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Sample records for modified hydrophilic surface

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

    Science.gov (United States)

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

    2014-02-01

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

  2. Structure of DNA-Cationic Surfactant Complexes at Hydrophobically Modified and Hydrophilic Silica Surfaces as Revealed by Neutron Reflectometry

    DEFF Research Database (Denmark)

    Cardenas Gomez, Marite; Wacklin, Hanna; Campbell, Richard A.

    2011-01-01

    with dodecyltrimethylammonium bromide (DTAB) and hexadecyltrimethylammonium bromide (CTAB) on hydrophobic surfaces, where we show that DNA molecules are located on top of a self-assembled surfactant monolayer, with the thickness of the DNA layer and the surfactant DNA ratio determined by the surface coverage of the underlying...... interfacial structures, a higher concentration in relation to its cmc is required for the more soluble DTAB surfactant with a shorter alkyl chain than for CTAB. Our results suggest that the DNA Molecules Will spontaneously form a relatively dense, thin layer on top of a surfactant monolayer (hydrophobic...... surface) or a layer of admicelles (hydrophilic surface) as long as the surface concentration of surfactant is great enough to ensure a high interfacial-charge density. These findings have implications for bioanalytical and nanotechnology applications, which require the deposition of DNA layers with well...

  3. Hydrophilic-impermeable modified polyethylene terephthalate for selective endothelialization

    Science.gov (United States)

    Chetouane, D.; Fafet, J. F.; Barbet, R.; Dieval, F.

    2017-10-01

    The aim of this study was to create a modified polyethylene terephthalate (PET) responding to vascular implants’ requirements, mainly with a surface promoting selective endothelialization. The surface alteration was carried out by hydrophilic functionalization in an alkaline solution with the presence of specific surfactant (TA). The carboxylic groups resulting from this reaction were quantified by colorimetric titration using bleu toluidine O dye (TBO). A single-sided coating process was then optimized to cover the PET surface by micro spherical structures’ polymeric layer. This coating provided to the PET surface high impermeability to the water under a pressure of 120 mmHg and enhanced its hydrophilic property. This spherical topography reduced the adhesion of Mesenchymal Stem Cells (MSC) by 37% and inhibited their proliferation after 3 days by 50%. The hydrophilic functionalized PET (PET-TA) surface decreased the MSC adhesion by 50% and promoted HUVEC attachment with a number twice more important than the number of HUVEC adhered onto non treated-PET.

  4. Study on hydrophilicity of polymer surfaces improved by plasma treatment

    International Nuclear Information System (INIS)

    Lai Jiangnan; Sunderland, Bob; Xue Jianming; Yan, Sha; Zhao Weijiang; Folkard, Melvyn; Michael, Barry D.; Wang Yugang

    2006-01-01

    Surface properties of polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET) samples treated by microwave-induced argon plasma have been studied with contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanned electron microscopy (SEM). It is found that plasma treatment modified the surfaces both in composition and roughness. Modification of composition makes polymer surfaces tend to be highly hydrophilic, which mainly depended on the increase of ratio of oxygen-containing group as same as other papers reported. And this experiment further revealed that C=O bond is Key factor to the improvement of the hydrophilicity of polymer surfaces. Our SEM observation on PET shown that the roughness of the surface has also been improved in micron scale and it has influence on the surface hydrophilicity

  5. Switchable Hydrophobic-Hydrophilic Surfaces

    CERN Document Server

    Bunker, B C; Huber, D L; Kent, M S; Kushmerick, J G; Lopez, G P; Manginell, R P; Méndez, S E; Yim, H

    2002-01-01

    Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swelling transitions in tethered films have been characterized using a wide range of techniques including surface plasmon resonance, attenuated total reflectance infrared spectroscopy, interfacial force microscopy, neutron reflectivity, and theoretical modeling. PNIPAM films have been deployed in integrated microfluidic systems. Switchable PNIPAM films have been investigated for a range of fluidic applications including fluid pumping via surface energy switching and switchable protein traps for pre-concentrating and separating...

  6. Improvement of PET surface hydrophilicity and roughness through blending

    Energy Technology Data Exchange (ETDEWEB)

    Kolahchi, Ahmad Rezaei; Ajji, Abdellah; Carreau, Pierre J. [CREPEC, Chemical Engineering Department, Polytechnique Montreal, 2500 chemin de Polytechnique, Quebec, Montreal (Canada)

    2015-05-22

    Controlling the adhesion of the polymer surface is a key issue in surface science, since polymers have been a commonly used material for many years. The surface modification in this study includes two different aspects. One is to enhance the hydrophilicity and the other is to create the roughness on the PET film surface. In this study we developed a novel and simple approach to modify polyethylene terephthalate (PET) film surface through polymer blending in twin-screw extruder. One example described in the study uses polyethylene glycol (PEG) in polyethylene terephthalate (PET) host to modify a PET film surface. Low content of polystyrene (PS) as a third component was used in the system to increase the rate of migration of PEG to the surface of the film. Surface enrichment of PEG was observed at the polymer/air interface of the polymer film containing PET-PEG-PS whereas for the PET-PEG binary blend more PEG was distributed within the bulk of the sample. Furthermore, a novel method to create roughness at the PET film surface was proposed. In order to roughen the surface of PET film, a small amount of PKHH phenoxy resin to change PS/PET interfacial tension was used. The compatibility effect of PKHH causes the formation of smaller PS droplets, which were able to migrate more easily through PET matrix. Consequently, resulting in a locally elevated concentration of PS near the surface of the film. The local concentration of PS eventually reached a level where a co-continuous morphology occurred, resulting in theinstabilities on the surface of the film.

  7. Transforming plastic surfaces with electrophilic backbones from hydrophobic to hydrophilic.

    Science.gov (United States)

    Kim, Samuel; Bowen, Raffick A R; Zare, Richard N

    2015-01-28

    We demonstrate a simple nonaqueous reaction scheme for transforming the surface of plastics from hydrophobic to hydrophilic. The chemical modification is achieved by base-catalyzed trans-esterification with polyols. It is permanent, does not release contaminants, and causes no optical or mechanical distortion of the plastic. We present contact angle measurements to show successful modification of several types of plastics including poly(ethylene terephthalate) (PET) and polycarbonate (PC). Its applicability to blood analysis is explored using chemically modified PET blood collection tubes and found to be quite satisfactory. We expect this approach will reduce the cost of manufacturing plastic devices with optimized wettability and can be generalized to other types of plastic materials having an electrophilic linkage as its backbone.

  8. Research on the Hydrophilic Modified of LDPE for the New Biological Suspended Filler

    Directory of Open Access Journals (Sweden)

    Kang Weijia

    2016-01-01

    Full Text Available Urban sewage is one of the main pollution sources of the city, which pollute soil, deteriorate the water quality and increase the water shortages and urban load. LDPE is low cost and widely used as the basic material of wastewater treatment, but LDPE’s hydrophilic is not good enough to meet the need of suspended filler in wastewater treatment. In this paper the hydrophilic modified of LDPE for the new biological suspended filler was studied and the preparation and processing technique based on LDPE was researched. The hydrophilic and mechanic performance of the hydrophilic modified materials was tested. Results shown that the new type of hydrophilic modified materials has good hydrophilic and meets the demand of urban sewage treatment. The research on the new suspended filler materials has great meaning in solving the problem of urban sewage and recycling.

  9. Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfaces

    DEFF Research Database (Denmark)

    Hansson, Petra M; Claesson, Per M.; Swerin, Agne

    2013-01-01

    Friction forces have long been associated with the famous Amontons' rule that states that the friction force is linearly dependent on the applied normal load, with the proportionality constant being known as the friction coefficient. Amontons' rule is however purely phenomenological and does...... not in itself provide any information on why the friction coefficient is different for different material combinations. In this study, friction forces between a colloidal probe and nanostructured particle coated surfaces in an aqueous environment exhibiting different roughness length scales were measured...... by utilizing the atomic force microscope (AFM). The chemistry of the surfaces and the probe was varied between hydrophilic silica and hydrophobized silica. For hydrophilic silica surfaces, the friction coefficient was significantly higher for the particle coated surfaces than on the flat reference surface. All...

  10. Micro- and nanoscale characterization of hydrophobic and hydrophilic leaf surfaces

    International Nuclear Information System (INIS)

    Bhushan, Bharat; Jung, Yong Chae

    2006-01-01

    Superhydrophobic surfaces as well as low adhesion and friction are desirable for various industrial applications. Certain plant leaves are known to be hydrophobic in nature due to their roughness and the presence of a thin wax film on the surface of the leaf. The purpose of this study is to fully characterize the leaf surfaces on the micro- and nanoscale while separating out the effects of the micro- and the nanobumps of hydrophobic leaves on the hydrophobicity. Hydrophilic leaves were also studied to better understand the role of wax and roughness. Furthermore, the adhesion and friction properties of hydrophobic and hydrophilic leaves were studied. Using an optical profiler and an atomic/friction force microscope (AFM/FFM), measurements were made to fully characterize the leaf surfaces. It is shown that the nanobumps play a more important role than the microbumps in the hydrophobic nature as well as friction of the leaf. This study will be useful in developing superhydrophobic surfaces

  11. Fabrication of zero contact angle ultra-super hydrophilic surfaces.

    Science.gov (United States)

    Jothi Prakash, C G; Clement Raj, C; Prasanth, R

    2017-06-15

    Zero contact angle surfaces have been created with the combined effect of nanostructure and UV illumination. The contact angle of titanium surface has been optimized to 3.25°±1°. with nanotubular structures through electrochemical surface modification. The porosity and surface energy of tubular TiO 2 layer play critical role over the surface wettability and the hydrophilicity of the surface. The surface free energy has been enhanced from 23.72mJ/m 2 (bare titanium surface) to 87.11mJ/m 2 (nanotubular surface). Similar surface with TiO 2 nanoparticles coating shows superhydrophilicity with contact angle up to 5.63°±0.95°. This implies liquid imbibition and surface curvature play a crucial role in surface hydrophilicity. The contact angle has been further reduced to 0°±0.86° by illuminating the surface with UV radiation. Results shows that by tuning the nanotube morphology, highly porous surfaces can be fabricated to reduce contact angle and enhance wettability. This study provides an insight into the inter-relationship between surface structural factors and ultra-superhydrophilic surfaces which can help to optimize thermal hydraulic and self cleaning surfaces. Copyright © 2017. Published by Elsevier Inc.

  12. Patterned hydrophobic and hydrophilic surfaces of ultra-smooth nanocrystalline diamond layers

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, M., E-mail: michael.mertens@uni-ulm.de [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Mohr, M.; Brühne, K.; Fecht, H.J. [Institute of Micro and Nanomaterials, Ulm University, 89081 Ulm (Germany); Łojkowski, M.; Święszkowski, W. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland); Łojkowski, W. [Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw (Poland)

    2016-12-30

    Highlights: • Hydrophobic and hydrophilic properties on fluorine-, hydrogen- and oxygen- terminated ultra-nanocrystalline diamond films. • Micropatterned - multi-terminated layers with both hydrophobic and hydrophilic areas on one sample. • Visualization of multi-terminated surfaces by e.g. SEM and LFM. • Roughness and friction investigations on different terminated surfaces. • Smooth and biocompatible surfaces with same roughness regardless of hydrophobicity for microbiological investigations. - Abstract: In this work, we show that ultra nanocrystalline diamond (UNCD) surfaces have been modified to add them hydrophobic and hydrophilic properties. The nanocrystalline diamond films were deposited using the hot filament chemical vapor deposition (HFCVD) technique. This allows growing diamond on different substrates which can be even 3D or structured. Silicon and, for optical applications, transparent quartz glass are the preferred substrates for UNCD layers growth. Fluorine termination leads to strong hydrophobic properties as indicated by a high contact angle for water of more than 100°. Hydrogen termination shows lesser hydrophobic behavior. Hydrophilic characteristics has been realised with oxygen termination. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) measurements confirm the oxygen and fluorine- termination on the nanocrystalline diamond surface. Further, by micropatterning using photolithography, multi-terminated layers have been created with both hydrophobic and hydrophilic areas. In addition, we have shown that retermination is achieved, and the properties of the surface have been changed from hydrophobic to hydrophilic and vice versa. Micro- roughness and stress in the grown film influences slightly the wetting angle as well. The opportunity to realize local differences in hydrophobicity on nanocrystalline diamond layers, in any size or geometry, offers interesting applications for example in

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-01

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

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

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  16. Enhanced Hydrophilicity and Protein Adsorption of Titanium Surface by Sodium Bicarbonate Solution

    Directory of Open Access Journals (Sweden)

    Shengnan Jia

    2015-01-01

    Full Text Available The aim of this study was to investigate a novel and convenient method of chemical treatment to modify the hydrophilicity of titanium surfaces. Sand-blasted and acid-etched (SLA titanium surfaces and machined titanium surfaces were treated with sodium bicarbonate (NaHCO3 solution. The wetting behavior of both kinds of surfaces was measured by water contact angle (WCA test. The surface microstructure was assessed with scanning electron microscopy (SEM and three-dimensional (3D optical microscopy. The elemental compositions of the surfaces were analyzed by X-ray photoelectron spectroscopy (XPS. The protein adsorption analysis was performed with fibronectin. Results showed that, after 1 M NaHCO3 treatment, the hydrophilicity of both SLA and machined surfaces was enhanced. No significant microstructural change presented on titanium surfaces after NaHCO3 treatment. The deprotonation and ion exchange activities might cause the enhanced hydrophilicity of titanium surfaces. The increased protein adsorption of NaHCO3-treated SLA surfaces might indicate their improved tissue-integration in clinical use.

  17. Simultaneous and long-lasting hydrophilization of inner and outer wall surfaces of polytetrafluoroethylene tubes by transferring atmospheric pressure plasmas

    International Nuclear Information System (INIS)

    Chen, Faze; Song, Jinlong; Huang, Shuai; Xu, Wenji; Sun, Jing; Liu, Xin; Xu, Sihao; Xia, Guangqing; Yang, Dezheng

    2016-01-01

    Plasma hydrophilization is a general method to increase the surface free energy of materials. However, only a few works about plasma modification focus on the hydrophilization of tube inner and outer walls. In this paper, we realize simultaneous and long-lasting plasma hydrophilization on the inner and outer walls of polytetrafluoroethylene (PTFE) tubes by atmospheric pressure plasmas (APPs). Specifically, an Ar atmospheric pressure plasma jet (APPJ) is used to modify the PTFE tube’s outer wall and meanwhile to induce transferred He APP inside the PTFE tube to modify its inner wall surface. The optical emission spectrum (OES) shows that the plasmas contain many chemically active species, which are known as enablers for various applications. Water contact angle (WCA) measurements, x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) are used to characterize the plasma hydrophilization. Results demonstrate that the wettability of the tube walls are well improved due to the replacement of the surface fluorine by oxygen and the change of surface roughness. The obtained hydrophilicity decreases slowly during more than 180 d aging, indicating a long-lasting hydrophilization. The results presented here clearly demonstrate the great potential of transferring APPs for surface modification of the tube’s inner and outer walls simultaneously. (paper)

  18. A sol-gel-modified poly(methyl methacrylate) electrophoresis microchip with a hydrophilic channel wall.

    Science.gov (United States)

    Chen, Gang; Xu, Xuejiao; Lin, Yuehe; Wang, Joseph

    2007-01-01

    A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was approximately 27.4 degrees compared with approximately 66.3 degrees for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13x10(-4) cm2 V(-1) s(-1) for the native-PMMA channel to 4.86x10(-4) cm2 V(-1) s(-1) for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74,882.3 m(-1) compared with 14,730.5 m(-1) for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.

  19. Molecular Dynamics Simulations of Water Droplets On Hydrophilic Silica Surfaces

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

    2009-01-01

    and DNA microarrays technologies.Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water, at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle computations...... dynamics (MD) simulations of a hydrophilic air-water-silica system using the MD package FASTTUBE. We employ quantum chemistry calculation to obtain air-silica interaction parameters for the simulations. Our simulations are based in the following force fields: i) The silica-silica interaction is based...... of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems. For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence of air. Hence...

  20. Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

    International Nuclear Information System (INIS)

    Mu Lijun; Zhao Wenzhen

    2009-01-01

    A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 μg/cm 2 was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.

  1. Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

    Energy Technology Data Exchange (ETDEWEB)

    Mu Lijun, E-mail: l.j.mu@hotmail.com [School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Zhao Wenzhen [School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2009-05-30

    A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 {mu}g/cm{sup 2} was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.

  2. Super-hydrophilicity of hydroxy modified poly(m-phenylenediamine) aerogel for separation of oil/water and biocompatibility

    Science.gov (United States)

    Wang, Gang; Liu, Zhiduo; Zhang, Nan; Li, Jiurong; Xu, Anli; Xiang, Pengcheng; Hu, Xurui; Guo, Qinglei; Chen, Da

    2018-04-01

    We demonstrate the ultra-light weight and super-hydrophilic hydroxyl modified poly (m-phenylenediamine) (Hy-PmPD) aerogel by utilizing simple oxygen plasma treatment. The average pore size and specific surface area are obtained as 5.21 nm and 671 m2 g‑1, respectively. Due to the large amount of oxygen-containing groups (e.g., C–OH and N–OH), the contact angle of Hy-PmPD for water is about 7.2°, which indicates the super-hydrophilic ability of Hy-PmPD. The large surface area and super-hydrophilic nature of ultra- light weight Hy-PmPD aerogel conclusively certify that high absorption capacities and ultrafast absorption rate for water. As a result, the Hy-PmPD aerogel enables to separate crude oil and water. Additionally, the Hy-PmPD aerogel indicates good biocompatibility that can be implanted as the bio-platform for monitoring the cell culture behavior. This work may provide a facile and effective strategy for the applications in the absorption or removal of organics, particularly in environmental protection, pollution control, as well as noninvasive to the microflora.

  3. A facile strategy for the fabrication of a bioinspired hydrophilic-superhydrophobic patterned surface for highly efficient fog-harvesting

    KAUST Repository

    Wang, Yuchao

    2015-08-10

    Fog water collection represents a meaningful effort in the places where regular water sources, including surface water and ground water, are scarce. Inspired by the amazing fog water collection capability of Stenocara beetles in the Namib Desert and based on the recent work in biomimetic water collection, this work reported a facile, easy-to-operate, and low-cost method for the fabrication of hydrophilic-superhydrophobic patterned hybrid surface toward highly efficient fog water collection. The essence of the method is incorporating a (super)hydrophobically modified metal-based gauze onto the surface of a hydrophilic polystyrene (PS) flat sheet by a simple lab oven-based thermal pressing procedure. The produced hybrid patterned surfaces consisted of PS patches sitting within the holes of the metal gauzes. The method allows for an easy control over the pattern dimension (e.g., patch size) by varying gauze mesh size and thermal pressing temperature, which is then translated to an easy optimization of the ultimate fog water collection efficiency. Given the low-cost and wide availability of both PS and metal gauze, this method has a great potential for scaling-up. The results showed that the hydrophilic-superhydrophobic patterned hybrid surfaces with a similar pattern size to Stenocara beetles’s back pattern produced significantly higher fog collection efficiency than the uniformly (super)hydrophilic or (super)hydrophobic surfaces. This work contributes to general effort in fabricating wettability patterned surfaces and to atmospheric water collection for direct portal use.

