radicals. • Electrochemical polymerization of cyclodextrine over glassy carbon surfaces. • Formation of inclusion complexes between ferrocene and β-cyclodextrin in dimethylsulfoxide. - Abstract: The covalent grafting of glassy carbon and highly oriented pyrolytic graphite with cyclodextrins is reported in this work. The modification procedure is based in the concept that oxidation of organic anions generates radicals which react with carbon surfaces. These radical species are generated through a redox catalysis mechanism involving the formation of ferrocenium ion, which in turn oxidizes the cyclodextrin monoanion to afford an oxygen-centered free radical that ultimately reacts either in solution or with the surface, affording a strong attachment of cyclodextrin molecules to the carbon surface. The intervention of this radical was established from spectroelectrochemical EPR experiments. Atomic force microscopy imaging showed that the attached organic layer is thick while cyclic voltammetry experiments confirmed that this modified surface behaves as an ultramicroelectrode array. This kind of modification allows incorporate cyclodextrin to an electrode surface without a binder, making the modified electrode useful to be tested in forthcoming sensor studies

  10. Synthesis, surface properties and oil solubilisation capacity of cationic gemini surfactants

    NARCIS (Netherlands)

    Dam, Th.; Engberts, J.B.F.N.; Karthäuser, J.; Karaborni, S.; Os, N.M. van

    1996-01-01

    The critical micelle concentration (CMC) and the surface tension at the CMC have been determined for the gemini surfactants alkanediyl-u,w-bis(dimethyla1kylammoniubmr omide) by means of dynamic surface tension measurements. For the same number of carbon atoms in the hydrophobic chain per hydrophilic

  11. Modeling of methylene blue cation adsorption on the surface of carbon nanotubes

    International Nuclear Information System (INIS)

    Molecular dynamics modeling of the process of MB+ adsorption at the CNT surface in aqueous medium has demonstrated formation of stable CNT:(MB+)n positively charged complexes. It is proposed that the hydrophilicity and positive charge at the surface of such nanohybrides is the reason for prevention of their aggregation and precipitation in water dispersions

  12. Removal of oil droplets from water using carbonized rice husk: enhancement by surface modification using polyethylenimine.

    Science.gov (United States)

    Lin, Kun-Yi Andrew; Yang, Hongta; Petit, Camille; Chen, Shen-Yi

    2015-06-01

    Carbonized rice husk (CRH) is a promising material to separate oil from water owing to its abundance, low-cost, and environmentally benign characteristics. However, CRH's performance is somewhat limited by its similar surface charge to that of oil, leading to repulsive interactions. To improve the separation efficiency of CRH, CRH was modified via impregnation with a cationic biocompatible polymer, polyethlyenimine (PEI) to form PEI-CRH. The modified sample exhibits a remarkably higher (10-50 times) oil/water (O/W) separation efficiency than that of the unmodified one. Small PEI-CRH particles (about 64 μm) are found to adsorb oil droplets faster and larger quantities than bigger particles (about 113 and 288 μm). PEI-CRH exhibits higher separation efficiency at high temperatures owing to the destabilization of the emulsion. It is also found that the oil adsorption mechanism involves a chemical interaction between PEI-CRH and oil droplets. The addition of NaCl considerably improves the separation efficiency, while the addition of a cationic surfactant has the opposite effect. In acidic emulsions, PEI-CRH adsorbs more oil than in neutral or basic conditions owing to favorable attractive forces between oil droplets and the surface of PEI-CRH. PEI-CRH can be easily regenerated by washing with ethanol. These promising features of PEI-CRH indicate that PEI-CRH could be an efficient and low-cost adsorbent for the O/W separation applications. PMID:25529491

  13. Surface Modification of Carbon Nanotubes with Conjugated Polyelectrolytes: Fundamental Interactions and Applications in Composite Materials, Nanofibers, Electronics, and Photovoltaics

    KAUST Repository

    Ezzeddine, Alaa

    2015-10-01

    Ever since their discovery, Carbon nanotubes (CNTs) have been renowned to be potential candidates for a variety of applications. Nevertheless, the difficulties accompanied with their dispersion and poor solubility in various solvents have hindered CNTs potential applications. As a result, studies have been developed to address the dispersion problem. The solution is in modifying the surfaces of the nanotubes covalently or non-covalently with a desired dispersant. Various materials have been employed for this purpose out of which polymers are the most common. Non-covalent functionalization of CNTs via polymer wrapping represents an attractive method to obtain a stable and homogenous CNTs dispersion. This method is able to change the surface properties of the nanotubes without destroying their intrinsic structure and preserving their properties. This thesis explores and studies the surface modification and solublization of pristine single and multiwalled carbon nanotubes via a simple solution mixing technique through non-covalent interactions of CNTs with various anionic and cationic conjugated polyelectrolytes (CPEs). The work includes studying the interaction of various poly(phenylene ethynylene) electrolytes with MWCNTs and an imidazolium functionalized poly(3-hexylthiophene) with SWCNTs. Our work here focuses on the noncovalent modifications of carbon nanotubes using novel CPEs in order to use these resulting CPE/CNT complexes in various applications. Upon modifying the CNTs with the CPEs, the resulting CPE/CNT complex has been proven to be easily dispersed in various organic and aqueous solution with excellent homogeneity and stability for several months. This complex was then used as a nanofiller and was dispersed in another polymer matrix (poly(methyl methacrylate), PMMA). The PMMA/CPE/CNT composite materials were cast or electrospun depending on their desired application. The presence of the CPE modified CNTs in the polymer matrix has been proven to enhance

  14. 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...

  15. Protein Adsorption to Surface Chemistry and Crystal Structure Modification of Titanium Surfaces

    Directory of Open Access Journals (Sweden)

    Ryo Jimbo

    2010-07-01

    Full Text Available Objectives: To observe the early adsorption of extracellular matrix and blood plasma proteins to magnesium-incorporated titanium oxide surfaces, which has shown superior bone response in animal models.Material and Methods: Commercially pure titanium discs were blasted with titanium dioxide (TiO2 particles (control, and for the test group, TiO2 blasted discs were further processed with a micro-arc oxidation method (test. Surface morphology was investigated by scanning electron microscopy, surface topography by optic interferometry, characterization by X-ray photoelectron spectroscopy (XPS, and by X-ray diffraction (XRD analysis. The adsorption of 3 different proteins (fibronectin, albumin, and collagen type I was investigated by an immunoblotting technique.Results: The test surface showed a porous structure, whereas the control surface showed a typical TiO2 blasted structure. XPS data revealed magnesium-incorporation to the anodic oxide film of the surface. There was no difference in surface roughness between the control and test surfaces. For the protein adsorption test, the amount of albumin was significantly higher on the control surface whereas the amount of fibronectin was significantly higher on the test surface. Although there was no significant difference, the test surface had a tendency to adsorb more collagen type I.Conclusions: The magnesium-incorporated anodized surface showed significantly higher fibronectin adsorption and lower albumin adsorption than the blasted surface. These results may be one of the reasons for the excellent bone response previously observed in animal studies.

  16. High-productivity membrane adsorbers: Polymer surface-modification studies for ion-exchange and affinity bioseparations

    Science.gov (United States)

    Chenette, Heather C. S.

    This dissertation centers on the surface-modification of macroporous membranes to make them selective adsorbers for different proteins, and the analysis of the performance of these membranes relative to existing technology. The common approach used in these studies, which is using membrane technology for chromatographic applications and using atom transfer radical polymerization (ATRP) as a surface modification technique, will be introduced and supported by a brief review in Chapter 1. The specific approaches to address the unique challenges and motivations of each study system are given in the introduction sections of the respective dissertation chapters. Chapter 2 describes my work to develop cation-exchange membranes. I discuss the polymer growth kinetics and characterization of the membrane surface. I also present an analysis of productivity, which measures the mass of protein that can bind to the stationary phase per volume of stationary phase adsorbing material per time. Surprisingly and despite its importance, this performance measure was not described in previous literature. Because of the significantly shorter residence time necessary for binding to occur, the productivity of these cation-exchange membrane adsorbers (300 mg/mL/min) is nearly two orders of magnitude higher than the productivity of a commercial resin product (4 mg/mL/min). My work studying membrane adsorbers for affinity separations was built on the productivity potential of this approach, as articulated in the conclusion of Chapter 2. Chapter 3 focuses on the chemical formulation work to incorporate glycoligands into the backbone of polymer tentacles grown from the surface of the same membrane stationary phase. Emphasis is given to characterizing and testing the working formulation for ligand incorporation, and details about how I arrived at this formulation are given in Appendix B. The plant protein, or lectin, Concanavalin A (conA) was used as the target protein. The carbohydrate affinity