  4. Controlled surface morphology and hydrophilicity of polycaprolactone toward human retinal pigment epithelium cells

    International Nuclear Information System (INIS)

    Shahmoradi, Saleheh; Yazdian, Fatemeh; Tabandeh, Fatemeh; Soheili, Zahra-Soheila; Hatamian Zarami, Ashraf Sadat; Navaei-Nigjeh, Mona

    2017-01-01

    Applying scaffolds as a bed to enhance cell proliferation and even differentiation is one of the treatment of retina diseases such as age-related macular degeneration (AMD) which deteriorating photoreceptors and finally happening blindness. In this study, aligned polycaprolactone (PCL) nanofibers were electrospun and at different conditions and their characteristics were measured by scanning electron microscope (SEM) and contact angle. Response surface methodology (RSM) was used to optimize the diameter of fabricated nanofibers. Two factors as solution concentration and voltage value were considered as independent variables and their effects on nanofibers' diameters were evaluated by central composite design and the optimum conditions were obtained as 0.12 g/mL and 20 kV, respectively. In order to decrease the hydrophobicity of PCL, the surface of the fabricated scaffolds was modified by alkaline hydrolysis method. Contact time of the scaffolds and alkaline solution and concentration of alkaline solution were optimized using Box Behnken design and (120 min and 5 M were the optimal, respectively). Contact angle measurement showed the high hydrophilicity of treated scaffolds (with contact angle 7.48°). Plasma surface treatment was applied to compare the effect of using two kinds of surface modification methods simultaneously on hydrolyzed scaffolds. The RPE cells grown on scaffolds were examined by immunocytochemistry (ICC), MTT and continuous inspection of cellular morphology. Interestingly, Human RPE cells revealed their characteristic morphology on hydrolyzed scaffold well. As a result, we introduced a culture substrate with low diameter (185.8 nm), high porosity (82%) and suitable hydrophilicity (with contact angle 7.48 degree) which can be promising for hRPE cell transplantation. - Highlights: • Dimethylformamide (DMF) has significant effect on reduction of fibers' diameter. • Having high hydrophilicity by alkaline hydrolysis • Suitable

  5. Controlled surface morphology and hydrophilicity of polycaprolactone toward human retinal pigment epithelium cells

    Energy Technology Data Exchange (ETDEWEB)

    Shahmoradi, Saleheh; Yazdian, Fatemeh [Department of Life Science Engineering, Faculty of New sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Tabandeh, Fatemeh, E-mail: taban_f@nigeb.ac.ir [Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran (Iran, Islamic Republic of); Soheili, Zahra-Soheila [Department of Molecular Medicine, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran (Iran, Islamic Republic of); Hatamian Zarami, Ashraf Sadat [Department of Life Science Engineering, Faculty of New sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Navaei-Nigjeh, Mona [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2017-04-01

    Applying scaffolds as a bed to enhance cell proliferation and even differentiation is one of the treatment of retina diseases such as age-related macular degeneration (AMD) which deteriorating photoreceptors and finally happening blindness. In this study, aligned polycaprolactone (PCL) nanofibers were electrospun and at different conditions and their characteristics were measured by scanning electron microscope (SEM) and contact angle. Response surface methodology (RSM) was used to optimize the diameter of fabricated nanofibers. Two factors as solution concentration and voltage value were considered as independent variables and their effects on nanofibers' diameters were evaluated by central composite design and the optimum conditions were obtained as 0.12 g/mL and 20 kV, respectively. In order to decrease the hydrophobicity of PCL, the surface of the fabricated scaffolds was modified by alkaline hydrolysis method. Contact time of the scaffolds and alkaline solution and concentration of alkaline solution were optimized using Box Behnken design and (120 min and 5 M were the optimal, respectively). Contact angle measurement showed the high hydrophilicity of treated scaffolds (with contact angle 7.48°). Plasma surface treatment was applied to compare the effect of using two kinds of surface modification methods simultaneously on hydrolyzed scaffolds. The RPE cells grown on scaffolds were examined by immunocytochemistry (ICC), MTT and continuous inspection of cellular morphology. Interestingly, Human RPE cells revealed their characteristic morphology on hydrolyzed scaffold well. As a result, we introduced a culture substrate with low diameter (185.8 nm), high porosity (82%) and suitable hydrophilicity (with contact angle 7.48 degree) which can be promising for hRPE cell transplantation. - Highlights: • Dimethylformamide (DMF) has significant effect on reduction of fibers' diameter. • Having high hydrophilicity by alkaline hydrolysis • Suitable

  6. Surface hydrophilicity of PLGA fibers governs in vitro mineralization and osteogenic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Minnah; Arora, Aditya; Katti, Dhirendra S., E-mail: dsk@iitk.ac.in

    2014-12-01

    Interfacial properties of biomaterials play an important role in governing their interaction with biological microenvironments. This work investigates the role of surface hydrophilicity of electrospun poly(lactide-co-glycolide) (PLGA) fibers in determining their biological response. For this, PLGA is blended with varying amounts of Pluronic®F-108 and electrospun to fabricate microfibers with varying surface hydrophilicity. The results of mineralization study in simulated body fluid (SBF) demonstrate a significant enhancement in mineralization with an increase in surface hydrophilicity. While presence of serum proteins in SBF reduces absolute mineral content, mineralization continues to be higher on samples with higher surface hydrophilicity. The results from in vitro cell culture studies demonstrate a marked improvement in mesenchymal stem cell —adhesion, elongation, proliferation, infiltration, osteogenic differentiation and matrix mineralization on hydrophilized fibers. Therefore, hydrophilized PLGA fibers are advantageous both in terms of mineralization and elicitation of favorable cell response. Since most of the polymeric materials being used in orthopedics are hydrophobic in nature, the results from this study have strong implications in the future design of interfaces of such hydrophobic materials. In addition, the work proposes a facile method for the modification of electrospun fibers of hydrophobic polymers by blending with a poloxamer for improved bone tissue regeneration. - Highlights: • Surface hydrophilicity of PLGA modulated by blending with Pluronic F-108. • Hydrophilized fibers support better in vitro mineralization. • Mineralization trends retained in the presence of adsorbed serum proteins. • Hydrophilized fibers promote better cell adhesion and proliferation. • Hydrophilized fibers also enable better osteogenic differentiation.

  7. Improvement of antifouling performances for modified PVDF ultrafiltration membrane with hydrophilic cellulose nanocrystal

    Science.gov (United States)

    Lv, Jinling; Zhang, Guoquan; Zhang, Hanmin; Zhao, Chuanqi; Yang, Fenglin

    2018-05-01

    Hydrophilic cellulose nanocrystal (CNC) was incorporated into hydrophobic poly(vinylidene fluoride) (PVDF) membrane via phase inversion process to improve membrane antifouling property. The effects of CNC on membrane morphology, hydrophilicity, permeability and antifouling property were investigated in-detail. Results indicated that the introduction of CNC into PVDF membrane enhanced the permeability by optimizing membrane microstructure and improving membrane hydrophilicity. A higher pure water flux of 206.9 L m-2 h-1 was achieved for CNC/PVDF membrane at 100 kPa, which was 20 times that of PVDF membrane (9.8 L m-2 h-1). In bovine serum albumin filtration measurements, the permeation flux and flux recovery ratio of CNC/PVDF membrane were increased remarkably, while the irreversible fouling-resistance of CNC/PVDF membrane decreased by 48.8%. These results indicated that the CNC/PVDF membrane possessed superior antifouling property due to the hydrophilicity of CNC that formed a hydration layer on the membrane surface to effectively reduce contaminants adsorption/deposition.

  8. Surface modification of commercial seawater reverse osmosis membranes by grafting of hydrophilic monomer blended with carboxylated multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vatanpour, Vahid, E-mail: vahidvatanpour@khu.ac.ir; Zoqi, Naser

    2017-02-28

    Highlights: • A commercial PA RO membrane was modified by grafting of hydrophilic acrylic acid. • COOH-MWCNTs were mixed in grafting layer to increase permeability and antifouling. • However, more increase of CNTs caused in reduction of flux of the membranes. • Effect of acrylic acid amount, contact time and curing time was optimized. - Abstract: In this study, modification of commercial seawater reverse osmosis membranes was carried out with simultaneous use of surface grafting and nanoparticle incorporation. Membrane grafting with a hydrophilic acrylic acid monomer and thermal initiator was used to increase membrane surface hydrophilicity. The used nanomaterial was carboxylated multiwalled carbon nanotubes (MWCNTs), which were dispersed in the grafting solution and deposited on membrane surface to reduce fouling by creating polymer brushes and hydrodynamic resistance. Effectiveness of the grafting process (formation of graft layer on membrane surface) was proved by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Increase of membrane surface hydrophilicity was approved with contact angle test. First, the grafting was performed on the membrane surfaces with different monomer concentrations, various contact times and several membrane curing times (three variables for optimization). The modified membranes were tested by a cross-flow setup using saline solution for permeability and rejection tests, and bovine serum albumin (BSA) solution for fouling test. The results showed that the modified membranes with 0.75 M of monomer, 3 min contact time and 80 min curing time in an oven at 50 °C presented the highest flux and lowest rejection decline related to the commercial reverse osmosis membrane. In the next step, the optimum grafting condition was selected and the nanotubes with different weight percentages were dispersed in the acrylic acid monomer solution. The membrane containing 0.25 wt% COOH-MWCNTs showed the

  9. Surface modification of commercial seawater reverse osmosis membranes by grafting of hydrophilic monomer blended with carboxylated multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Vatanpour, Vahid; Zoqi, Naser

    2017-01-01

    Highlights: • A commercial PA RO membrane was modified by grafting of hydrophilic acrylic acid. • COOH-MWCNTs were mixed in grafting layer to increase permeability and antifouling. • However, more increase of CNTs caused in reduction of flux of the membranes. • Effect of acrylic acid amount, contact time and curing time was optimized. - Abstract: In this study, modification of commercial seawater reverse osmosis membranes was carried out with simultaneous use of surface grafting and nanoparticle incorporation. Membrane grafting with a hydrophilic acrylic acid monomer and thermal initiator was used to increase membrane surface hydrophilicity. The used nanomaterial was carboxylated multiwalled carbon nanotubes (MWCNTs), which were dispersed in the grafting solution and deposited on membrane surface to reduce fouling by creating polymer brushes and hydrodynamic resistance. Effectiveness of the grafting process (formation of graft layer on membrane surface) was proved by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Increase of membrane surface hydrophilicity was approved with contact angle test. First, the grafting was performed on the membrane surfaces with different monomer concentrations, various contact times and several membrane curing times (three variables for optimization). The modified membranes were tested by a cross-flow setup using saline solution for permeability and rejection tests, and bovine serum albumin (BSA) solution for fouling test. The results showed that the modified membranes with 0.75 M of monomer, 3 min contact time and 80 min curing time in an oven at 50 °C presented the highest flux and lowest rejection decline related to the commercial reverse osmosis membrane. In the next step, the optimum grafting condition was selected and the nanotubes with different weight percentages were dispersed in the acrylic acid monomer solution. The membrane containing 0.25 wt% COOH-MWCNTs showed the

  10. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, N.P.; Norde, W.; Meil, H.C.; Busscher, H.J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F-prev) and to detach adhering bacteria (F-det) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  11. Hydrophilic film polymerized on the inner surface of PMMA tube by an atmospheric pressure plasma jet

    Science.gov (United States)

    Yin, Mengmeng; Huang, Jun; Yu, Jinsong; Chen, Guangliang; Qu, Shanqing

    2017-07-01

    Polymethyl methacrylate (PMMA) tube is widely used in biomedical and mechanical engineering fields. However, it is hampered for some special applications as the inner surface of PMMA tube exhibts a hydrophobic characteristic. The aim of this work is to explore the hydrophilic modification of the inner surface of the PMMA tubes using an atmospheric pressure plasma jet (APPJ) system that incorporates the acylic acid monomer (AA). Polar groups were grafted onto the inner surface of PMMA tube via the reactive radicals (•OH, •H, •O) generated in the Ar/O2/AA plasma, which were observed by the optical emission spectroscopy (OES). The deposition of the PAA thin layer on the PMMA surface was verified through the ATR-FTIR spectra, which clearly showed the strengthened stretching vibration of the carbonyl group (C=O) at 1700 cm-1. The XPS data show that the carbon ratios of C-OH/R and COOH/R groups increased from 9.50% and 0.07% to 13.49% and 17.07% respectively when a discharge power of 50 W was used in the APPJ system. As a result, the static water contat angle (WCA) of the modified inner surface of PMMA tube decreased from 100° to 48°. Furthermore, the biocompatibility of the APP modified PMMA tubes was illustrated by the study of the adhesion of the cultured MC3T3-E1 osteocyte cells, which exhibted a significantly enhanced adhesion density.

  12. Controlled surface morphology and hydrophilicity of polycaprolactone toward human retinal pigment epithelium cells.

    Science.gov (United States)

    Shahmoradi, Saleheh; Yazdian, Fatemeh; Tabandeh, Fatemeh; Soheili, Zahra-Soheila; Hatamian Zarami, Ashraf Sadat; Navaei-Nigjeh, Mona

    2017-04-01

    Applying scaffolds as a bed to enhance cell proliferation and even differentiation is one of the treatment of retina diseases such as age-related macular degeneration (AMD) which deteriorating photoreceptors and finally happening blindness. In this study, aligned polycaprolactone (PCL) nanofibers were electrospun and at different conditions and their characteristics were measured by scanning electron microscope (SEM) and contact angle. Response surface methodology (RSM) was used to optimize the diameter of fabricated nanofibers. Two factors as solution concentration and voltage value were considered as independent variables and their effects on nanofibers' diameters were evaluated by central composite design and the optimum conditions were obtained as 0.12g/mL and 20kV, respectively. In order to decrease the hydrophobicity of PCL, the surface of the fabricated scaffolds was modified by alkaline hydrolysis method. Contact time of the scaffolds and alkaline solution and concentration of alkaline solution were optimized using Box Behnken design and (120min and 5M were the optimal, respectively). Contact angle measurement showed the high hydrophilicity of treated scaffolds (with contact angle 7.48°). Plasma surface treatment was applied to compare the effect of using two kinds of surface modification methods simultaneously on hydrolyzed scaffolds. The RPE cells grown on scaffolds were examined by immunocytochemistry (ICC), MTT and continuous inspection of cellular morphology. Interestingly, Human RPE cells revealed their characteristic morphology on hydrolyzed scaffold well. As a result, we introduced a culture substrate with low diameter (185.8nm), high porosity (82%) and suitable hydrophilicity (with contact angle 7.48 degree) which can be promising for hRPE cell transplantation. Copyright © 2016. Published by Elsevier B.V.

  13. New approach of long-term modification of Topas® to acquire surface hydrophilicity for chromosome spreading

    DEFF Research Database (Denmark)

    Mednova, Olga; Kwasny, Dorota; Rozlosnik, Noemi

    2014-01-01

    as a description of the optimal cleaning procedure and storage conditions to maintain the modified surface. Three minutes of oxygen plasma activation followed by 4 min of acrylic acid UV-photografting at 50 °C leads to the most stable hydrophilicity that was characterized by an initial water contact angle of 53.......5° ± 1.2°. Storage of the modified material in cold water at 4 °C and refraining from ultrasonic cleaning limit water contact angle increase to 5° over 30 days. In comparison with pristine hydrophobic Topas, the proposed treatment improves chromosome spreading ability significantly....

  14. Free surface entropic lattice Boltzmann simulations of film condensation on vertical hydrophilic plates

    DEFF Research Database (Denmark)

    Hygum, Morten Arnfeldt; Karlin, Iliya; Popok, Vladimir

    2015-01-01

    A model for vapor condensation on vertical hydrophilic surfaces is developed using the entropic lattice Boltzmann method extended with a free surface formulation of the evaporation–condensation problem. The model is validated with the steady liquid film formation on a flat vertical wall. It is sh......A model for vapor condensation on vertical hydrophilic surfaces is developed using the entropic lattice Boltzmann method extended with a free surface formulation of the evaporation–condensation problem. The model is validated with the steady liquid film formation on a flat vertical wall...

  15. Bond-Strengthening in Staphylococcal Adhesion to Hydrophilic and Hydrophobic Surfaces Using Atomic Force Microscopy

    NARCIS (Netherlands)

    Boks, N.P.; Busscher, H.J.; Mei, van der H.C.; Norde, W.

    2008-01-01

    Time-dependent bacterial adhesion forces of four strains of Staphylococcus epidermidis to hydrophobic and hydrophilic surfaces were investigated. Initial adhesion forces differed significantly between the two surfaces and hovered around -0.4 nN. No unambiguous effect of substratum surface

  16. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  17. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, Leonard C. [State Univ. of New York (SUNY), Stony Brook, NY (United States); Ishida, Takanobu [State Univ. of New York (SUNY), Stony Brook, NY (United States)

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between -0.24 and +1.25 VSCE while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-ρ-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  18. Calcification of Hydrophilic Acrylic Intraocular Lenses With a Hydrophobic Surface: Laboratory Analysis of 6 Cases.

    Science.gov (United States)

    Gartaganis, Sotirios P; Prahs, Philipp; Lazari, Eftichia D; Gartaganis, Panos S; Helbig, Horst; Koutsoukos, Petros G

    2016-08-01

    To investigate the nature and characteristic features of deposits causing opacification of intraocular lenses (IOLs) based on the examination of clinical findings using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) analysis. Retrospective, observational case series. This is a multicenter study of 6 hydrophilic acrylic IOLs (Lentis LS-502-1; Oculentis GmbH, Berlin, Germany) with a hydrophobic surface that were explanted from 5 patients because of opacification. Three patients had an uncomplicated phacoemulsification. One patient underwent combined phacoemulsification and pars plana vitrectomy for retinal detachment and later silicone oil endotamponade owing to redetachment. The last patient had a pars plana vitrectomy and silicone oil instillation combined with phacoemulsification for tractive retinal detachment and diabetic retinopathy. The explanted lenses were submitted to our laboratory and were examined by SEM and EDX in order to identify the morphologic features and the composition of the deposits. SEM and EDX analyses confirmed the presence of calcific deposits in the interior of the opacified hydrophilic IOLs, with a pattern showing the formation of lumps on the surface. The lumps were due to subsurface formation of calcium phosphate crystalline deposits. The crystallite clusters seemed to diffuse from the IOL interior to the surface. We demonstrated the calcification pattern of the hydrophilic IOL (Lentis LS-502-1) with a hydrophobic surface. Although hydrophilic acrylic lenses have a hydrophobic surface, the development of calcification is a possible threat initiating from the hydrophilic subsurface of the IOLs. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns.

    Science.gov (United States)

    Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

    2015-11-06

    Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

  20. The hydrophobic effect: Molecular dynamics simulations of water confined between extended hydrophobic and hydrophilic surfaces

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Mouritsen, Ole G.; Peters, Günther H.J.