  17. Surface modification of a POSS-nanocomposite material to enhance cellular integration of a synthetic bioscaffold

    OpenAIRE

    Crowley, C.; Klanrit, P; C.R. Butler; Varanou, A; Platé, M.; Hynds, R. E.; Chambers, R. C.; Seifalian, A. M.; Birchall, M A; Janes, S M

    2016-01-01

    Polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) is a versatile nanocomposite biomaterial with growing applications as a bioscaffold for tissue engineering. Integration of synthetic implants with host tissue can be problematic but could be improved by topographical modifications. We describe optimization of POSS-PCU by dispersion of porogens (sodium bicarbonate (NaHCO3), sodium chloride (NaCl) and sucrose) onto the material surface, with the principle aim of incre...

  18. Surface Modification of Cellulose by Covalent Grafting and Physical Adsorption for Biocomposite Applications

    OpenAIRE

    Bruce, Carl

    2014-01-01

    There is an increasing interest to replace fossil-based materials with renewable alternatives. Cellulose fibers/nanofibrils (CNF) are sustainable options since they are biobased and biodegradable. In addition, they combine low weight with high strength; making them suitable to, for example, reinforce composites. However, to be able to use them as such, modifications are often necessary. This study therefore aimed at modifying cellulose fibers, model surfaces of cellulose and CNF. Cellulose fi...

  19. Click chemistry modification of surface-bound peptides towards applications in printable electronics

    OpenAIRE

    Schlageter, Martin

    2015-01-01

    This thesis shows the development of a method for the modification of surface-bound peptides. Initial attempts to functionalize amino acids with ferrocene derivatives led to a post-synthetic click grafting strategy, which could be shown to be feasible. This approach was extended to a two-step consecutive click sequence. Additionally, the grafting of Coordination clusters with the described method was investigated.

  20. A comprehensive review of nanostructured materials by ultrasonic nanocrystal surface modification technique

    OpenAIRE

    Auezhan Amanov; Young-Sik Pyun

    2015-01-01

    Nanostructured materials (NMs) possess outstanding properties than conventional coarse-grained (CG) materials. Hence designing potentially cost-efficient and environmentally products made of NMs with better are on high demand. This paper gives a comprehensive review of the most recent progress in production, characterisation and fundamental understanding of NMs produced by ultrasonic nanocrystal surface modification (UNSM) technique. In this review, we demonstrate a detailed description of th...

  1. Microwave-Assisted Surface Modification of Metallocene Polyethylene for Improving Blood Compatibility

    OpenAIRE

    Hemanth Mohandas; Gunalan Sivakumar; Palaniappan Kasi; Saravana Kumar Jaganathan; Eko Supriyanto

    2013-01-01

    A wide number of polymers are being used for various medical applications. In this work, microwave-assisted surface modification of metallocene polyethylene (mPE) was studied. FTIR analysis showed no significant changes in the chemical groups after treatment. Contact angle analysis revealed a decrease in contact angle of the treated samples insinuating increasing hydrophilicity and better biocompatibility. Qualitative analysis of treated samples using scanning electron microscope (SEM) depict...

  2. Surface modification of polymers for biocompatibility via exposure to extreme ultraviolet radiation

    OpenAIRE

    Ahad, I.U.; Bartnik, A.; Fiedorowicz, Henryk; Kostecki, Jerzy; Korkzyc, Barbara; Ciach, Tomasz; Brabazon, Dermot

    2013-01-01

    Polymeric biomaterials are being widely used for the treatment of various traumata, diseases and defects in human beings due to ease in their synthesis. As biomaterials have direct interaction with the extracellular environment in the biological world, biocompatibility is a topic of great significance. The introduction or enhancement of biocompatibility in certain polymers is still a challenge to overcome. Polymer biocompatibility can be controlled by surface modification. Various physical an...

  3. Tailoring of thermomechanical properties of thermoplastic nanocomposites by surface modification of nanoscale silica particles

    OpenAIRE

    Becker, Carsten; Krug, Herbert; Schmidt, Helmut K.

    1996-01-01

    Thermoplastic nanocomposites based on linear polymethacrylates as matrix materials and spherical silica particles as fillers have been synthesized using the in situ free radical polymerization technqiue of methacrylate monomers in presence of specially functionalized SiO2 nanoparticulate fillers. Uncoated monodisperse silica particles with particle sizes 100 nm and 10 nm were used as reference fillers. For surface modification, the alcoholic dispersions of the fillers were treated with approp...

  4. Surface modification and characterization of carbon black; UV cured colored epoxy composites

    OpenAIRE

    Atif, Muhammad

    2014-01-01

    Carbon Black is inexpensive widely used industrial filler, but its dispersability in solvents/polymeric media has always been a critical point. As a result either surfactants or higher mechanical forces have been utilized to disperse it well in the media. First part of research was aimed at surface modification of CB to increase its dispersability in different solvents and epoxy that directly effects filler-medium interactions. Type and magnitude of this interaction differs with structure and...

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

    Energy Technology Data Exchange (ETDEWEB)

    Jennifer Anne Harnisch

    2002-06-27

    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.

  6. 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. PMID:21683520

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

    International Nuclear Information System (INIS)

    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 AlO2 or TiO2, 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:YVO4 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, Ti6O, Ti3O 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

  8. High intensity pulsed plasma beams modification of surface morphology and mechanical properties of steels

    International Nuclear Information System (INIS)

    Surface engineering technology is well-known method used to obtain, investigate and apply surface layers with different improved properties, than the base material. High energy ion or plasma pulse is one of contemporary intensively investigated methods used for surface modification. Achieved up to now results show, that steel irradiation with high-intensive pulsed beam can change surface morphology and the mechanical properties of material. The aim of this work was to investigate the correlation of carbon concentration and type of ion used on those changes. Intense pulsed nitrogen and argon plasma beam were used for modification of constructional, unalloyed steels. The duration of pulse was in the range of microseconds, density of energy was about 6 J/cm2. Each sample was irradiated with 5 impulses. Heating and cooling processes were on non-equilibrium type. The surface morphology was analysed using scanning electron microscopy. Measurements of surface roughness, hardness HV5 and wear resistance (the pin-on-disc method) were carried out. Obtained results are presented in this work. (author)

  9. Modification of a metallic surface in a vacuum arc discharge plasma using thermally stimulated ion diffusion

    Science.gov (United States)

    Muboyadzhyan, S. A.

    2008-12-01

    A new process for modifying a metallic surface in a vacuum arc discharge plasma using thermally stimulated ion diffusion is considered. The effect of the bias voltage (negative substrate potential) on the processes that occur on the surface of a treated part is studied when the substrate material interacts with an accelerated metallic-ion flow. The phase and elemental compositions of the modified layer are studied for substrates made of nickel-based superalloys, austenitic and martensitic steels, and titanium-based alloys. The heat resistance, the salt corrosion resistance, and the corrosion cracking resistance of steels and titanium-based alloys are investigated after their modification in vacuum arc plasmas of pure metals (Ti, Zr, Al, Cr, Y) and related alloys. The surface modification caused by the thermally stimulated ion saturation of the surfaces of parts made from structural materials is shown to change the structural-phase states of their surfaces and, correspondingly, the properties of these materials in relation to the state of the surface.

  10. CF4 radio frequency plasma surface modification of silicone rubber for use as outdoor insulations

    International Nuclear Information System (INIS)

    For further prolonging the serve life of silicone rubber (SIR) for outdoor insulation and increasing its resistance of pollution flashover, surface modifications of SIR were carried out via CF4 capacitively coupled plasma at radio frequency (RF) power of 60, 100 and 200 W for a treatment time up to 20 min under CF4 flow rate of 20 sccm. Static contact angle measurement was employed to estimate the change of hydrophobicity of the modified SIR. The variation of the surface functional groups of the modified SIR was observed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrum and X-ray photoelectron spectroscopy (XPS). The surface topography was observed by atom force microscopy (AFM). The results indicate that the static contact angle of SIR surface is improved from 100.7 deg. to 150.2 deg. via the CF4 plasma modification, and the super-hydrophobic surface of modified SIR, which corresponds to a static contact angle of 150.2 deg., appears at RF power of 200 W for a 5-min treatment time. According to the results, it is suggested that the formation of super-hydrophobic surface is ascribed to the co-action of the increase of roughness created by the ablation reaction of CF4 plasma and the formation of [-SiFx(CH3)2-x-O-]n (x = 1, 2) structure produced by the direct attachment of F atoms to Si

  11. Surface modification of Ti dental implants by Nd:YVO 4 laser irradiation

    Science.gov (United States)

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

    2007-09-01

    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 6O, Ti 3O 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.