    2004-01-01

    Structural and dynamic properties of water confined between two parallel, extended, either hydrophobic or hydrophilic crystalline surfaces of n-alkane C36H74 or n-alcohol C35H71OH, are studied by molecular dynamics simulations. Electron density profiles, directly compared with corresponding......-correlation functions reveal that water molecules have characteristic diffusive behavior and orientational ordering due to the lack of hydrogen bonding interactions with the surface. These observations suggest that the altered dynamical properties of water in contact with extended hydrophobic surfaces together...... at both surfaces. The ordering is characteristically different between the surfaces and of longer range at the hydrophilic surface. Furthermore, the dynamic properties of water are different at the two surfaces and different from the bulk behavior. In particular, at the hydrophobic surface, time...

  1. Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

    Science.gov (United States)

    Mondal, Bikash; Mac Giolla Eain, Marc; Xu, QianFeng; Egan, Vanessa M; Punch, Jeff; Lyons, Alan M

    2015-10-28

    Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat

  2. Comparison of the Fouling Release Properties of Hydrophobic Fluorinated and Hydrophilic PEGylated Block Copolymer Surfaces

    International Nuclear Information System (INIS)

    Krishnan, S.; Wang, N.; Ober, C.; Finlay, J.; Callow, M.; Callow, J.; Hexemer, A.; Sohn, K.; Kramer, E.; Fischer, D.

    2006-01-01

    To understand the role of surface wettability in adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom Navicula and sporelings (young plants) of the green macroalga Ulva to an underwater surface is mainly by interactions between the surface and the adhesive exopolymers, which the cells secrete upon settlement and during subsequent colonization and growth. Two types of block copolymers, one with poly(ethylene glycol) side-chains and the other with liquid crystalline, fluorinated side-chains, were used to prepare the hydrophilic and hydrophobic surfaces, respectively. The formation of a liquid crystalline smectic phase in the latter inhibited molecular reorganization at the surface, which is generally an issue when a highly hydrophobic surface is in contact with water. The adhesion strength was assessed by the fraction of settled cells (Navicula) or biomass (Ulva) that detached from the surface in a water flow channel with a wall shear stress of 53 Pa. The two species exhibited opposite adhesion behavior on the same sets of surfaces. While Navicula cells released more easily from hydrophilic surfaces, Ulva sporelings showed higher removal from hydrophobic surfaces. This highlights the importance of differences in cell-surface interactions in determining the strength of adhesion of cells to substrates

  3. Influence of roughness on capillary forces between hydrophilic surfaces

    NARCIS (Netherlands)

    van Zwol, P. J.; Palasantzas, G.; De Hosson, J. Th. M.

    Capillary forces have been measured by atomic force microscopy in the plate-sphere setup between gold, borosilicate glass, GeSbTe, titanium, and UV-irradiated amorphous titanium-dioxide surfaces. The force measurements were performed as a function contact time and surface roughness in the range

  4. Pool boiling of nanoparticle-modified surface with interlaced wettability

    KAUST Repository

    Hsu, Chin-Chi; Su, Tsung-Wen; Chen, Ping-Hei

    2012-01-01

    This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface. In addition, this study observed that critical heat flux was higher when the contact angle difference between the plain surface and the modified region was smaller. © 2012 Hsu et al.

  5. Hydrophilic/hydrophobic surface modification impact on colloid lithography: Schottky-like defects, dislocation, and ideal distribution

    Science.gov (United States)

    Burtsev, Vasilii; Marchuk, Valentina; Kugaevskiy, Artem; Guselnikova, Olga; Elashnikov, Roman; Miliutina, Elena; Postnikov, Pavel; Svorcik, Vaclav; Lyutakov, Oleksiy

    2018-03-01

    Nano-spheres lithography is actually considered as a powerful tool to manufacture various periodic structures with a wide potential in the field of nano- and micro-fabrication. However, during self-assembling of colloid microspheres, various defects and mismatches can appear. In this work the size and quality of single-domains of closed-packed polystyrene (PS), grown up on thin Au layers modified by hydrophilic or hydrophobic functional groups via diazonium chemistry was studied. The effects of the surface modification on the quality and single-domain size of polystyrene (PS) microspheres array were investigated and discussed. Modified surfaces were characterized using the AFM and wettability tests. PS colloidal suspension was deposited using the drop evaporation method. Resulted PS microspheres array was characterized using the SEM, AFM and confocal microscopy technique.

  6. Surface-modified electrodes (SME)

    NARCIS (Netherlands)

    Schreurs, J.P.G.M.; Barendrecht, E.

    1984-01-01

    This review deals with the literature (covered up to August 1983), the characterization and the applications of Surface-Modified Electrodes (SME). As a special class of SME's, the Enzyme-Modified Electrode (EME) is introduced. Three types of modification procedures are distinguished; i.e. covalent

  7. Environmentally benign electroless nickel plating using supercritical carbon-dioxide on hydrophilically modified acrylonitrile-butadiene-styrene

    Science.gov (United States)

    Tengsuwan, Siwach; Ohshima, Masahiro

    2014-08-01

    Electroless Ni-P plating using supercritical carbon dioxide (scCO2) in conjunction with copolymer-based hydrophilic modification was applied to an acrylonitrile-butadiene-styrene (ABS) substrate. The surface of ABS substrate was hydrophilically modified by blending with a multi-block copolymer, poly(ether-ester-amide)s (PEEA), in injection molding process. The substrate was then impregnated with Pd(II)-hexafluoroacetylacetonate, Pd(hfa)2, using scCO2, followed by the electroless plating reaction. ABS/PEEA substrates with different PEEA to ABS blend ratios and different volume ratios of butadiene to the styrene-acrylonitrile copolymer (SAN) matrix were prepared to investigate how the dispersed PEEA and butadiene domains affected the blend morphology and the adhesive strength of the plating metal-to-polymer contact. Increasing the PEEA copolymer to ABS blend ratio increased the mass transfer rate of the plating solution in the ABS substrate. Consequently, the metal-polymer composite layer became thicker, which increased the adhesive strength of the metal-to-polymer contact because of the anchoring effect. The butadiene domains appeared to attract the Pd catalyst precursor, and thus, the proportion of butadiene in the ABS matrix also affected the adhesive strength of the contact between the metal layer and the substrate. The ABS substrate was successfully plated with a Ni-P metal layer with an average adhesive strength of 9.1 ± 0.5 N cm-1 by choosing appropriate ABS/PEEA blend ratios and a Pd(hfa)2 concentration.

  8. Improvement of Surface Wettability and Hydrophilization of Poly-paraphenylene benzobisoxazole Fiber with Fibrillation Combined Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Xiwen Wang

    2012-01-01

    Full Text Available A new surface modification method fibrillation combined with oxygen plasma treatment to improve the wettability and hydrophily of PBO fiber was studied in this paper. The surface chemical structure and morphology of PBO fiber were characterized by the methods of FTIR, XPS and SEM. The wettability and hydrophlic characters changes on the surface were evaluated by the dynamic contact angle system and image analysis. The results show that the increase surface roughness by fibrillation could improve the wettability. Fibrillation combined oxygen plasma treatment has a better effect than oxygen plasma treatment to improve the wettability and hdyrophlization of PBO fiber. The specific area of PBO fiber increased to 10.7 m2/g from 0.7 m2/g, contact angle decreased to 43.2° from 84.4° and WRV increased to 208.4% from 13.7%. The modified fibers have a good dispersion in water for hydrophilization improvement.

  9. Surface Hydrophilicity of Poly(l-Lactide Acid Polymer Film Changes the Human Adult Adipose Stem Cell Architecture

    Directory of Open Access Journals (Sweden)

    Chiara Argentati

    2018-02-01

    Full Text Available Current knowledge indicates that the molecular cross-talk between stem cells and biomaterials guides the stem cells’ fate within a tissue engineering system. In this work, we have explored the effects of the interaction between the poly(l-lactide acid (PLLA polymer film and human adult adipose stem cells (hASCs, focusing on the events correlating the materials’ surface characteristics and the cells’ plasma membrane. hASCs were seeded on films of pristine PLLA polymer and on a PLLA surface modified by the radiofrequency plasma method under oxygen flow (PLLA+O2. Comparative experiments were performed using human bone-marrow mesenchymal stem cells (hBM-MSCs and human umbilical matrix stem cells (hUCMSCs. After treatment with oxygen-plasma, the surface of PLLA films became hydrophilic, whereas the bulk properties were not affected. hASCs cultured on pristine PLLA polymer films acquired a spheroid conformation. On the contrary, hASCs seeded on PLLA+O2 film surface maintained the fibroblast-like morphology typically observed on tissue culture polystyrene. This suggests that the surface hydrophilicity is involved in the acquisition of the spheroid conformation. Noteworthy, the oxygen treatment had no effects on hBM-MSC and hUCMSC cultures and both stem cells maintained the same shape observed on PLLA films. This different behavior suggests that the biomaterial-interaction is stem cell specific.

  10. Surface hydrophilic modification of acrylonitrile-butadiene-styrene terpolymer by poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate): Preparation, characterization, and properties studies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Tingting; Zhang, Jun, E-mail: zhangjun@njtech.edu.cn

    2016-12-01

    Highlights: • Surface hydrophilic modified ABS was prepared by melt blending with PETG. • O= C−O groups were enriched on the surface with increasing PETG content. • Hydrophilic property of the blends was enhanced with increasing PETG content. • Phase inversion behavior of the blends occurred around intermediate composition. • Tensile and flexural strength were enhanced with increasing PETG content. - Abstract: Surface hydrophilic modified acrylonitrile-butadiene-styrene (ABS) terpolymer was prepared by melt blending with poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) random copolymer as the modifier. Attenuated total reflectance-Fourier transform-infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) were used for surface analysis. Through the contact angle measurement, the relationship between surface properties of the ABS/PETG blends and PETG content was investigated. Scanning electron microscope (SEM) and dynamical mechanical thermal analysis (DMTA) were used to characterize interface morphology and compatibility of the blends. The effect of PETG content on the mechanical and rheological properties was examined. The ATR-FTIR and XPS analysis suggested that the hydrophilic groups were enriched on the surface with increasing PETG content in the blend. The decrease of the water contact angle and the increase of the polarity for the blends with increasing PETG content indicated that the hydrophilic property of the blends was enhanced with increasing PETG content. The ABS/PETG blends were partially miscible. And the blends with ≤50 wt% PETG had better compatibility than the blends with above 50 wt% PETG. It was clear that below 50 wt% PETG, the PETG phase was dispersed in spherical form and the ABS phase was continuous. Above 50 wt% PETG, the PETG phase became continuous and the ABS phase was dispersed in irregular form. Moreover, the tensile strength and flexural strength of the blends were enhanced with

  11. A Simple Hydrophilic Treatment of SU-8 Surfaces for Cell Culturing and Cell Patterning

    DEFF Research Database (Denmark)

    Wang, Zhenyu; Stangegaard, Michael; Dufva, Hans Martin

    2005-01-01

    SU-8, an epoxy-based photoresist, widely used in constitution different mTAS systems, is incompatible with mammalian cell adhesion and culture in its native form. Here, we demonstrate a simple, cheap and robust two-step method to render a SU-8 surface hydrophilic and compatible with cell culture........ The contact angle of SU-8 surface was significantly reduced from 90° to 25° after the surface modification. The treated SU-8 surfaces provided a cell culture environment that was comparable with cell culture flask surface in terms of generation time and morphology....

  12. Negative-ion beam surface modification of tissue-culture polystyrene dishes for changing hydrophilic and cell-attachment properties

    International Nuclear Information System (INIS)

    Tsuji, H.; Satoh, H.; Ikeda, S.; Ikemura, S.; Gotoh, Y.; Ishikawa, J.

    1999-01-01

    Negative-silver-ion implantation into tissue-culture polystyrene (TCPS) dishes was investigated and it was found to modify hydrophilic and cell attachment properties of the dishes. Negative-ion implantation has an advantage of being almost free of surface charging, and is a suitable method for implantation into insulators such as polymers. Negative silver ions are used due to the antibacterial property of silver. Ag-implanted TCPS dishes had a contact angle larger than the normal value of 66 deg. of unimplanted dishes. The contact angle of water had a strong dependence on the ion energy rather than the dose. As a cell-culture experiment, human umbilical vascular endothelial cell (HUVEC) was used in unimplanted and Ag-implanted TCPS dishes, the implantation removed the cell-attachment property of the surface. In implantation with a mask with a striped pattern, most attached cells of HUVEC were in the unimplanted region aligned along a stripe direction

  13. Effect of Graphene Oxide (GO) on the Surface Morphology & Hydrophilicity of Polyethersulfone (PES)

    Science.gov (United States)

    Junaidi, N. F. D.; Khalil, N. A.; Jahari, A. F.; Shaari, N. Z. K.; Shahruddin, M. Z.; Alias, N. H.; Othman, N. H.

    2018-05-01

    Membrane has been widely used in water and wastewater treatment. One of the major issues related membrane separation is concentration polarization or fouling, which can lead to a decline of flux and premature failure of membrane. However, fouling can be controlled by modification of membrane properties such as morphology and hydrophilicity. In this work, a modification of polymeric membrane, polyethersulfone (PES) was carried out using graphene oxide in order to attain high antifouling characteristics. Graphene oxide (GO) was added at different compositions ranging from (0.1 wt%-1.0 wt%). GO was synthesized using modified Hummers’ method and characterized using XRD and FTIR prior to using it as additive for the PES membrane. The prepared PES-GO composite membranes were characterized using FTIR and SEM, Contact angle measurement and pure water flux test were then conducted to investigate the hydrophilicity of the PES-GO membranes. It was found that the additions of GO has significantly improved the hydrophilicity of the membranes.

  14. Mechanically durable underwater superoleophobic surfaces based on hydrophilic bulk metals for oil/water separation

    Science.gov (United States)

    Yu, Huadong; Lian, Zhongxu; Xu, Jinkai; Wan, Yanling; Wang, Zuobin; Li, Yiquan; Yu, Zhanjiang; Weng, Zhankun

    2018-04-01

    Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

  15. Anisotropic wetting characteristics versus roughness on machined surfaces of hydrophilic and hydrophobic materials

    International Nuclear Information System (INIS)

    Liang, Yande; Shu, Liming; Natsu, Wataru; He, Fuben

    2015-01-01

    Graphical abstract: - Highlights: • The aim is to investigate the influence of roughness on anisotropic wetting on machined surfaces. • The relationship between roughness and anisotropic wetting is modeled by thermodynamical analysis. • The effect of roughness on anisotropic wetting on hydrophilic materials is stronger than that on hydrophobic materials. • The energy barrier existing in the direction perpendicular to the lay is one of the main reasons for the anisotropic wetting. • The contact angle in the parallel direction is larger than that in the perpendicular direction. - Abstract: Anisotropic wetting of machined surfaces is widely applied in industries which can be greatly affected by roughness and solid's chemical properties. However, there has not been much work on it. A free-energy thermodynamic model is presented by analyzing geometry morphology of machined surfaces (2-D model surfaces), which demonstrates the influence of roughness on anisotropic wetting. It can be concluded that the energy barrier is one of the main reasons for the anisotropic wetting existing in the direction perpendicular to the lay. In addition, experiments in investigating anisotropic wetting, which was characterized by the static contact angle and droplet's distortion, were performed on machined surfaces with different roughness on hydrophilic and hydrophobic materials. The droplet's anisotropy found on machined surfaces increased with mean slope of roughness profile Kr. It indicates that roughness on anisotropic wetting on hydrophilic materials has a stronger effect than that on hydrophobic materials. Furthermore, the contact angles predicted by the model are basically consistent with the experimentally ones

  16. Hydrophilization of poly(ether ether ketone) films by surface-initiated atom transfer radical polymerization

    DEFF Research Database (Denmark)

    Fristrup, Charlotte Juel; Jankova Atanasova, Katja; Hvilsted, Søren

    2010-01-01

    Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) has been exploited to hydrophilize PEEK. The ketone groups on the PEEK surface were reduced to hydroxyl groups which were converted to bromoisobutyrate initiating sites for SI-ATRP. The modification steps were followed by contact...... angle measurements and XPS. Moreover, ATR FTIR has been used to confirm the formation of initiating groups. Grafting of PEGMA from PEEK was performed in aqueous solution. The presence of the PPEGMA grafts on PEEK was revealed by the thermograms from TGA whereas investigations with AFM rejected changes...

  17. Temporal Changes in Extracellular Polymeric Substances on Hydrophobic and Hydrophilic Membrane Surfaces in a Submerged Membrane Bioreactor

    KAUST Repository

    Matar, Gerald; Gonzalez-Gil, Graciela; Maab, Husnul; Nunes, Suzana Pereira; Le-Clech, Pierre; Vrouwenvelder, Johannes S.; Saikaly, Pascal

    2016-01-01

    multidimensional scaling of LC-OCD data showed that biofilm samples clustered according to the sampling event (time) regardless of the membrane surface chemistry (hydrophobic or hydrophilic) or operating mode (with or without permeate flux). These results suggest

  18. Synthesis of Environmentally Responsive Polymers by Atom Transfer Radical Polymerization: Generation of Reversible Hydrophilic and Hydrophobic Surfaces

    Directory of Open Access Journals (Sweden)

    Vikas Mittal

    2010-05-01

    Full Text Available Environmentally responsive poly(N-isopropylacrylamide brushes were grafted from the surface of polymer particles or flat surfaces in order to generate reversible hydrophilic and hydrophobic surfaces. The use of atom transfer radical polymerization was demonstrated for the grafting of polymer brushes as it allows efficient control on the amount of grafted polymer. The polymer particles were generated with or without surfactant in the emulsion polymerization and their surface could be modified with the atom transfer radical polymerization (ATRP initiator. The uniform functionalization of the surface with ATRP initiator was responsible for the uniform grafting of polymer brushes. The grafted brushes responded reversibly with changes in temperature indicating that the reversible responsive behavior could be translated to the particle surfaces. The particles were observed to adsorb and desorb protein and virus molecules by changing the temperatures below or higher than 32 °C. The initiator functionalized particles could also be adsorbed on the flat surfaces. The adsorption process also required optimization of the heat treatment conditions to form a uniform layer of the particles on the substrate. The grafted polymer brushes also responded to the changes in temperatures similar to the spherical particles studied through water droplets placed on the flat substrates.

  19. Effects of hydrophilicity and microtopography of titanium implant surfaces on initial supragingival plaque biofilm formation. A pilot study.

    Science.gov (United States)

    Schwarz, F; Sculean, A; Wieland, M; Horn, N; Nuesry, E; Bube, C; Becker, J

    2007-12-01

    The aim of the present pilot study is to investigate the effects of hydrophilicity and microtopography of titanium implant surfaces on initial supragingival plaque biofilm formation. Test specimens were manufactured from commercially pure grade 2 titanium according to one of the following procedures: polished (P), acid-etched (A), chemically modified (mod) A (modA), sand-blasted large grit and A (SLA), and modSLA. Intraoral splints were used to collect an in vivo supragingival plaque biofilm in each group at 12, 24, and 48 h. Stained plaque biofilm (PB) areas (%) were morphometrically assessed. All groups exhibited significant increases of mean PB areas over time (p P > A =modA (p modSLA = P > A = modA (p A = modA (p < 0.001; respectively). Within the limits of a pilot study, it could be concluded that hydrophilicity had no apparent effect, while microtopography had a highly uneven and unpredictable influence on supragingival plaque biofilm formation.