  12. Surface modification of Ti dental implants by Nd:YVO{sub 4} laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Francisco J.C. [Materials Science and Technology Center, Institute of Energetic and Nuclear Research, Box 11049 (05422-970), Sao Paulo (Brazil); Marques, Rodrigo F.C. [Magnetic Materials and Colloid Group, Institute of Chemistry, Sao Paulo State University, Box 355, Araraquara (Brazil); Filho, Edson de A. [Biomaterials Group, Institute of Chemistry, Sao Paulo State University, Box 355, Araraquara (Brazil); Guastaldi, Antonio C. [Biomaterials Group, Institute of Chemistry, Sao Paulo State University, Box 355, Araraquara (Brazil)], E-mail: guastald@iq.unesp.br

    2007-09-30

    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{sub 2} or TiO{sub 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{sub 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 {alpha}Ti, {beta}Ti, Ti{sub 6}O, Ti{sub 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.

  13. Long Range Modification of a Metal Surface Electronic Structure by an Organic Semiconductor

    Science.gov (United States)

    Wang, Jingying; Dougherty, Daniel

    2015-03-01

    In an organic spintronic device the interaction between electrode surface and organic semiconductor layer plays an important role in spin injection at this interface. The antiferromagnetic material Cr(001) is known to have a spin-polarized state near Fermi level that could potentially hybridize with organic molecules. Here we report our STM/STS study of electronic structure at interface between an organic semiconductor, PTCDA, and Cr(001) surface. The study shows that the surface state at Fermi level of Cr(001) can be broadened by PTCDA molecules deposited on the surface due to hybridization of PTCDA molecular orbital and conduction sp band of Cr(001). This indirect modification is not only localized at molecular adsorption sites, but also extends several nm to bare surrounding Cr(001) surface and decays with distance away from PTCDA molecules.

  14. Surface modification of mold steel SKD11 by high current pulsed electron beam

    International Nuclear Information System (INIS)

    Mechanism of surface modification technique by high current pulsed electron beam (HCPEB) was studied with SKD11 steel samples. It was found that crater-like defects would formed on the irradiated surface, the area density of craters and surface roughness decreased with the increasing number of HCPEB pulses. According to the XRD patterns, carbides in the modified surface layers dissolved after several HCPEB pulses and a high-percentage austenite microstructure is formed, but excessive energy deposition resulted in decomposition of the austenite. Treating the samples at 19.8 kV, the wear resistance of modified SKD11 steel improved and the greatest enhancement occurred at 8 pulses. Discussions were given on changes in contents of carbide and austenite in the surface layers. (authors)

  15. Surface modification of a biomedical poly(ether)urethane by a remote air plasma

    Science.gov (United States)

    Gray, J. E.; Norton, P. R.; Griffiths, K.

    2003-07-01

    Plasma modification of polymer surfaces is widely used, but the plasma/polymer interaction is very complex and still not fully understood. In this paper, the interaction of a biomedical poly(ether)urethane with a remote air plasma treatment has been studied. Atomic force microscopy studies show the domain structure of the polymer as well as the absence of any surface roughening due to plasma treatment. Contact angle goniometry shows an improved wettability of the surface after plasma treatment. X-ray photoelectron spectroscopy indicates an increase in CO and CC at the surface, as well as the presence of new functional groups such as alcohols, ketones, aldehydes and imines. There is also evidence that the energy imparted to the polymer during plasma treatment causes surface segregation of polyol segments.