  20. Effect of heat treatment on surface hydrophilicity-retaining ability of titanium dioxide nanotubes

    Science.gov (United States)

    Sun, Yu; Sun, Shupei; Liao, Xiaoming; Wen, Jiang; Yin, Guangfu; Pu, Ximing; Yao, Yadong; Huang, Zhongbing

    2018-05-01

    The aim of this study is to investigate the effect of different annealing temperature and atmosphere on the surface wettability retaining properties of titania nanotubes (TNs) fabricated by anodization. The TNs morphology, crystal phase composition and surface elemental composition and water contact angle (WCA) were investigated by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and contact angle instrument, respectively. After the samples annealed at 200 °C, 450 °C, 850 °C have been stored in air for 28 days, the WCAs increase to 31.7°, 21.1° and 110.5°, respectively. The results indicate that crystal phase composition of TNs plays an important role in surface wettability. Compared with the WCA (21.1°) of the samples annealed in air after 28 days, the WCA of samples annealed in oxygen-deficient atmosphere is lower, suggesting the contribution of oxygen vacancy in the enhanced hydrophilicity-retaining ability. Our study demonstrates that the surface hydrophilicity-retaining ability of TNs is related to the ordered nanotubular structure, crystal structure, the amount of surface hydroxyl group and oxygen vacancy defects.

  1. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    International Nuclear Information System (INIS)

    Kucinska-Lipka, J.; Gubanska, I.; Strankowski, M.; Cieśliński, H.; Filipowicz, N.; Janik, H.

    2017-01-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with

  2. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kucinska-Lipka, J., E-mail: juskucin@pg.gda.pl [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Gubanska, I.; Strankowski, M. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Cieśliński, H.; Filipowicz, N. [Gdansk University of Technology, Faculty of Chemistry, Department of Microbiology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Janik, H. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland)

    2017-06-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ({sup 1}HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-30

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

  4. Exploring the Leishmania Hydrophilic Acylated Surface Protein B (HASPB) Export Pathway by Live Cell Imaging Methods.

    Science.gov (United States)

    MacLean, Lorna; Price, Helen; O'Toole, Peter

    2016-01-01

    Leishmania major is a human-infective protozoan parasite transmitted by the bite of the female phlebotomine sand fly. The L. major hydrophilic acylated surface protein B (HASPB) is only expressed in infective parasite stages suggesting a role in parasite virulence. HASPB is a "nonclassically" secreted protein that lacks a conventional signal peptide, reaching the cell surface by an alternative route to the classical ER-Golgi pathway. Instead HASPB trafficking to and exposure on the parasite plasma membrane requires dual N-terminal acylation. Here, we use live cell imaging methods to further explore this pathway allowing visualization of key events in real time at the individual cell level. These methods include live cell imaging using fluorescent reporters to determine the subcellular localization of wild type and acylation site mutation HASPB18-GFP fusion proteins, fluorescence recovery after photobleaching (FRAP) to analyze the dynamics of HASPB in live cells, and live antibody staining to detect surface exposure of HASPB by confocal microscopy.

  5. Hydrophilic crosslinked-polymeric surface capable of effective suppression of protein adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kamon, Yuri; Inoue, Naoko; Mihara, Erika; Kitayama, Yukiya; Ooya, Tooru; Takeuchi, Toshifumi, E-mail: takeuchi@gold.kobe-u.ac.jp

    2016-08-15

    Highlights: • Three hydrophilic crosslinked polymers were examined for protein adsorption. • All polymers showed low nonspecific adsorption of negatively charged proteins. • Poly(MMPC) showed the lowest adsorption for positively charged proteins. • Poly(MMPC) is able to reduce nonspecific adsorption of a wide range of proteins. - Abstract: We investigated the nonspecific adsorption of proteins towards three hydrophilic crosslinked-polymeric thin layers prepared by surface-initiated atom transfer radical polymerization using N,N′-methylenebisacrylamide, 2-(methacryloyloxy)ethyl-[N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC), or 6,6′-diacryloyl-trehalose crosslinkers. Protein binding experiments were performed by surface plasmon resonance with six proteins of different pI values including α-lactalbumin, bovine serum albumin (BSA), myoglobin, ribonuclease A, cytochrome C, and lysozyme in buffer solution at pH 7.4. All of the obtained crosslinked-polymeric thin layers showed low nonspecific adsorption of negatively charged proteins at pH 7.4 such as α-lactalbumin, BSA, and myoglobin. Nonspecific adsorption of positively charged proteins including ribonuclease A, cytochrome C, and lysozyme was the lowest for poly(MMPC). These results suggest poly(MMPC) can effectively reduce nonspecific adsorption of a wide range of proteins that are negatively or positively charged at pH 7.4. MMPC is a promising crosslinker for a wide range of polymeric materials requiring low nonspecific protein binding.

  6. Environmentally responsive surface-modified silica nanoparticles for enhanced oil recovery

    International Nuclear Information System (INIS)

    Behzadi, Abed; Mohammadi, Aliasghar

    2016-01-01

    Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at various quantities, and their ability to modulate oil–water interface properties and oil recovery is examined. Oil–water interfacial tension and water surface tension are decreased by 50 % in the presence of silica nanoparticles coated with both agents. Measuring oil-drop contact angle on oil-wetted glass slides and carbonate rock sections, after aging in various surface-modified silica nanofluids, indicates that the wettability of various oil-wetted surfaces is modified from strongly oil-wet to water-wet. Flooding nanofluids to glass micro-models and pore-level investigations demonstrate that surface modification of silica nanoparticles, specially, with both hydrophilic and hydrophobic agents improves considerably their performance in increasing oil recovery and wettability alteration.

  7. Environmentally responsive surface-modified silica nanoparticles for enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Behzadi, Abed; Mohammadi, Aliasghar, E-mail: amohammadi@sharif.edu [Sharif University of Technology, Department of Chemical and Petroleum Engineering (Iran, Islamic Republic of)

    2016-09-15

    Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at various quantities, and their ability to modulate oil–water interface properties and oil recovery is examined. Oil–water interfacial tension and water surface tension are decreased by 50 % in the presence of silica nanoparticles coated with both agents. Measuring oil-drop contact angle on oil-wetted glass slides and carbonate rock sections, after aging in various surface-modified silica nanofluids, indicates that the wettability of various oil-wetted surfaces is modified from strongly oil-wet to water-wet. Flooding nanofluids to glass micro-models and pore-level investigations demonstrate that surface modification of silica nanoparticles, specially, with both hydrophilic and hydrophobic agents improves considerably their performance in increasing oil recovery and wettability alteration.

  8. [Preparation of cysteine-click maltose modified silica as a hydrophilic interaction liquid chromatography material for the enrichment of glycopeptides].

    Science.gov (United States)

    Sun, Xudong; Zhang, Lingyi; Zhang, Weibing

    2017-07-08

    Because of the low abundance of glycoprotein and glycopeptide in complex biological samples, it is urgent to develop an efficient method for glycopeptide enrichment in comprehensive and in-depth glycoproteomes research. Herein, a novel hydrophilic silica was developed through surface modification with cysteine-click maltose (Cys-Mal@SiO 2 ). The developed hydrophilic silica was packed into a solid phase extraction (SPE) column, and applied to the highly selective enrichment and identification of N -linked glycopeptides. The Cys-Mal@SiO 2 demonstrated better identification capability over Cys@SiO 2 , Mal@SiO 2 and commercial hydrophilic interaction liquid chromatography (HILIC) in glycopeptide enrichment due to the synergistic effect of the two kinds of hydrophilic molecules. In the selective enrichment of tryptic digest from human immunoglobulin G, glycopeptides with higher signal-to-noises were detected by Cys-Mal@SiO 2 . In addition, 1551 unique glycopeptides with 906 N -glycosylation sites from 466 different N -linked glycoproteins were identified from the proteins extracted from mouse liver after the enrichment with Cys-Mal@SiO 2 . In contrast, the numbers of identified glycopeptides, glycoproteins and N -glycosylation sites identified by Cys@SiO 2 were 211, 67, 127 respectively less than by Cys-Mal@SiO 2 , and the corresponding numbers were 289, 76, 193 by Mal@SiO 2 . These results showed that the developed Cys-Mal@SiO 2 is a promising affinity material for N -glycoproteomics research of real complex biological samples.

  9. Highly Hydrophilic Polyvinylidene Fluoride (PVDF) Ultrafiltration Membranes via Postfabrication Grafting of Surface-Tailored Silica Nanoparticles

    KAUST Repository

    Liang, Shuai

    2013-07-24

    Polyvinylidene fluoride (PVDF) has drawn much attention as a predominant ultrafiltration (UF) membrane material due to its outstanding mechanical and physicochemical properties. However, current applications suffer from the low fouling resistance of the PVDF membrane due to the intrinsic hydrophobic property of the membrane. The present study demonstrates a novel approach for the fabrication of a highly hydrophilic PVDF UF membrane via postfabrication tethering of superhydrophilic silica nanoparticles (NPs) to the membrane surface. The pristine PVDF membrane was grafted with poly(methacrylic acid) (PMAA) by plasma induced graft copolymerization, providing sufficient carboxyl groups as anchor sites for the binding of silica NPs, which were surface-tailored with amine-terminated cationic ligands. The NP binding was achieved through a remarkably simple and effective dip-coating technique in the presence or absence of the N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) cross-linking process. The properties of the membrane prepared from the modification without EDC/NHS cross-linking were comparable to those for the membrane prepared with the EDC/NHS cross-linking. Both modifications almost doubled the surface energy of the functionalized membranes, which significantly improved the wettability of the membrane and converted the membrane surface from hydrophobic to highly hydrophilic. The irreversibly bound layer of superhydrophilic silica NPs endowed the membranes with strong antifouling performance as demonstrated by three sequential fouling filtration runs using bovine serum albumin (BSA) as a model organic foulant. The results suggest promising applications of the postfabrication surface modification technique in various membrane separation areas. © 2013 American Chemical Society.

  10. Switchable Super-Hydrophilic/Hydrophobic Indium Tin Oxide (ITO) Film Surfaces on Reactive Ion Etching (RIE) Textured Si Wafer.

    Science.gov (United States)

    Kim, Hwa-Min; Litao, Yao; Kim, Bonghwan

    2015-11-01

    We have developed a surface texturing process for pyramidal surface features along with an indium tin oxide (ITO) coating process to fabricate super-hydrophilic conductive surfaces. The contact angle of a water droplet was less than 5 degrees, which means that an extremely high wettability is achievable on super-hydrophilic surfaces. We have also fabricated a super-hydrophobic conductive surface using an additional coating of polytetrafluoroethylene (PTFE) on the ITO layer coated on the textured Si surface; the ITO and PTFE films were deposited by using a conventional sputtering method. We found that a super-hydrophilic conductive surface is produced by ITO coated on the pyramidal Si surface (ITO/Si), with contact angles of approximately 0 degrees and a resistivity of 3 x 10(-4) Ω x cm. These values are highly dependent on the substrate temperature during the sputtering process. We also found that the super-hydrophobic conductive surface produced by the additional coating of PTFE on the pyramidal Si surface with an ITO layer (PTFE/ITO/Si) has a contact angle of almost 160 degrees and a resistivity of 3 x 10(-4) Ω x cm, with a reflectance lower than 9%. Therefore, these processes can be used to fabricate multifunctional features of ITO films for switchable super-hydrophilic and super-hydrophobic surfaces.

  11. Development of a classical force field for the oxidized Si surface: application to hydrophilic wafer bonding.

    Science.gov (United States)

    Cole, Daniel J; Payne, Mike C; Csányi, Gábor; Spearing, S Mark; Colombi Ciacchi, Lucio

    2007-11-28

    We have developed a classical two- and three-body interaction potential to simulate the hydroxylated, natively oxidized Si surface in contact with water solutions, based on the combination and extension of the Stillinger-Weber potential and of a potential originally developed to simulate SiO(2) polymorphs. The potential parameters are chosen to reproduce the structure, charge distribution, tensile surface stress, and interactions with single water molecules of a natively oxidized Si surface model previously obtained by means of accurate density functional theory simulations. We have applied the potential to the case of hydrophilic silicon wafer bonding at room temperature, revealing maximum room temperature work of adhesion values for natively oxidized and amorphous silica surfaces of 97 and 90 mJm(2), respectively, at a water adsorption coverage of approximately 1 ML. The difference arises from the stronger interaction of the natively oxidized surface with liquid water, resulting in a higher heat of immersion (203 vs 166 mJm(2)), and may be explained in terms of the more pronounced water structuring close to the surface in alternating layers of larger and smaller densities with respect to the liquid bulk. The computed force-displacement bonding curves may be a useful input for cohesive zone models where both the topographic details of the surfaces and the dependence of the attractive force on the initial surface separation and wetting can be taken into account.

  12. Structural and dynamical properties of water confined between two hydrophilic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Di Napoli, Solange, E-mail: dinapoli@tandar.cnea.gov.a [Depto. de Fisica - CAC, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Gamba, Zulema, E-mail: gamba@tandar.cnea.gov.a [Depto. de Fisica - CAC, Comision Nacional de Energia Atomica, Av. Gral Paz 1499, (1650) San Martin, Buenos Aires (Argentina)

    2009-10-01

    The properties of water in the vicinity of surfaces and under confinement have been extensively studied because of the relevance of a quantitative understanding of many processes that not only take place in biological systems, like cells, membranes and microemulsions, but also in many others such as confined water in rocks, ionic channels and interestellar matter. In this work we perform molecular dynamic calculations of the nanoscopic structure of TIP5P model water confined between two hydrophilic surfaces. We calculate the diffusion coefficients and the atomic density profile of water molecules and polar ions in the system as a function of the number of water molecules per amphiphilic (n{sub W}). We also study the dependence of the water layer thickness and the profiles of water dipole orientation with this parameter.

  13. Structural and dynamical properties of water confined between two hydrophilic surfaces

    International Nuclear Information System (INIS)

    Di Napoli, Solange; Gamba, Zulema

    2009-01-01

    The properties of water in the vicinity of surfaces and under confinement have been extensively studied because of the relevance of a quantitative understanding of many processes that not only take place in biological systems, like cells, membranes and microemulsions, but also in many others such as confined water in rocks, ionic channels and interestellar matter. In this work we perform molecular dynamic calculations of the nanoscopic structure of TIP5P model water confined between two hydrophilic surfaces. We calculate the diffusion coefficients and the atomic density profile of water molecules and polar ions in the system as a function of the number of water molecules per amphiphilic (n W ). We also study the dependence of the water layer thickness and the profiles of water dipole orientation with this parameter.

  14. Transport mechanism of an initially spherical droplet on a combined hydrophilic/hydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Myong, Hyon Kook; Kwon, Young Hoo [Dept. of Mechanical Engineering, Kookmin University, Seoul (Korea, Republic of)

    2015-11-15

    Fluid transport is a key issue in the development of microfluidic systems. Recently, Myong (2014) has proposed a new concept for droplet transport without external power sources, and numerically validated the results for a hypothetical 2D shape, initially having a hemicylindrical droplet shape. Myong and Kwon (2015) have also examined the transport mechanism for an actual water droplet, initially having a 3D hemispherical shape, on a horizontal hydrophilic/hydrophobic surface, based on the numerical results of the time evolution of the droplet shape, as well as the total kinetic, gravitational, pressure and surface free energies inside the droplet. In this study, a 3D numerical analysis of an initially spherical droplet is carried out to establish a new concept for droplet transport. Further, the transport mechanism of an actual water droplet is examined in detail from the viewpoint of the capillarity force imbalance through the numerical results of droplet shape and various energies inside the droplet.

  15. A New Concept to Transport a Droplet on Horizontal Hydrophilic/Hydrophobic Surfaces

    International Nuclear Information System (INIS)

    Myong, Hyon Kook

    2014-01-01

    A fluid transport technique is a key issue for the development of microfluidic systems. In this paper, a new concept for transporting a droplet without external power sources is proposed and verified numerically. The proposed device is a heterogeneous surface which has both hydrophilic and hydrophobic horizontal surfaces. The numerical simulation to demonstrate the new concept is conducted by an in-house solution code (PowerCFD) which employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with interface capturing method (CICSAM) in a volume of fluid (VOF) scheme for phase interface capturing. It is found that the proposed concept for droplet transport shows superior performance for droplet transport in microfluidic systems

  16. Highly Hydrophilic Thin-Film Composite Forward Osmosis Membranes Functionalized with Surface-Tailored Nanoparticles

    KAUST Repository

    Tiraferri, Alberto

    2012-09-26

    Thin-film composite polyamide membranes are state-of-the-art materials for membrane-based water purification and desalination processes, which require both high rejection of contaminants and high water permeabilities. However, these membranes are prone to fouling when processing natural waters and wastewaters, because of the inherent surface physicochemical properties of polyamides. The present work demonstrates the fabrication of forward osmosis polyamide membranes with optimized surface properties via facile and scalable functionalization with fine-tuned nanoparticles. Silica nanoparticles are coated with superhydrophilic ligands possessing functional groups that impart stability to the nanoparticles and bind irreversibly to the native carboxyl moieties on the membrane selective layer. The tightly tethered layer of nanoparticles tailors the surface chemistry of the novel composite membrane without altering the morphology or water/solute permeabilities of the membrane selective layer. Surface characterization and interfacial energy analysis confirm that highly hydrophilic and wettable membrane surfaces are successfully attained. Lower intermolecular adhesion forces are measured between the new membrane materials and model organic foulants, indicating the presence of a bound hydration layer at the polyamide membrane surface that creates a barrier for foulant adhesion. © 2012 American Chemical Society.

  17. Hydrophilic Graphene Preparation from Gallic Acid Modified Graphene Oxide in Magnesium Self-Propagating High Temperature Synthesis Process

    Science.gov (United States)

    Cao, Lei; Li, Zhenhuan; Su, Kunmei; Cheng, Bowen

    2016-10-01

    Hydrophilic graphene sheets were synthesized from a mixture of magnesium and gallic acid (GA) modified graphene oxide (GO) in a self-propagating high-temperature synthesis (SHS) process, and hydrophilic graphene sheets displayed the higher C/O ratio (16.36), outstanding conductivity (~88900 S/m) and excellent water-solubility. GO sheets were connected together by GA, and GA was captured to darn GO structure defects through the formation of hydrogen bonds and ester bonds. In SHS process, the most oxygen ions of GO reacted with magnesium to prevent the escape of carbon dioxide and carbon monoxide to from the structure defects associated with vacancies, and GA could take place the high-temperature carbonization, during which a large-area graphene sheets formed with a part of the structure defects being repaired. When only GO was reduced by magnesium in SHS process, and the reduced GO (rGO) exhibited the smaller sheets, the lower C/O ratio (15.26), the weaker conductivity (4200 S/m) and the poor water-solubility because rGO inevitably left behind carbon vacancies and topological defects. Therefore, the larger sheet, less edge defects and free structure defects associated with vacancies play a key role for graphene sheets good dispersion in water.

  18. 3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

    Science.gov (United States)

    Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

    2016-04-01

    Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

  19. Visual function after implantation of single-piece toric hydrophilic acrylic intraocular lenses with hydrophobic surface six months after cataract surgery

    Directory of Open Access Journals (Sweden)

    Alja Črnej

    2012-06-01

    Conclusion: Patients with medium to high corneal astigmatism and implanted single-piece toric hydrophilic acrylic IOLs with hydrophobic surface have very good visual function six months postoperatively.

  20. Synthesis and characterization of nanocomposites based on polyurethane in aqueous dispersions with non-modified hydrophilic clays

    International Nuclear Information System (INIS)

    Miranda, G.S.; Delpechi, M.C.; Santo, W.L.E.

    2010-01-01

    Several studies involving the formation of polyurethane nanocomposites employing clays of montmorillonite modified. This involves the presence of quaternary ammonium salts, the cation exchange needed to increase the interlayer space of clays that incorporate more than one step to the process, generates a higher cost. In this paper the synthesis of nanocomposite polyurethanes dispersed in water allowed not only the production of materials less harmful to the environment, but also the incorporation of hydrophilic clays, calcium and sodium in nature, without any modifications. Dispersions produced from 0.5, 1.0 and 2.5% clay (on the mass of prepolymer) were characterized in terms of total solids content, the films obtained by casting were evaluated for adhesiveness, diffraction X-rays, scanning electron microscopy. Most systems showed intercalated and partially exfoliated structures. (author)

  1. Wetting, adhesion and friction of superhydrophobic and hydrophilic leaves and fabricated micro/nanopatterned surfaces

    Science.gov (United States)

    Bhushan, Bharat; Jung, Yong Chae

    2008-06-01

    Superhydrophobic surfaces have considerable technological potential for various applications due to their extreme water-repellent properties. When two hydrophilic bodies are brought into contact, any liquid present at the interface forms menisci, which increases adhesion/friction and the magnitude is dependent upon the contact angle. Certain plant leaves are known to be superhydrophobic in nature due to their roughness and the presence of a thin wax film on the leaf surface. Various leaf surfaces on the microscale and nanoscale have been characterized in order to separate out the effects of the microbumps and nanobumps and the wax on the hydrophobicity. The next logical step in realizing superhydrophobic surfaces that can be produced is to design surfaces based on understanding of the leaves. The effect of micropatterning and nanopatterning on the hydrophobicity was investigated for two different polymers with micropatterns and nanopatterns. Scale dependence on adhesion was also studied using atomic force microscope tips of various radii. Studies on silicon surfaces patterned with pillars of varying diameter, height and pitch values and deposited with a hydrophobic coating were performed to demonstrate how the contact angles vary with the pitch. The effect of droplet size on contact angle was studied by droplet evaporation and a transition criterion was developed to predict when air pockets cease to exist. Finally, an environmental scanning electron microscope study on the effect of droplet size of about 20 µm radius on the contact angle of patterned surfaces is presented. The importance of hierarchical roughness structure on destabilization of air pockets is discussed.

  2. Numerical Simulation of Turbulent Half-corrugated Channel Flow by Hydrophilic and Hydrophobic Surfaces

    Directory of Open Access Journals (Sweden)

    M. R. Rastan

    2018-03-01

    Full Text Available In the first part of the present study, a two dimensional half-corrugated channel flow is simulated at Reynolds number of 104, in no-slip condition (hydrophilic surfaces( using various low Reynolds turbulence models as well as standard k-ε model; and an appropriate turbulence model (k-ω 1998 model( is proposed. Then, in order to evaluate the proposed solution method in simulation of flow adjacent to hydrophobic surfaces, turbulent flow is simulated in simple channel and the results are compared with the literature. Finally, two dimensional half-corrugated channel flow at Reynolds number of 104 is simulated again in vicinity of hydrophobic surfaces for varoius slip lengths. The results show that this method is capable of drag reduction in such a way that an increase of 200 μm in slip length leads to a massive drag reduction up to 38%. In addition, to access a significant drag reduction in turbulent flows, the non-dimensionalized slip length should be larger than the minimum.

  3. Interactions between nano-TiO{sub 2} and the oral cavity: Impact of nanomaterial surface hydrophilicity/hydrophobicity

    Energy Technology Data Exchange (ETDEWEB)

    Teubl, Birgit J.; Schimpel, Christa [Institute of Pharmaceutical Sciences, Department of Pharmaceutical Technology, University of Graz, 8010 (Austria); Leitinger, Gerd [Institute of Cell Biology, Histology and Embryology, Research Unit Electron Microscopic Techniques, Medical University of Graz, 8010 (Austria); Center for Medical Research, Medical University of Graz, 8010 (Austria); BioTechMed, Graz 8010 (Austria); Bauer, Bettina [Institute of Pharmaceutical Sciences, Department of Pharmaceutical Technology, University of Graz, 8010 (Austria); Fröhlich, Eleonore [Center for Medical Research, Medical University of Graz, 8010 (Austria); BioTechMed, Graz 8010 (Austria); Zimmer, Andreas [Institute of Pharmaceutical Sciences, Department of Pharmaceutical Technology, University of Graz, 8010 (Austria); BioTechMed, Graz 8010 (Austria); Roblegg, Eva, E-mail: eva.roblegg@uni-graz.at [Institute of Pharmaceutical Sciences, Department of Pharmaceutical Technology, University of Graz, 8010 (Austria); BioTechMed, Graz 8010 (Austria)

    2015-04-09

    Highlights: • Hydrophilic as well as hydrophobic TiO{sub 2} NPs agglomerated under oral physiological conditions. • Particles penetrated the upper and lower buccal epithelium, independent on the degree of hydrophilicity. • Most of the hydrophobic particles were found in vesicular structures, while hydrophilic particles were freely distributed in the cytoplasm. • Hydrophilic particles had a higher potential to trigger toxic effects (e.g., ROS) than hydrophobic particles. - Abstract: Titanium dioxide (TiO{sub 2}) nanoparticles are available in a variety of oral applications, such as food additives and cosmetic products. Thus, questions about their potential impact on the oro-gastrointestinal route rise. The oral cavity represents the first portal of entry and is known to rapidly interact with nanoparticles. Surface charge and size contribute actively to the particle–cell interactions, but the influence of surface hydrophilicity/hydrophobicity has never been shown before. This study addresses the biological impact of hydrophilic (NM 103, rutile, 20 nm) and hydrophobic (NM 104, rutile, 20 nm) TiO{sub 2} particles within the buccal mucosa. Particle characterization was addressed with dynamic light scattering and laser diffraction. Despite a high agglomeration tendency, 10% of the particles/agglomerates were present in the nanosized range and penetrated into the mucosa, independent of the surface properties. However, significant differences were observed in intracellular particle localization. NM 104 particles were found freely distributed in the cytoplasm, whereas their hydrophobic counterparts were engulfed in vesicular structures. Although cell viability/membrane integrity was not affected negatively, screening assays demonstrated that NM 104 particles showed a higher potential to decrease the physiological mitochondrial membrane potential than NM 103, resulting in a pronounced generation of reactive oxygen species.

  4. Interactions between nano-TiO2 and the oral cavity: Impact of nanomaterial surface hydrophilicity/hydrophobicity

    International Nuclear Information System (INIS)

    Teubl, Birgit J.; Schimpel, Christa; Leitinger, Gerd; Bauer, Bettina; Fröhlich, Eleonore; Zimmer, Andreas; Roblegg, Eva

    2015-01-01

    Highlights: • Hydrophilic as well as hydrophobic TiO 2 NPs agglomerated under oral physiological conditions. • Particles penetrated the upper and lower buccal epithelium, independent on the degree of hydrophilicity. • Most of the hydrophobic particles were found in vesicular structures, while hydrophilic particles were freely distributed in the cytoplasm. • Hydrophilic particles had a higher potential to trigger toxic effects (e.g., ROS) than hydrophobic particles. - Abstract: Titanium dioxide (TiO 2 ) nanoparticles are available in a variety of oral applications, such as food additives and cosmetic products. Thus, questions about their potential impact on the oro-gastrointestinal route rise. The oral cavity represents the first portal of entry and is known to rapidly interact with nanoparticles. Surface charge and size contribute actively to the particle–cell interactions, but the influence of surface hydrophilicity/hydrophobicity has never been shown before. This study addresses the biological impact of hydrophilic (NM 103, rutile, 20 nm) and hydrophobic (NM 104, rutile, 20 nm) TiO 2 particles within the buccal mucosa. Particle characterization was addressed with dynamic light scattering and laser diffraction. Despite a high agglomeration tendency, 10% of the particles/agglomerates were present in the nanosized range and penetrated into the mucosa, independent of the surface properties. However, significant differences were observed in intracellular particle localization. NM 104 particles were found freely distributed in the cytoplasm, whereas their hydrophobic counterparts were engulfed in vesicular structures. Although cell viability/membrane integrity was not affected negatively, screening assays demonstrated that NM 104 particles showed a higher potential to decrease the physiological mitochondrial membrane potential than NM 103, resulting in a pronounced generation of reactive oxygen species

  5. Hydrophilic property of 316L stainless steel after treatment by atmospheric pressure corona streamer plasma using surface-sensitive analyses

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hamarneh, Ibrahim, E-mail: hamarnehibrahim@yahoo.com [Department of Physics, Faculty of Science, Al-Balqa Applied University, Salt 19117 (Jordan); Pedrow, Patrick [School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164 (United States); Eskhan, Asma; Abu-Lail, Nehal [Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164 (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Surface hydrophilic property of surgical-grade 316L stainless steel was enhanced by Ar-O{sub 2} corona streamer plasma treatment. Black-Right-Pointing-Pointer Hydrophilicity, surface morphology, roughness, and chemical composition before and after plasma treatment were evaluated. Black-Right-Pointing-Pointer Contact angle measurements and surface-sensitive analyses techniques, including XPS and AFM, were carried out. Black-Right-Pointing-Pointer Optimum plasma treatment conditions of the SS 316L surface were determined. - Abstract: Surgical-grade 316L stainless steel (SS 316L) had its surface hydrophilic property enhanced by processing in a corona streamer plasma reactor using O{sub 2} gas mixed with Ar at atmospheric pressure. Reactor excitation was 60 Hz ac high-voltage (0-10 kV{sub RMS}) applied to a multi-needle-to-grounded screen electrode configuration. The treated surface was characterized with a contact angle tester. Surface free energy (SFE) for the treated stainless steel increased measurably compared to the untreated surface. The Ar-O{sub 2} plasma was more effective in enhancing the SFE than Ar-only plasma. Optimum conditions for the plasma treatment system used in this study were obtained. X-ray photoelectron spectroscopy (XPS) characterization of the chemical composition of the treated surfaces confirms the existence of new oxygen-containing functional groups contributing to the change in the hydrophilic nature of the surface. These new functional groups were generated by surface reactions caused by reactive oxidation of substrate species. Atomic force microscopy (AFM) images were generated to investigate morphological and roughness changes on the plasma treated surfaces. The aging effect in air after treatment was also studied.

  6. Surface modified electrospun nanofibrous scaffolds for nerve tissue engineering

    International Nuclear Information System (INIS)

    Prabhakaran, Molamma P; Venugopal, J; Chan, Casey K; Ramakrishna, S

    2008-01-01

    The development of biodegradable polymeric scaffolds with surface properties that dominate interactions between the material and biological environment is of great interest in biomedical applications. In this regard, poly-ε-caprolactone (PCL) nanofibrous scaffolds were fabricated by an electrospinning process and surface modified by a simple plasma treatment process for enhancing the Schwann cell adhesion, proliferation and interactions with nanofibers necessary for nerve tissue formation. The hydrophilicity of surface modified PCL nanofibrous scaffolds (p-PCL) was evaluated by contact angle and x-ray photoelectron spectroscopy studies. Naturally derived polymers such as collagen are frequently used for the fabrication of biocomposite PCL/collagen scaffolds, though the feasibility of procuring large amounts of natural materials for clinical applications remains a concern, along with their cost and mechanical stability. The proliferation of Schwann cells on p-PCL nanofibrous scaffolds showed a 17% increase in cell proliferation compared to those on PCL/collagen nanofibrous scaffolds after 8 days of cell culture. Schwann cells were found to attach and proliferate on surface modified PCL nanofibrous scaffolds expressing bipolar elongations, retaining their normal morphology. The results of our study showed that plasma treated PCL nanofibrous scaffolds are a cost-effective material compared to PCL/collagen scaffolds, and can potentially serve as an ideal tissue engineered scaffold, especially for peripheral nerve regeneration.

  7. Development of high performance nano-porous polyethersulfone ultrafiltration membranes with hydrophilic surface and superior antifouling properties

    International Nuclear Information System (INIS)

    Rahimpour, Ahmad; Madaeni, Sayed Siavash; Jahanshahi, Mohsen; Mansourpanah, Yaghoub; Mortazavian, Narmin

    2009-01-01

    Hydrophilic nano-porous polyethersulfone ultrafiltration membranes were developed for milk concentration. The membranes were prepared from new dope solution containing polyethersulfone (PES)/polyvinylpirrolidone (PVP)/polyethyleneglycole (PEG)/cellulose acetate phthalate (CAP)/acrylic acid/Triton X-100 using phase inversion induced by immersion precipitation technique. This casting solution leads to formation of new hydrophilic membranes. The morphological studies were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the hydrophilicity and performance of membranes were examined by contact angel measurements and cross-flow filtration (pure water flux, milk water permeation, protein rejection and antifouling measurements). The contact angle measurements indicate that a surface with superior hydrophilicity was obtained for PES membranes. Two concentrations of PES (16 and 14.4 wt.%) and two different non-solvents (pure water and mixtures of water and IPA) were used for preparation of membranes. The morphological studies showed that the higher concentration of PES and the presence of IPA in the gelation media results in formation of a membrane with a dense top and sub-layer with small pores on the surface. The pure water flux of membranes was decreased when higher polymer concentration and mixtures of water and IPA were employed for membrane formation. On the other hand, the milk water permeation and protein rejection were increased using mixtures of water and IPA as non-solvent. Furthermore, the fouling analysis of the membranes demonstrated that the membrane surface with fewer tendencies for fouling was obtained.

  8. Bacterial biofilms utilization of low concentrations of organic matter on hydrophile surfaces submerged in seawater

    Directory of Open Access Journals (Sweden)

    Aurelia Manuela Moldoveanu

    2011-12-01

    Full Text Available A series of experiments were designed to determine the effect and the metabolic rate utilization of various types of organic matter in low concentration by heterotrophic marine bacteria using as Henrici slide technique as culture method and “in vitro” static conditions in sterile containers in order to obtain bacterial biofilms on the hydrophile surface of glass. The bacteria attachment and biofilm formation was analyzed for a period from 2 hours to 72 hours in order to observe de first phase of biofilm formation in condition of seawater supplied  with organic matter and noninvasive optic microscopy analysis. The utilization of five different  types of organic substances (amino-acid mixture, yeast extract, tryptone, glucose and starch reveled that bacteria multiply and are otherwise physiologically active in this very dilute nutrient solutions of 0.1% and also the results revealed that the bacterial growth was considerable in the case of the substances like amino-acid mixture with a total density of 30.9∙103 cells/mm2  and tryptone with a total density of 28.85∙103 cells/mm2  comparable to the other types of organic matter used to supply the seawater

  9. [The effect of hydrophobic surface properties of protein on its resistance to denaturation by organic solvents (using modified alpha-chymotrypsin as an example].

    Science.gov (United States)

    Kudriashova, E V; Belova, A B; Vinogradov, A A; Mozhaev, V V

    1994-03-01

    Catalytic activity of covalently modified alpha-chymotrypsin in water/cosolvent solutions was investigated. The stability of chymotrypsin increases upon modification with hydrophilic reagents, such as glyceraldehyde, pyrometallic and succinic anhydrides, and glucosamine. Correlation was observed between the protein's stability in organic solvents and the degree of hydrophilization of the protein's surface. The protein is the more stable, the higher are the modification degree and the hydrophilicity of the modifying residue. At a certain critical hydrophilization degree of chymotrypsin a limit of stability is achieved. The stabilization effect can be accounted for by the fact that the interaction between water molecules on the surface and protein's functional groups become stronger in the hydrophilized protein.

  10. Immunoglobulin adsorption on modified surfaces

    NARCIS (Netherlands)

    Bremer, M.G.E.G.

    2001-01-01

    Preservation of biological functioning of proteins during immobilisation is of special interest in various biomedical and biotechnical applications. In industry physical adsorption of immunoglobulins (IgGs) onto solid surfaces is still the predominant immobilisation procedure because it is

  11. Temporal Changes in Extracellular Polymeric Substances on Hydrophobic and Hydrophilic Membrane Surfaces in a Submerged Membrane Bioreactor

    KAUST Repository

    Matar, Gerald Kamil

    2016-03-02

    Membrane surface hydrophilic modification has always been considered to mitigating biofouling in membrane bioreactors (MBRs). Four hollow-fiber ultrafiltration membranes (pore sizes ∼0.1 μm) differing only in hydrophobic or hydrophilic surface characteristics were operated at a permeate flux of 10 L/m2.h in the same lab-scale MBR fed with synthetic wastewater. In addition, identical membrane modules without permeate production (0 L/m2.h) were operated in the same lab-scale MBR. Membrane modules were autopsied after 1, 10, 20 and 30 days of MBR operation, and total extracellular polymeric substances (EPS) accumulated on the membranes were extracted and characterized in detail using several analytical tools, including conventional colorimetric tests (Lowry and Dubois), liquid chromatography with organic carbon detection (LC-OCD), fluorescence excitation - emission matrices (FEEM), fourier transform infrared (FTIR) and confocal laser scanning microscope (CLSM). The transmembrane pressure (TMP) quickly stabilized with higher values for the hydrophobic membranes than hydrophilic ones. The sulfonated polysulfone (SPSU) membrane had the highest negatively charged membrane surface, accumulated the least amount of foulants and displayed the lowest TMP. The same type of organic foulants developed with time on the four membranes and the composition of biopolymers shifted from protein dominance at early stages of filtration (day 1) towards polysaccharides dominance during later stages of MBR filtration. Nonmetric multidimensional scaling of LC-OCD data showed that biofilm samples clustered according to the sampling event (time) regardless of the membrane surface chemistry (hydrophobic or hydrophilic) or operating mode (with or without permeate flux). These results suggest that EPS composition may not be the dominant parameter for evaluating membrane performance and possibly other parameters such as biofilm thickness, porosity, compactness and structure should be considered

  12. Radius ratio rule for surface hydrophilization of polydimethyl siloxane and silica nanoparticle composite

    Energy Technology Data Exchange (ETDEWEB)

    Toutam, Vijaykumar, E-mail: toutamvk@nplindia.org [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Jain, Puneet; Sharma, Rina [Quantum Phenomena and Applications Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Bathula, Sivaiah; Dhar, Ajay [Material Physics and Engineering Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

    2015-09-15

    Graphical abstract: - Highlights: • Binary hard sphere silica nanoparticle system based PDMS composite. • Enhanced hydrophilization and retainability of the composite. • Restriction of uncured PDMS from diffusion. • Increased Debye length of electrostatic double layer, measured by F-D Spectroscopy. - Abstract: Polydimethyl siloxane (PDMS) and Silica (SiO{sub 2}) nanoparticle composite blocks of three different batches (CB1–CB3) made by varying the size of SiO{sub 2} nanoparticles (NP), are studied for the degree of hydrophilization and retainability after oxidation by contact angle measurements (CA) and force distance spectroscopy (FDS) using Atomic Force Microscope (AFM). While CA measurements have shown high hydrophilization and retainability for CB3, F-D spectroscopy has reiterated the observation and has shown long range interactive forces and high Debye length of the electrostatic double layer formed. These results are in agreement with the radius ratio rule of binary sphere system for high density packing in the composite and thereby for strong hydrophilization and retainability due to reinforcement and restricted diffusion of uncured polymer.