  16. Surface modification of a biomedical poly(ether)urethane by a remote air plasma

    International Nuclear Information System (INIS)

    Plasma modification of polymer surfaces is widely used, but the plasma/polymer interaction is very complex and still not fully understood. In this paper, the interaction of a biomedical poly(ether)urethane with a remote air plasma treatment has been studied. Atomic force microscopy studies show the domain structure of the polymer as well as the absence of any surface roughening due to plasma treatment. Contact angle goniometry shows an improved wettability of the surface after plasma treatment. X-ray photoelectron spectroscopy indicates an increase in C=O and C=C at the surface, as well as the presence of new functional groups such as alcohols, ketones, aldehydes and imines. There is also evidence that the energy imparted to the polymer during plasma treatment causes surface segregation of polyol segments

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

    International Nuclear Information System (INIS)

    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. Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

    Institute of Scientific and Technical Information of China (English)

    YANG Kai; WU Feng; CHEN Shi; ZHANG Cun-zhong

    2007-01-01

    A novel method was applied to the surface modification of the metal hydride(MH) electrode of MH/Ni batteries. Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology, and the effect of the electrode on the performance of MH/Ni batteries was examined. It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance. After surface modification, the discharge capacity at 5C (7.5A) is increased by 212 mA·h and the discharge voltage is increased by 0.11 V, the resistance of the batteries is also decreased by 32%. The batteries with modified electrode exhibit satisfactory durability. The remaining capacity of the modified batteries is 89% of the initial capacity even after 500 cycles. The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.

  19. Rare Earth Ion-Doped Upconversion Nanocrystals: Synthesis and Surface Modification

    Directory of Open Access Journals (Sweden)

    Hongjin Chang

    2014-12-01

    Full Text Available The unique luminescent properties exhibited by rare earth ion-doped upconversion nanocrystals (UCNPs, such as long lifetime, narrow emission line, high color purity, and high resistance to photobleaching, have made them widely used in many areas, including but not limited to high-resolution displays, new-generation information technology, optical communication, bioimaging, and therapy. However, the inherent upconversion luminescent properties of UCNPs are influenced by various parameters, including the size, shape, crystal structure, and chemical composition of the UCNPs, and even the chosen synthesis process and the surfactant molecules used. This review will provide a complete summary on the synthesis methods and the surface modification strategies of UCNPs reported so far. Firstly, we summarize the synthesis methodologies developed in the past decades, such as thermal decomposition, thermal coprecipitation, hydro/solvothermal, sol-gel, combustion, and microwave synthesis. In the second part, five main streams of surface modification strategies for converting hydrophobic UCNPs into hydrophilic ones are elaborated. Finally, we consider the likely directions of the future development and challenges of the synthesis and surface modification, such as the large-scale production and actual applications, stability, and so on, of the UCNPs.

  20. Critical overview of Nitinol surfaces and their modifications for medical applications.

    Science.gov (United States)

    Shabalovskaya, S; Anderegg, J; Van Humbeeck, J

    2008-05-01

    Nitinol, a group of nearly equiatomic shape memory and superelastic NiTi alloys, is being extensively explored for medical applications. Release of Ni in the human body, a potential problem with Nitinol implant devices, has stimulated a great deal of research on its surface modifications and coatings. In order to use any of the developed surfaces in implant designs, it is important to understand whether they really have advantages over bare Nitinol. This paper overviews the current situation, discusses the advantages and disadvantages of new surfaces as well as the limitations of the studies performed. It presents a comprehensive analysis of surface topography, chemistry, corrosion behavior, nickel release and biological responses to Nitinol surfaces modified mechanically or using such methods as etching in acids and alkaline solutions, electropolishing, heat and ion beam treatments, boiling in water and autoclaving, conventional and ion plasma implantations, laser melting and bioactive coating deposition. The analysis demonstrates that the presently developed surfaces vary in thickness from a few nanometers to micrometers, and that they can effectively prevent Ni release if the surface integrity is maintained under strain and if no Ni-enriched sub-layers are present. Whether it is appropriate to use various low temperature pre-treatment protocols (< or = 160 degrees C) developed originally for pure titanium for Nitinol surface modifications and coatings is also discussed. The importance of selection of original Nitinol surfaces with regard to the performance of coatings and comparative performance of controls in the studies is emphasized. Considering the obvious advantages of bare Nitinol surfaces for superelastic implants, details of their preparation are also outlined. PMID:18328796