  13. Six-Year Survival and Early Failure Rate of 2918 Implants with Hydrophobic and Hydrophilic Enossal Surfaces

    Directory of Open Access Journals (Sweden)

    Olivier Le Gac

    2015-02-01

    Full Text Available The aim of this chart review was to obtain an objective, quantitative assessment of the clinical performance of an implant line used in an implantological office setting. Implants with hydrophilic (INICELL and hydrophobic (TST; both: Thommen Medical AG, Grenchen, Switzerland enossal surfaces were compared and the cumulative implant survival rate was calculated. The data of 1063 patients that received 2918 implants (1337 INICELL, 1581 TST was included. The average follow up time was 2.1 (1.1–5.4 years for INICELL and 4.5 (1.3–5.9 years for TST implants (Thommen Medical AG, Switzerland. In the reported period 7 implants with INICELL (0.5% and 23 TST implants (1.5% failed. This difference was statistically significant. The analysis of cases treated and followed up in a single implantological office for 6 years confirmed the very good clinical outcome that was achieved with both used implant lines. Within the limitations of this retrospective analysis, the overall early failure rate of the hydrophilic implants was significantly lower than that of hydrophobic implants. The use of hydrophilic implants allows the clinician to obtain less early failures, hence the interest of an up-to-date surface for the daily work of an implant practice.

  14. Six-Year Survival and Early Failure Rate of 2918 Implants with Hydrophobic and Hydrophilic Enossal Surfaces.

    Science.gov (United States)

    Gac, Olivier Le; Grunder, Ueli

    2015-02-05

    The aim of this chart review was to obtain an objective, quantitative assessment of the clinical performance of an implant line used in an implantological office setting. Implants with hydrophilic (INICELL) and hydrophobic (TST; both: Thommen Medical AG, Grenchen, Switzerland) enossal surfaces were compared and the cumulative implant survival rate was calculated. The data of 1063 patients that received 2918 implants (1337 INICELL, 1581 TST) was included. The average follow up time was 2.1 (1.1-5.4) years for INICELL and 4.5 (1.3-5.9) years for TST implants (Thommen Medical AG, Switzerland). In the reported period 7 implants with INICELL (0.5%) and 23 TST implants (1.5%) failed. This difference was statistically significant. The analysis of cases treated and followed up in a single implantological office for 6 years confirmed the very good clinical outcome that was achieved with both used implant lines. Within the limitations of this retrospective analysis, the overall early failure rate of the hydrophilic implants was significantly lower than that of hydrophobic implants. The use of hydrophilic implants allows the clinician to obtain less early failures, hence the interest of an up-to-date surface for the daily work of an implant practice.

  15. Surface modification of imprinted polymer microspheres with ultrathin hydrophilic shells to improve selective recognition of glutathione in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Song, Renyuan, E-mail: songrenyuan0726@163.com; Hu, Xiaoling; Guan, Ping; Li, Ji; Du, Chunbao; Qian, Liwei; Wang, Chaoli

    2016-03-01

    A universal, effective approach addressing the classical limitations of hydrophobic molecularly imprinted polymer (MIP) microspheres was described. Two water-compatible MIP microspheres with ultrathin hydrophilic shells were synthesized by controllable surface-graft polymerization using a charged monomer (methacrylic acid) and uncharged monomer (N-isopropylacrylamide) as the hydrophilic functional monomers for the recognition of glutathione in the aqueous medium. The morphological and chemical characteristics of the as-prepared water-compatible MIP microspheres were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy and contact angle measurements. Their selective recognition properties were investigated by static binding tests and compared with those of the ungrafted MIP microspheres. The results of this study showed that the both as-prepared water-compatible MIP microspheres effectively decreased non-specific binding and enhanced the imprinting factor significantly, and the water-compatible MIP microspheres prepared using N-isopropylacrylamide as monomer exhibited a more remarkable recognition property. In addition, the thickness of surface-grafted hydrophilic layer was well controlled by adjusting the irradiation time to obtain the excellent recognition property. Finally, the applicability of the as-prepared water-compatible MIP microspheres as solid-phase extraction materials was investigated by competitive binding tests using a mixture of glutathione and its analogs. - Highlights: • Ultrathin hydrophilic shell was synthesized by controllable SIP approach. • Low nonspecific binding, high imprinting factor and selectivity were achieved. • Value of imprinting factor was controlled by adjusting irradiation time. • Selective solid-phase extraction of glutathione from a mixed solution of peptides.

  16. Effects of surface hydrophilicity and microtopography on early stages of soft and hard tissue integration at non-submerged titanium implants: an immunohistochemical study in dogs.

    Science.gov (United States)

    Schwarz, Frank; Ferrari, Daniel; Herten, Monika; Mihatovic, Ilja; Wieland, Marco; Sager, Martin; Becker, Jürgen

    2007-11-01

    The aim of the present study was to investigate the effects of surface hydrophilicity and microtopography on soft and hard tissue integration at non-submerged titanium implants. Implantation of conventional sand-blasted large grit and acid-etched (SLA) and chemically modified SLA (modSLA) titanium implants with differently structured transmucosal surfaces (SLA implants: machined [M-SLA] or SLA [SLA-SLA]; modSLA implants: mod acid-etched [modA] [modA-modSLA] or modSLA [modSLA-modSLA]) was performed bilaterally in the upper and lower jaws of 15 beagle dogs. The animals were sacrificed after 1, 4, 7, 14, or 28 days. Tissue reactions were assessed histomorphometrically and immunohistochemically using monoclonal antibodies to transglutaminase II (angiogenesis) and osteocalcin. Although the junctional epithelium commonly was separated from M-SLA and SLA-SLA implants by a gap, the epithelial cells appeared to be in close contact with modA-modSLA surfaces after 14 days of healing. Moreover, modA-modSLA and modSLA-modSLA groups showed a well-vascularized subepithelial connective tissue exhibiting collagen fibers that started to extend and attach partially perpendicular to the implant surface. The highest and statistically significant mean bone-to-implant contact areas were observed in the modA-modSLA and modSLA-modSLA groups at days 7, 14, and 28. Within the limits of this study, it may be concluded that soft and hard tissue integration was influenced mainly by surface hydrophilicity rather than by microtopography.

  17. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O{sub 2}/H{sub 2}O low-temperature plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    You, Xuewei; Gou, Li, E-mail: gouli@scu.edu.cn; Tong, Xingye

    2016-01-01

    Graphical abstract: - Highlights: • O{sub 2}/H{sub 2}O can increase oxygen concentration in the plasma compared to the pure O{sub 2} atmosphere. • Pores at the surface of natural leather became larger and deeper with enhanced permeability of water. • The initial water contact angle was about 21°. • Its preferable surface hydrophilicity kept for 3 days, which gives guidance for next process. • The elongation of the treated sample for 10 min was twice as large as that of the untreated sample. - Abstract: The natural leather was modified through O{sub 2}/H{sub 2}O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O{sub 2}/H{sub 2}O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  18. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O_2/H_2O low-temperature plasma treatment

    International Nuclear Information System (INIS)

    You, Xuewei; Gou, Li; Tong, Xingye

    2016-01-01

    Graphical abstract: - Highlights: • O_2/H_2O can increase oxygen concentration in the plasma compared to the pure O_2 atmosphere. • Pores at the surface of natural leather became larger and deeper with enhanced permeability of water. • The initial water contact angle was about 21°. • Its preferable surface hydrophilicity kept for 3 days, which gives guidance for next process. • The elongation of the treated sample for 10 min was twice as large as that of the untreated sample. - Abstract: The natural leather was modified through O_2/H_2O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O_2/H_2O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  19. An SFG study of interfacial amino acids at the hydrophilic SiO2 and hydrophobic deuterated polystyrene surfaces.

    Science.gov (United States)

    Holinga, George J; York, Roger L; Onorato, Robert M; Thompson, Christopher M; Webb, Nic E; Yoon, Alfred P; Somorjai, Gabor A

    2011-04-27

    Sum frequency generation (SFG) vibrational spectroscopy was employed to characterize the interfacial structure of eight individual amino acids--L-phenylalanine, L-leucine, glycine, L-lysine, L-arginine, L-cysteine, L-alanine, and L-proline--in aqueous solution adsorbed at model hydrophilic and hydrophobic surfaces. Specifically, SFG vibrational spectra were obtained for the amino acids at the solid-liquid interface between both hydrophobic d(8)-polystyrene (d(8)-PS) and SiO(2) model surfaces and phosphate buffered saline (PBS) at pH 7.4. At the hydrophobic d(8)-PS surface, seven of the amino acids solutions investigated showed clear and identifiable C-H vibrational modes, with the exception being l-alanine. In the SFG spectra obtained at the hydrophilic SiO(2) surface, no C-H vibrational modes were observed from any of the amino acids studied. However, it was confirmed by quartz crystal microbalance that amino acids do adsorb to the SiO(2) interface, and the amino acid solutions were found to have a detectable and widely varying influence on the magnitude of SFG signal from water at the SiO(2)/PBS interface. This study provides the first known SFG spectra of several individual amino acids in aqueous solution at the solid-liquid interface and under physiological conditions.

  20. Interactions between nano-TiO2 and the oral cavity: impact of nanomaterial surface hydrophilicity/hydrophobicity.

    Science.gov (United States)

    Teubl, Birgit J; Schimpel, Christa; Leitinger, Gerd; Bauer, Bettina; Fröhlich, Eleonore; Zimmer, Andreas; Roblegg, Eva

    2015-04-09

    Titanium dioxide (TiO2) nanoparticles are available in a variety of oral applications, such as food additives and cosmetic products. Thus, questions about their potential impact on the oro-gastrointestinal route rise. The oral cavity represents the first portal of entry and is known to rapidly interact with nanoparticles. Surface charge and size contribute actively to the particle-cell interactions, but the influence of surface hydrophilicity/hydrophobicity has never been shown before. This study addresses the biological impact of hydrophilic (NM 103, rutile, 20 nm) and hydrophobic (NM 104, rutile, 20 nm) TiO2 particles within the buccal mucosa. Particle characterization was addressed with dynamic light scattering and laser diffraction. Despite a high agglomeration tendency, 10% of the particles/agglomerates were present in the nanosized range and penetrated into the mucosa, independent of the surface properties. However, significant differences were observed in intracellular particle localization. NM 104 particles were found freely distributed in the cytoplasm, whereas their hydrophobic counterparts were engulfed in vesicular structures. Although cell viability/membrane integrity was not affected negatively, screening assays demonstrated that NM 104 particles showed a higher potential to decrease the physiological mitochondrial membrane potential than NM 103, resulting in a pronounced generation of reactive oxygen species. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Evolution and accumulation of organic foulants on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor

    KAUST Repository

    Matar, Gerald

    2015-09-07

    Membrane surface modification is attracting more attention to mitigate biofouling in membrane bioreactors (MBRs). Five membranes differing in chemistry and hydrophobic/hydrophilic potential were run in parallel in a lab-scale MBR under the same conditions. Membranes were sampled after 1, 10, 20 and 30 days of MBR operation with synthetic wastewater. Subsequently, accumulated organic foulants were characterised using several chemical analytical tools. Results showed similar development of organic foulants with time, illustrating that membrane surface chemistry did not affect the selection of specific organic foulants. Multivariate analysis showed that biofilm samples clustered according to the day of sampling. The composition of organic foulants shifted from protein-like substances towards humics and polysaccharides-like substances. We propose that to control biofouling in MBRs, one should focus less on the membrane surface chemistry.

  2. Chemical functionalization of ceramic tile surfaces by silane coupling agents: polymer modified mortar adhesion mechanism implications

    Directory of Open Access Journals (Sweden)

    Alexandra Ancelmo Piscitelli Mansur

    2008-09-01

    Full Text Available Adhesion between tiles and mortars are crucial to the stability of ceramic tile systems. From the chemical point of view, weak forces such as van der Waals forces and hydrophilic interactions are expected to be developed preferably at the tiles and polymer modified Portland cement mortar interface. The main goal of this paper was to use organosilanes as primers to modify ceramic tile hydrophilic properties to improve adhesion between ceramic tiles and polymer modified mortars. Glass tile surfaces were treated with several silane derivatives bearing specific functionalities. Contact angle measurements and Fourier Transform Infrared Spectroscopy (FTIR were used for evaluating the chemical changes on the tile surface. In addition, pull-off tests were conducted to assess the effect on adhesion properties between tile and poly(ethylene-co-vinyl acetate, EVA, modified mortar. The bond strength results have clearly shown the improvement of adherence at the tile-polymer modified mortar interface, reflecting the overall balance of silane, cement and polymer interactions.

  3. A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro.

    Directory of Open Access Journals (Sweden)

    Chundong Liu

    Full Text Available To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti surfaces modified with strontium (Sr for bone implant applications.Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts.The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes.These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C.

  4. A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro.

    Science.gov (United States)

    Liu, Chundong; Zhang, Yanli; Wang, Lichao; Zhang, Xinhua; Chen, Qiuyue; Wu, Buling

    2015-01-01

    To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications. Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts. The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes. These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C.

  5. Photocatalysis of Modified Transition Metal Oxide Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Batzill, Matthias [Univ. of South Florida, Tampa, FL (United States). Dept. of Physics

    2018-02-28

    The goal of this project has been to establish a cause-effect relationship for photocatalytic activity variations of different structures of the same material; and furthermore gain fundamental understanding on modification of photocatalysts by compositional or surface modifications. The reasoning is that gaining atomic scale understanding of how surface and bulk modifications alter the photo reactivity will lead to design principles for next generation photocatalysts. As a prototypical photocatalyst the research focused on TiO2 synthesized in well-defined single crystalline form to enable fundamental characterizations.We have obtained results in the following areas: (a) Preparation of epitaxial anatase TiO2 samples by pulsed laser deposition. (b) Comparison of hydrogen diffusion on different crystallographic surface. (c) Determining the stability of the TiO2(011)-2x1 reconstruction upon interactions with adsorbates. (d) Characterization of adsorption and (thermal and photo) reaction of molecules with nitro-endgroups, (e) Exploring the possibility of modifying planar model photocatalyst surfaces with graphene to enable fundamental studies on reported enhanced photocatalytic activities of graphene modified transition metal oxides, (f) gained fundamental understanding on the role of crystallographic polymorphs of the same material for their photocatalytic activities.

  6. Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

    International Nuclear Information System (INIS)

    Kamgang, J. O.; Brisset, J.-L.; Naitali, M.; Herry, J.-M.; Bellon-Fontaine, M.-N.; Briandet, R.

    2009-01-01

    This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a model bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafluoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. Moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested. (plasma technology)

  7. Labile conjugation of a hydrophilic drug to PLA oligomers to modify a drug delivery system: cephradin in a PLAGA matrix.

    Science.gov (United States)

    Ustariz-Peyret, C; Coudane, J; Vert, M; Kaltsatos, V; Boisramené, B

    2000-01-01

    The physical entrapment of a hydrophilic drug within degradable microspheres is generally difficult because of poor entrapment yield and/or fast release, depending on the microsphere fabrication method. In order to counter the effects of drug hydrophilicity, it is proposed to covalently attach the drug to lactic acid oligomers, with the aim of achieving temporary hydrophobization and slower release controlled by the separation of the drug from the degradable link within the polymer matrix. This strategy was tested on microspheres of the antibiotic cephradin. As the prodrug form, the entrapment of the drug was almost quantitative. The prodrug did degrade in an aqueous medium, modelling body fluids, but cleavage did not occur at the drug-oligomer junction and drug molecules bearing two lactyl residual units were released. When the prodrug is entrapped within a PLAGA matrix, no release was observed within the experimental time period. However, data suggest that conjugation via a bond more sensitive to hydrolysis than the main chain PLA ester bonds should make the system work as desired.

  8. Preparation and evaluation of a hydrophilic interaction and cation-exchange chromatography stationary phase modified with 2-methacryloyloxyethyl phosphorylcholine.

    Science.gov (United States)

    Xiong, Caifeng; Yuan, Jie; Wang, Zhiying; Wang, Siyao; Yuan, Chenchen; Wang, Lili

    2018-04-20

    In this work, 2-methacryloyloxyethyl phosphorylcholine (MPC) was used as a ligand to prepare a novel mixed-mode chromatography (MMC) stationary phase by the thiol-ene click reaction onto silica (MPC-silica). It was found that this MPC-silica showed the retention characteristics of hydrophilic interaction chromatography (HILIC) and weak cation exchange chromatography (WCX) under suitable mobile phase conditions. In detail, acidic and basic hydrophilic compounds and puerarin from pueraria were separated quickly with HILIC mode. Meanwhile, six standard proteins were allowed to reach baseline separation in WCX mode, and protein separation from egg white was also achieved with this mode. In addition, reduced/denatured lysozyme could be refolded with the MPC-silica column. In the meantime, the MPC-silica has been applied for refolding with simultaneous purification of recombinant human Delta-like1-RGD (rhDll1-RGD) expressed in Escherichia coli. The results show that the mass recovery and purity of rhDll1-RGD could reach 63.4% and 97% by one step, respectively. Furthermore, the reporter assay results demonstrated that refolded with simultaneously purified rhDll1-RGD could efficiently activate the signalling pathway in a dose-dependent manner. In general, this MPC-silica has good resolution and selectivity in the separation of polar compounds and protein samples in different high-performance liquid chromatography (HPLC) modes, and it successfully achieved refolding with simultaneous purification of denatured protein. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Possible Time-Dependent Effect of Ions and Hydrophilic Surfaces on the Electrical Conductivity of Aqueous Solutions

    Science.gov (United States)

    Verdel, Nada; Jerman, Igor; Krasovec, Rok; Bukovec, Peter; Zupancic, Marija

    2012-01-01

    The purpose of this work was to determine the influence of mechanical and electrical treatment on the electrical conductivity of aqueous solutions. Solutions were treated mechanically by iteration of two steps: 1:100 dilution and vigorous shaking. These two processes were repeated until extremely dilute solutions were obtained. For electrical treatment the solutions were exposed to strong electrical impulses. Effects of mechanical (as well as electrical) treatment could not be demonstrated using electrical conductivity measurements. However, significantly higher conductivity than those of the freshly prepared chemically analogous solutions was found in all aged solutions except for those samples stored frozen. The results surprisingly resemble a previously observed weak gel-like behavior in water stored in closed flasks. We suggest that ions and contact with hydrophilic glass surfaces could be the determinative conditions for the occurrence of this phenomenon. PMID:22605965

  10. Modulating Protein Adsorption on Oxygen Plasma Modified Polysiloxane Surfaces

    International Nuclear Information System (INIS)

    Marletta, G.

    2006-01-01

    In the present paper we report the study on the adsorption behaviour of three model globular proteins, Human Serum Albumin, Lactoferrin and Egg Chicken Lysozyme onto both unmodified surfaces of a silicon-based polymer and the corresponding plasma treated surfaces. In particular, thin films of hydrophobic polysiloxane (about 90 degree of static water contact angle, WCA) were converted by oxygen plasma treatment at reduced pressure into very hydrophilic phases of SiOx (WCA less than 5 degree). The kinetics of protein adsorption processes were investigated by QCM-D technique, while the chemical structure and topography of the protein adlayer have been studied by Angular resolved-XPS and AFM respectively. It turned out that Albumin and Lysozyme exhibited the opposite preferential adsorption respectively onto the hydrophobic and hydrophilic surfaces, while Lactoferrin did not exhibit significant differences. The observed protein behaviour are discussed both in terms of surface-dependent parameters, including surface free energy and chemical structure, and in terms of protein-dependent parameters, including charge as well as the average molecular orientation in the adlayers. Finally, some examples of differential adsorption behaviour of the investigated proteins are reported onto nanopatterned polysiloxane surfaces consisting of hydrophobic nanopores surrounded by hydrophilic (plasma-treated) matrix and the reverse

  11. Protein repellent hydrophilic grafts prepared by surface-initiated atom transfer radical polymerization from polypropylene

    DEFF Research Database (Denmark)

    Fristrup, Charlotte Juel; Jankova Atanasova, Katja; Eskimergen, Rüya

    2012-01-01

    with Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FTIR) spectroscopy and Water Contact Angle (WCA) measurements. Confocal fluorescence microscopy of modified and unmodified substrates immersed in labelled insulin aspart showed superior repulsion of this protein for the poly(PEGMA) grafts, due...

  12. Molecular dynamics simulations of water on a hydrophilic silica surface at high air pressures

    DEFF Research Database (Denmark)

    Zambrano, H.A.; Walther, Jens Honore; Jaffe, R.L.

    2014-01-01

    Wepresent a force field forMolecular Dynamics (MD) simulations ofwater and air in contactwith an amorphous silica surface. We calibrate the interactions of each species present in the systemusing dedicated criteria such as the contact angle of a water droplet on a silica surface, and the solubility...

  13. Selective three-dimensional hydrophilization of microstructured polymer surfaces through confined photocatalytic oxidation

    International Nuclear Information System (INIS)

    Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

    2015-01-01

    Graphical abstract: - Highlights: • Microstructured polymer surfaces with selective 3-D anisotropy were created. • Selective UV treatment was performed to alter surface wettability. • Removable meshes resembling a photomask were applied during UV treatment. • Micropatterning by viscous polymer on solid surface was performed. - Abstract: While the conventional photomask technique gives only two-dimensional anisotropies, in this study we fabricated microstructured polymer surfaces with a selective three-dimensional anisotropy. With the applied removable mesh, we were able to confine the contacting area between the surface and photoinitiator and provide three-dimensional wettability anisotropies. Different types of meshes were used depending on the desired micropatterns shape, size and substrate material. The results revealed the three-dimensional anisotropic micropits pattern with depth profiles, which would be applicable for the confinement and patterning of cells and biomolecules. In addition, the proposed method is applicable for creating selectively activated polymer surface as a substrate for further atomic layer deposition. Moreover, we demonstrate a low cost and fast mass productive method for patterning a viscous polymer liquid in a micro-sized scale

  14. The surface reactivity of chalk (biogenic calcite) with hydrophilic and hydrophobic functional groups

    Science.gov (United States)

    Okhrimenko, D. V.; Dalby, K. N.; Skovbjerg, L. L.; Bovet, N.; Christensen, J. H.; Stipp, S. L. S.

    2014-03-01

    The surface properties of calcium carbonate minerals play an important role in a number of industrial and biological processes. Properties such as wettability and adsorption control liquid-solid interface behaviour and thus have a strong influence on processes such as biomineralisation, remediation of aquifers and oil recovery. We investigated how two model molecules of different polarity, namely water and ethanol, interact with reservoir and outcrop chalk samples and we compared their behaviour with that of pure, inorganically precipitated calcite. Thermodynamic quantities, such as the work of wetting, surface energy and isosteric adsorption enthalpy, were determined from vapour adsorption isotherms. The chalks were studied fresh and after extraction of organic residues that were originally present in these samples. The work of wetting correlates with the amount of organic matter present in the chalk samples but we observed a fundamental difference between the adsorption properties of chalk and pure, inorganically precipitated calcite toward the less polar, ethanol molecule. Further analysis of the chemical composition of the organic matter extracted from the chalk samples was made by gas chromatography (GC-MS). Monitoring surface composition by X-ray photoelectron spectroscopy (XPS) before and after extraction of the organic material, and with atomic force microscopy (AFM), showed that nanometer sized clay crystals observed on the chalk particle surfaces could be an important part of the reason for the differences. Removal of the extractable portion of the hydrocarbons liberates adsorption sites that have different wetting properties than the rest of the chalk and these have an energy distribution that is similar to clays. Thus, the results exemplify the complexity of biogenic calcite adsorption behaviour and demonstrate that chalk wetting in drinking water aquifers as well as oil reservoirs is controlled partly by the nanoparticles of clay that have grown on the

  15. Hydrophilization of Poly(ether ether ketone) Films by Surface-initiated Atom Transfer Radical Polymerization

    DEFF Research Database (Denmark)

    Fristrup, Charlotte Juel; Eskimergen, Rüya; Burkrinsky, J.T.

    2008-01-01

    and confirmed by ATR FTIR, water contact ang;le, and Thermal Gravimetric Analysis (TGA). The surface topography was evaluated by "Atomic Force Microscopy (AFM). X-ray Photoelectron Spectroscopy (XPS) has been used to investigate the degree of functionalization. The performed modification allowed for successful...

  16. Hydrophilic structures for condensation management in appliances

    Science.gov (United States)

    Kuehl, Steven John; Vonderhaar, John J.; Wu, Guolian; Wu, Mianxue

    2016-02-02

    An appliance that includes a cabinet having an exterior surface; a refrigeration compartment located within the cabinet; and a hydrophilic structure disposed on the exterior surface. The hydrophilic structure is configured to spread condensation. The appliance further includes a wicking structure located in proximity to the hydrophilic structure, and the wicking structure is configured to receive the condensation.

  17. Using heat-treated starch to modify the surface of biochar and improve the tensile properties of biochar-filled stryene-butadiene rubber composites

    Science.gov (United States)

    Heat-treated starch is a renewable material that can be used to modify the surface chemistry of small particles. In this work, heat-treated starch was used to coat hydrophilic biochar particles in order to make them more hydrophobic. Then when added as filler to hydrophobic styrene-butadiene rubber,...

  18. Hydrophilic surface modification of coronary stent using an atmospheric pressure plasma jet for endothelialization.

    Science.gov (United States)

    Shim, Jae Won; Bae, In-Ho; Park, Dae Sung; Lee, So-Youn; Jang, Eun-Jae; Lim, Kyung-Seob; Park, Jun-Kyu; Kim, Ju Han; Jeong, Myung Ho

    2018-03-01

    The first two authors contributed equally to this study. Bioactivity and cell adhesion properties are major factors for fabricating medical devices such as coronary stents. The aim of this study was to evaluate the advantages of atmospheric-pressure plasma jet in enhancing the biocompatibility and endothelial cell-favorites. The experimental objects were divided into before and after atmospheric-pressure plasma jet treatment with the ratio of nitrogen:argon = 3:1, which is similar to air. The treated surfaces were basically characterized by means of a contact angle analyzer for the activation property on their surfaces. The effect of atmospheric-pressure plasma jet on cellular response was examined by endothelial cell adhesion and XTT analysis. It was difficult to detect any changeable morphology after atmospheric-pressure plasma jet treatment on the surface. The roughness was increased after atmospheric-pressure plasma jet treatment compared to nonatmospheric-pressure plasma jet treatment (86.781 and 7.964 nm, respectively). The X-ray photoelectron spectroscopy results showed that the surface concentration of the C-O groups increased slightly from 6% to 8% after plasma activation. The contact angle dramatically decreased in the atmospheric-pressure plasma jet treated group (22.6 ± 15.26°) compared to the nonatmospheric-pressure plasma jet treated group (72.4 ± 15.26°) ( n = 10, p atmospheric-pressure plasma jet on endothelial cell migration and proliferation was 85.2% ± 12.01% and 34.2% ± 2.68%, respectively, at 7 days, compared to the nonatmospheric-pressure plasma jet treated group (58.2% ± 11.44% in migration, n = 10, p atmospheric-pressure plasma jet method. Moreover, the atmospheric-pressure plasma jet might affect re-endothelialization after stenting.

  19. Poly(ethylene glycol)-grafted cyclic acetals based polymer networks with non-water-swellable, biodegradable and surface hydrophilic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ruixue, E-mail: qdruinyan@hotmail.com [Complex and Intelligent Research Center, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China); Zhang, Nan; Wu, Wentao [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Wang, Kemin, E-mail: kemin-wang@hotmail.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China)

    2016-05-01

    Cyclic acetals based biomaterial without acidic products during hydrolytic degradation is a promising candidate for tissue engineering applications; however, low hydrophilicity is still one limitation for its biomedical application. In this work, we aim to achieve non-water-swellable cyclic acetal networks with improved hydrophilicity and surface wettability by copolymerization of cyclic acetal units based monomer, 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1, 3-dioxane-2-ethanol diacrylate (EHD) and methoxy poly(ethylene glycol) monoacrylate (mPEGA) under UV irradiation, to avoid swelling of conventional hydrogels which could limit their applicability in particular of the mechanical properties and geometry integrity. Various EHD/mPEGA networks were fabricated with different concentrations of mPEGA from 0 to 30%, and the results showed photopolymerization behavior, mechanical property and thermal stability could not be significantly affected by addition of mPEGA, while the surface hydrophilicity was dramatically improved with the increase of mPEGA and could achieve a water contact angle of 37° with 30% mPEGA concentration. The obtained EHD/mPEGA network had comparative degradation rate to the PECA hydrogels reported previously, and MTT assay indicated it was biocompatible to L929 cells. - Highlights: • Cyclic acetals contained EHD/mPEGA networks were fabricated by photopolymerization. • It can be degraded under simulated physiological condition without acidic products. • Surface hydrophilicity was increased without swelling in water.

  20. Boundary layers of aqueous surfactant and block copolymer solutions against hydrophobic and hydrophilic solid surfaces

    International Nuclear Information System (INIS)

    Steitz, Roland; Schemmel, Sebastian; Shi Hongwei; Findenegg, Gerhard H

    2005-01-01

    The boundary layer of aqueous surfactants and amphiphilic triblock copolymers against flat solid surfaces of different degrees of hydrophobicity was investigated by neutron reflectometry (NR), grazing incidence small angle neutron scattering (GISANS) and atomic force microscopy (AFM). Solid substrates of different hydrophobicities were prepared by appropriate surface treatment or by coating silicon wafers with polymer films of different chemical natures. For substrates coated with thin films (20-30 nm) of deuterated poly(styrene) (water contact angle θ w ∼ 90), neutron reflectivity measurements on the polymer/water interface revealed a water depleted liquid boundary layer of 2-3 nm thickness and a density about 90% of the bulk water density. No pronounced depletion layer was found at the interface of water against a less hydrophobic polyelectrolyte coating (θ w ∼ 63). It is believed that the observed depletion layer at the hydrophobic polymer/water interface is a precursor of the nanobubbles which have been observed by AFM at this interface. Decoration of the polymer coatings by adsorbed layers of nonionic C m E n surfactants improves their wettability by the aqueous phase at surfactant concentrations well below the critical micellar concentration (CMC) of the surfactant. Here, GISANS experiments conducted on the system SiO 2 /C 8 E 4 /D 2 O reveal that there is no preferred lateral organization of the C 8 E 4 adsorption layers. For amphiphilic triblock copolymers (PEO-PPO-PEO) it is found that under equilibrium conditions they form solvent-swollen brushes both at the air/water and the solid/water interface. In the latter case, the brushes transform to uniform, dense layers after extensive rinsing with water and subsequent solvent evaporation. The primary adsorption layers maintain properties of the precursor brushes. In particular, their thickness scales with the number of ethylene oxide units (EO) of the block copolymer. In the case of dip-coating without

  1. Modified alignment CGHs for aspheric surface test

    Science.gov (United States)

    Song, Jae-Bong; Yang, Ho-Soon; Rhee, Hyug-Gyo; Lee, Yun-Woo

    2009-08-01

    Computer Generated Holograms (CGH) for optical test are commonly consisted of one main pattern for testing aspheric surface and some alignment patterns for aligning the interferometer, CGH, and the test optics. To align the CGH plate and the test optics, we designed the alignment CGHs modified from the cat's eye alignment method, which are consisted of a couple of CGH patterns. The incident beam passed through the one part of the alignment CGH pattern is focused onto the one radius position of the test aspheric surface, and is reflected to the other part, and vice versa. This method has several merits compared to the conventional cat's eye alignment method. First, this method can be used in testing optics with a center hole, and the center part of CGH plate can be assigned to the alignment pattern. Second, the alignment pattern becomes a concentric circular arc pattern. The whole CGH patterns including the main pattern and alignment patterns are consisted of only concentric circular fringes. This concentric circular pattern can be easily made by the polar coordinated writer with circular scanning. The required diffraction angle becomes relatively small, so the 1st order diffraction beams instead of the 3rd order diffraction beam can be used as alignment beams, and the visibility can be improved. This alignment method also is more sensitive to the tilt and the lateral shift of the test aspheric surface. Using this alignment pattern, a 200 mm diameter F/0.5 aspheric mirror and a 600 mm diameter F/0.9 mirror were tested.

  2. Fast wettability transition from hydrophilic to superhydrophobic laser-textured stainless steel surfaces under low-temperature annealing

    Science.gov (United States)

    Ngo, Chi-Vinh; Chun, Doo-Man

    2017-07-01

    Recently, the fabrication of superhydrophobic metallic surfaces by means of pulsed laser texturing has been developed. After laser texturing, samples are typically chemically coated or aged in ambient air for a relatively long time of several weeks to achieve superhydrophobicity. To accelerate the wettability transition from hydrophilicity to superhydrophobicity without the use of additional chemical treatment, a simple annealing post process has been developed. In the present work, grid patterns were first fabricated on stainless steel by a nanosecond pulsed laser, then an additional low-temperature annealing post process at 100 °C was applied. The effect of 100-500 μm step size of the textured grid upon the wettability transition time was also investigated. The proposed post process reduced the transition time from a couple of months to within several hours. All samples showed superhydrophobicity with contact angles greater than 160° and sliding angles smaller than 10° except samples with 500 μm step size, and could be applied in several potential applications such as self-cleaning and control of water adhesion.

  3. Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tsui-Hsun [Institute of Biomedical Engineering, College of Engineering, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC (China); Institute of Medical Mechatronics, Chang Gung University, Tao-Yuan, Taiwan, ROC (China); Liao, Shu-Chuan [Center of Thin Film Technologies and Applications, Mingchi University of Technology, Taipei, Taiwan, ROC (China); Chen, Ying-Fang [Department of Dentistry, Yun-Lin Branch, National Taiwan University Hospital, Dou-Liu, Yun-Lin, Taiwan, ROC (China); Huang, Yi-You [Institute of Biomedical Engineering, College of Engineering, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC (China); Wei, Yi-Syuan [Department of Materials Engineering, Tatung University, 40 Zhongshan North Road, 3rd Section, Taipei 104, Taiwan, ROC (China); Tu, Shu-Ju, E-mail: sjt@cgu.edu.tw [Department of Medical Imaging and Radiological Sciences, Chang Gung University, 259 Wen-Hwa, 1st Road, Kwei-Shan, Tao-Yuan 133, Taiwan, ROC (China); Chen, Ko-Shao, E-mail: kschen@ttu.edu.tw [Department of Materials Engineering, Tatung University, 40 Zhongshan North Road, 3rd Section, Taipei 104, Taiwan, ROC (China)

    2013-06-01

    In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R{sup 2} range, 0.94–0.965, 0.934–0.972, and 0.874–0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

  4. Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

    International Nuclear Information System (INIS)

    Wu, Tsui-Hsun; Liao, Shu-Chuan; Chen, Ying-Fang; Huang, Yi-You; Wei, Yi-Syuan; Tu, Shu-Ju; Chen, Ko-Shao

    2013-01-01

    In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R 2 range, 0.94–0.965, 0.934–0.972, and 0.874–0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

  5. Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance

    Science.gov (United States)

    Wu, Tsui-Hsun; Liao, Shu-Chuan; Chen, Ying-Fang; Huang, Yi-You; Wei, Yi-Syuan; Tu, Shu-Ju; Chen, Ko-Shao

    2013-06-01

    In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R2 range, 0.94-0.965, 0.934-0.972, and 0.874-0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

  6. A comparative study of the growth of octadecyltrichlorosilane and 3-mercaptopropyltrimethoxysilane self-assembled monolayers on hydrophilic silicon surfaces

    International Nuclear Information System (INIS)

    Yang, S.-R.; Kolbesen, Bernd O.

    2008-01-01

    Self-assembled monolayers of two different organosilane precursors, methyl-terminated nonpolar n-octadecyltrichlorosilane (OTS, Cl 3 Si(CH 2 ) 17 CH 3 ) and thiol-terminated polar 3-mercaptopropyltrimethoxysilane (MPTMS, (CH 3 O) 3 SiCH 2 CH 2 CH 2 SH), were prepared separately on hydrophilic silicon surfaces by immersion in millimolar solutions of the respective precursors in toluene at room temperature. Ex situ atomic force microscopy (AFM), lateral force microscopy (LFM) and X-ray photoelectron spectroscopy (XPS) were used to study the growth and the properties of OTS and MPTMS SAMs. For OTS SAMs, generally speaking, small islands surrounded large dendrite-shaped islands. But for MPTMS SAMs, sporadic small round islands appeared, but no dendrites. The impact of the solution age was more significant on the growth of OTS SAMs than MPTMS SAMs. At the same precursor concentration and solution age, the growth of OTS SAMs was much faster than MPTMS SAMs due to the greater hydrolysis ability of Si-Cl bonds in OTS as compared with that of Si-OCH 3 bonds in MPTMS. The difference in hydrolysis ability was confirmed by the absence of a Cl signal in the XP spectrum of OTS SAMs and the existence of a C 1s peak corresponding to unhydrolyzed Si-OCH 3 bonds in the XP spectrum of MPTMS SAMs. This trend together with the difference in alkyl chain length had a strong influence on the surface morphology and coverage of these two SAMs. According to the individual adsorption behavior of the components, the predictable kinetic difficulty of preparing OTS/MPTMS mixed SAMs by co-adsorption is pointed out. Furthermore, a potential reaction condition for stepwise adsorption is suggested.

  7. Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces

    KAUST Repository

    Liu, Hongyi; Li, Yan; Krause, Wendy E.; Pasquinelli, Melissa A.; Rojas, Orlando J.

    2012-01-01

    The MesoDyn method is used to investigate associative structures in aqueous solution of a nonionic triblock copolymer consisting of poly(propylene oxide) capped on both ends with poly(ethylene oxide) chains. The effect of adsorbing (hydrophobic) and nonadsorbing (hydrophilic) solid surfaces in contact with aqueous solutions of the polymer is elucidated. The macromolecules form self-assembled structures in solution. Confinement under shear forces is investigated in terms of interfacial behavior and association. The formation of micelles under confinement between hydrophilic surfaces occurs faster than in bulk aqueous solution while layered structures assemble when the polymers are confined between hydrophobic surfaces. Micelles are deformed under shear rates of 1 μs -1 and eventually break to form persistent, adsorbed layered structures. As a result, surface damage under frictional forces is prevented. Overall, this study indicates that aqueous triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (Pluronics, EO mPO nEO m) act as a boundary lubricant for hydrophobic surfaces but not for hydrophilic ones. © 2011 American Chemical Society.

  8. Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces

    KAUST Repository

    Liu, Hongyi

    2012-01-25

    The MesoDyn method is used to investigate associative structures in aqueous solution of a nonionic triblock copolymer consisting of poly(propylene oxide) capped on both ends with poly(ethylene oxide) chains. The effect of adsorbing (hydrophobic) and nonadsorbing (hydrophilic) solid surfaces in contact with aqueous solutions of the polymer is elucidated. The macromolecules form self-assembled structures in solution. Confinement under shear forces is investigated in terms of interfacial behavior and association. The formation of micelles under confinement between hydrophilic surfaces occurs faster than in bulk aqueous solution while layered structures assemble when the polymers are confined between hydrophobic surfaces. Micelles are deformed under shear rates of 1 μs -1 and eventually break to form persistent, adsorbed layered structures. As a result, surface damage under frictional forces is prevented. Overall, this study indicates that aqueous triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (Pluronics, EO mPO nEO m) act as a boundary lubricant for hydrophobic surfaces but not for hydrophilic ones. © 2011 American Chemical Society.

  9. Effect of incorporating graphene oxide and surface imprinting on polysulfone membranes on flux, hydrophilicity and rejection of salt and polycyclic aromatic hydrocarbons from water

    Science.gov (United States)

    Kibechu, Rose Waithiegeni; Ndinteh, Derek Tantoh; Msagati, Titus Alfred Makudali; Mamba, Bhekie Briliance; Sampath, S.

    2017-08-01

    We report a significant enhancement of hydrophillity of polysulfone (Psf) membranes after modification with graphene oxide (GO) as a filler followed by surface imprinting on the surface of GO/Psf composite imprinted membranes (CIMs). The surface imprinting on the GO-Psf membrane was employed in order to enhance its selectivity towards polycyclic aromatic hydrocarbons (PAHs) in water. The CIMs were prepared through a process of phase inversion of a mixture of graphene oxide and polysulfone (Psf) in N-methylpyrrolidone (NMP). Fourier-transform spectroscopy (FT-IR) of the imprinted showed new peaks at 935 cm-1 and 1638 cm-1 indicating success in surface imprinting on the GO-Psf membrane. The CIM also showed improvement in flux from 8.56 LM-2 h-1 of unmodified polysulfone membrane to 15.3 LM-2 h-1 in the CIM, salt rejection increased from 57.2 ± 4.2% of polysulfone membrane to 76 ± 4.5%. The results obtained from the contact angle measurements showed a decrease with increase in GO content from 72 ± 2.7% of neat polysulfone membrane to 62.3 ± 2.1% of CIM indicating an improvement in surface hydrophilicity. The results from this study shows that, it is possible to improve the hydrophilicity of the membranes without affecting the performance of the membranes.

  10. Surface characterization and free thyroid hormones response of chemically modified poly(ethylene terephthalate) blood collection tubes

    Science.gov (United States)

    Jalali Dil, Ebrahim; Kim, Samuel C.; Saffar, Amir; Ajji, Abdellah; Zare, Richard N.; Sattayapiwat, Annie; Esguerra, Vanessa; Bowen, Raffick A. R.

    2018-06-01

    The surface chemistry and surface energy of chemically modified polyethylene terephthalate (PET) blood collection tubes (BCTs) were studied and the results showed a significant increase in hydrophilicity and polarity of modified PET surface. The surface modification created nanometer-sized, needle-like asperities through molecular segregation at the surface. The surface dynamics of the modified PET was examined by tracking its surface properties over a 280-day period. The results showed surface rearrangement toward a surface with lower surface energy and fewer nanometer-sized asperities. Thromboelastography (TEG) was used to evaluate and compare the thrombogenicity of the inner walls of various types of BCTs. The TEG tracings and data from various types of BCTs demonstrated differences in the reactionand coagulation times but not in clot strength. The performance of the modified tubes in free triiodothyronine (FT3) and free thyroxine (FT4) hormone tests was examined, and it was found that the interference of modified PET tubes was negligible compared to that of commercially available PET BCTs.

  11. Surface wettability control by titanium dioxide photo-induced reaction. Super-hydrophilic properties; Sanka chitan ni yoru hikari reiki shinsuika gijutsu. Hikari shokubai chosinsuisei

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T. [The University of Tokyo, Tokyo (Japan). Research Center for Advanced Science and Technology

    1999-05-01

    Hydrophilicity results when the surface of titanium dioxide is reduced for the specified oxygen to be replaced by hydroxyl groups. The ease with which such a structural change occurs is subject to variation between titanium dioxide crystal surfaces, and is dependent greatly on the atmosphere. No hydrophilic trend is observed in an atmosphere of oxygen only without moisture and, in darkness without light, hydrophobicity occurs early. Although the contacta angle titanium dioxide with water with stability is not known, yet it is presumed, on the analogy of the case of strontium titanate, that it is in the range of 20-40 degrees. A hydrophilic trend below the range is attrributed to structural changes. The control of surface wettability is one of the basic tasks to fulfill in various kinds of mechanisms and manufacturing processes. The technology of wettability control using a titanium dioxide coating which is quite durable will be applied not only to functions involving defogging, dripproof, and self-cleaning, but also to the control of heat transmission in the mechanism and to the bonding process. (NEDO)

  12. Surface wettability control by titanium dioxide photo-induced reaction. Super-hydrophilic properties. Sanka chitan ni yoru hikari reiki shinsuika gijutsu. Hikari shokubai chosinsuisei

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T. (The University of Tokyo, Tokyo (Japan). Research Center for Advanced Science and Technology)

    1999-05-01

    Hydrophilicity results when the surface of titanium dioxide is reduced for the specified oxygen to be replaced by hydroxyl groups. The ease with which such a structural change occurs is subject to variation between titanium dioxide crystal surfaces, and is dependent greatly on the atmosphere. No hydrophilic trend is observed in an atmosphere of oxygen only without moisture and, in darkness without light, hydrophobicity occurs early. Although the contacta angle titanium dioxide with water with stability is not known, yet it is presumed, on the analogy of the case of strontium titanate, that it is in the range of 20-40 degrees. A hydrophilic trend below the range is attrributed to structural changes. The control of surface wettability is one of the basic tasks to fulfill in various kinds of mechanisms and manufacturing processes. The technology of wettability control using a titanium dioxide coating which is quite durable will be applied not only to functions involving defogging, dripproof, and self-cleaning, but also to the control of heat transmission in the mechanism and to the bonding process. (NEDO)

  13. Micro-Bulges Investigation on Laser Modified Tool Steel Surface

    Directory of Open Access Journals (Sweden)

    Fauzun Fazliana

    2017-01-01

    Full Text Available This paper presents micro-bulges investigation on laser modified tool steel. The aim of this study is to understand the effect of laser irradiance and interaction time on surface morphology configuration. An Nd:YAG laser system with TEM00 pulse processing mode was used to modify the samples. Metallographic study shows samples were analyzed for focal position effect on melted pool size, angle of peaks geometry and laser modified layer depth. Surface morphology were analyzed for surface roughness. Laser modified layer shows depth ranged between 42.22 and 420.12 μm. Angle of peak bulge was found to be increase with increasing peak power. The maximum roughness, Ra, achieved in modified H13 was 21.10 μm. These findings are significant to enhance surface properties of laser modified steel and cast iron for dies and high wear resistance applications.

  14. Surface modification to produce hydrophobic nano-silica particles using sodium dodecyl sulfate as a modifier

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Bing; Liang, Yong; Wang, Ting-Jie, E-mail: wangtj@tsinghua.edu.cn; Jiang, Yanping

    2016-02-28

    Graphical abstract: Nano silica particle was modified to produce hydrophobic surface with contact angle of 107° using the water soluble SDS as a modifier through a new route. The grafted density reached 1.82–2 nm. Brønsted acid sites supply proton to react with SDS via generating carbocation, forming a Si–O–C structure. - Highlights: • Silica was modified to produce hydrophobic surface using SDS as modifier. • The route is free of organic solvent and gets perfect contact of SDS and silica. • Contact angle of modified silica particles reached 107°. • Grafted density on the silica surface reached 1.82 SDS nm{sup −2}. • Brønsted acid sites supply proton to react with SDS via generating carbocation. - Abstract: Hydrophobic silica particles were prepared using the surfactant sodium dodecyl sulfate (SDS) as a modifier by a new route comprising three processes, namely, aqueous mixing, spray drying and thermal treatment. Since SDS dissolves in water, this route is free of an organic solvent and gave a perfect dispersion of SDS, that is, there was excellent contact between SDS and silica particles in the modification reaction. The hydrophobicity of the modified surface was verified by the contact angle of the nano-sized silica particles, which was 107°. The SDS grafting density reached 1.82 nm{sup −2}, which is near the highest value in the literature. The optimal parameters of the SDS/SiO{sub 2} ratio in the aqueous phase, process temperature and time of thermal treatment were determined to be 20%, 200 °C and 30 min, respectively. The grafting mechanism was studied by comparing the modification with that on same sized TiO{sub 2} particles, which indicated that the protons of the Brønsted acid sites on the surface of SiO{sub 2} reacted with SDS to give a carbocation which then formed a Si–O–C structure. This work showed that the hydrophilic surface of silica can be modified to be a hydrophobic surface by using a water soluble modifier SDS in a

  15. Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

    International Nuclear Information System (INIS)

    Susanto, H.; Roihatin, A.; Aryanti, N.; Anggoro, D.D.; Ulbricht, M.

    2012-01-01

    This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 ± 4.2 o to 37.8 ± 4.2 o to 42.5 ± 4.3 o depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: ► We compared different methods to prepare low fouling ultrafiltration (UF) membranes.

  16. Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

    Energy Technology Data Exchange (ETDEWEB)

    Susanto, H., E-mail: heru.susanto@undip.ac.id [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Roihatin, A.; Aryanti, N.; Anggoro, D.D. [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Ulbricht, M. [Lehrstuhl fuer Technische Chemie, Universitaet Duisburg-Essen, Germany, Universitaetstr. 5, Essen (Germany)

    2012-10-01

    This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 {+-} 4.2{sup o} to 37.8 {+-} 4.2{sup o} to 42.5 {+-} 4.3{sup o} depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: Black-Right-Pointing-Pointer We compared different methods to prepare low

  17. Formulation of a modified release metformin. HCl matrix tablet: influence of some hydrophilic polymers on release rate and in-vitro evaluation

    Directory of Open Access Journals (Sweden)

    John Rojas

    2011-09-01

    Full Text Available Metformin hydrochloride is an antidiabetic agent which improves glucose tolerance in patients with type 2 diabetes and reduces basal plasma levels of glucose. In this study, a simplex centroid experimental design with 69 runs was used to select the best combination of some hydrophilic polymers that rendered a 24 h in-vitro release profile of metformin.HCl. The Korsmeyer-Peppas model was used to model the dissolution profiles since it presented the best fit to the experimental data. Further, a cubic model predicted the best formulation of metformin.HCl containing polyvinyl pyrrolidone, ethyl cellulose, hydroxypropyl methyl cellulose, carrageenan, sodium alginate, and gum arabic at 6.26, 68.7, 6.26, 6.26, 6.26 and 6.26 % levels, respectively. The validation runs confirmed the accuracy of the cubic model with six components for predicting the best set of components which rendered a once-a-day modified release hydrophilic matrix tablet in compliance with the USP specifications.O cloridrato de metformina é um agente antidiabético que melhora a tolerância à glicose em pacientes com diabetes tipo 2 e reduz os níveis plasmáticos basais de glicose. Neste estudo, um projeto experimental do tipo "centróide simplex" com 69 tomadas foi usado para selecionar a melhor combinação de alguns polímeros hidrofílicos que gerou um perfil de liberação da metformina.HCl de 24 horas. O modelo Korsmeyer-Peppas foi usado para modelar os perfis de dissolução, uma vez que apresentou os melhores ajustes aos dados experimentais. Além disso, um modelo cúbico previu a melhor formulação de metformina.HCl sendo aquela contendo polivinilpirrolidona, etilcelulose, hidroxipropilmetil celulose, carragena, alginato de sódio e goma arábica nos níveis 6.26, 68.7, 6.26, 6.26, 6.26 e 6.26 %, respectivamente. As corridas de validação confirmaram a precisão do modelo cúbico com os seis componentes para prever o melhor conjunto de componentes que originou uma

  18. Surface Properties of PAN-based Carbon Fibers Modified by Electrochemical Oxidization in Organic Electrolyte Systems

    Directory of Open Access Journals (Sweden)

    WU Bo

    2016-09-01

    Full Text Available PAN-based carbon fibers were modified by electrochemical oxidization using fatty alcohol polyoxyethylene ether phosphate (O3P, triethanolamine (TEOA and fatty alcohol polyoxyethylene ether ammonium phosphate (O3PNH4 as organic electrolyte respectively. Titration analysis, single fiber fracture strength measurement and field emission scanning electron microscopy (FE-SEM were used to evaluate the content of acidic functional group on the surface, mechanical properties and surface morphology of carbon fiber. The optimum process of electrochemical treatment obtained is at 50℃ for 2min and O3PNH4 (5%, mass fraction as the electrolyte with current density of 2A/g. In addition, the surface properties of modified carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS and single fiber contact angle test. The results show that the hydrophilic acidic functional groups on the surface of carbon fiber which can enhance the surface energy are increased by the electrochemical oxidation using O3PNH4 as electrolyte, almost without any weakening to the mechanical properties of carbon fiber.

  19. Induced superhydrophobic and antimicrobial character of zinc metal modified ceramic wall tile surfaces

    Science.gov (United States)

    Özcan, Selçuk; Açıkbaş, Gökhan; Çalış Açıkbaş, Nurcan

    2018-04-01

    Hydrophobic surfaces are also known to have antimicrobial effect by restricting the adherence of microorganisms. However, ceramic products are produced by high temperature processes resulting in a hydrophilic surface. In this study, an industrial ceramic wall tile glaze composition was modified by the inclusion of metallic zinc powder in the glaze suspension applied on the pre-sintered wall tile bodies by spraying. The glazed tiles were gloss fired at industrially applicable peak temperatures ranging from 980 °C to 1100 °C. The fired tile surfaces were coated with a commercial fluoropolymer avoiding water absorption. The surfaces were characterized with SEM, EDS, XRD techniques, roughness, sessile water drop contact angle, surface energy measurements, and standard antimicrobial tests. The surface hydrophobicity and the antimicrobial activity results were compared with that of unmodified, uncoated gloss fired wall tiles. A superhydrophobic contact angle of 150° was achieved at 1000 °C peak temperature due to the formation of micro-structured nanocrystalline zinc oxide granules providing a specific surface topography. At higher peak temperatures the hydrophobicity was lost as the specific granular surface topography deteriorated with the conversion of zinc oxide granules to the ubiquitous willemite crystals embedded in the glassy matrix. The antimicrobial efficacy also correlated with the hydrophobic character.

  20. Modified Antifreeze Liquids for Use on Surfaces

    Science.gov (United States)

    Lynn, R. O.

    1983-01-01

    Report presents results of evaluation of two antifreeze liquids, dimethyl sulfoxide and ethylene glycol and five viscosity modifiers: gelatin, gum tragacanth, starch, agarose powder and citrus pectin. Purpose of evaluation to find best way of dealing with frost formation on Space Shuttle.

  1. Modifying glass surfaces via internal diffusion

    DEFF Research Database (Denmark)

    Smedskjaer, M.M.; Yue, Y.Z.; Deubener, J.

    2010-01-01

    leads to outward diffusion (OD) of divalent cations (primarily Mg2+), i.e., diffusion from the interior of the glass to the surface, and thereby, to formation of an oxide surface nano-layer. in contrast, when the glasses are heat-treated in H-2/N-2 gas containing 10 vol.% H-2, reduction of Fe3+ to Fe2...... on some properties such as hardness, chemical durability, and surface wettability....

  2. Hybrid selective surface hydrophilization and froth flotation separation of hazardous chlorinated plastics from E-waste with novel nanoscale metallic calcium composite

    Energy Technology Data Exchange (ETDEWEB)

    Mallampati, Srinivasa Reddy, E-mail: srireddys@ulsan.ac.kr; Heo, Je Haeng; Park, Min Hee

    2016-04-05

    Highlights: • Nanometallic Ca/CaO treatment significantly enhanced PVC surface hydrophilicity. • The contact angle of PVC significantly decreased compared to other E-waste plastics. • 100% of PVC was selectively separated with 96.4% purity from E-waste plastics. • SEM/XPS results indicated an oxidative degradation of chlorides on the PVC surface. • Hybrid treatment with nanometallic Ca/CaO and froth flotation is effective. - Abstract: Treatment by a nanometallic Ca/CaO composite has been found to selectively hydrophilize the surface of polyvinyl chloride (PVC), enhancing its wettability and thereby promoting its separation from E-waste plastics by means of froth flotation. The treatment considerably decreased the water contact angle of PVC, by about 18°. The SEM images of the PVC plastic after treatment displayed significant changes in their surface morphology compared to other plastics. The SEM-EDS results reveal that a markedly decrease of [Cl] concentration simultaneously with dramatic increase of [O] on the surface of the PCV samples. XPS results further confirmed an increase of hydrophilic functional groups on the PVC surface. Froth flotation at 100 rpm mixing speed was found to be optimal, separating 100% of the PVC into a settled fraction of 96.4% purity even when the plastics fed into the reactor were of nonuniform size and shape. The total recovery of PVC-free plastics in E-waste reached nearly 100% in the floated fraction, significantly improved from the 20.5 wt% of light plastics that can be recovered by means of conventional wet gravity separation. The hybrid method of nanometallic Ca/CaO treatment and froth flotation is effective in the separation of hazardous chlorinated plastics from E-waste plastics.

  3. Hybrid selective surface hydrophilization and froth flotation separation of hazardous chlorinated plastics from E-waste with novel nanoscale metallic calcium composite

    International Nuclear Information System (INIS)

    Mallampati, Srinivasa Reddy; Heo, Je Haeng; Park, Min Hee

    2016-01-01

    Highlights: • Nanometallic Ca/CaO treatment significantly enhanced PVC surface hydrophilicity. • The contact angle of PVC significantly decreased compared to other E-waste plastics. • 100% of PVC was selectively separated with 96.4% purity from E-waste plastics. • SEM/XPS results indicated an oxidative degradation of chlorides on the PVC surface. • Hybrid treatment with nanometallic Ca/CaO and froth flotation is effective. - Abstract: Treatment by a nanometallic Ca/CaO composite has been found to selectively hydrophilize the surface of polyvinyl chloride (PVC), enhancing its wettability and thereby promoting its separation from E-waste plastics by means of froth flotation. The treatment considerably decreased the water contact angle of PVC, by about 18°. The SEM images of the PVC plastic after treatment displayed significant changes in their surface morphology compared to other plastics. The SEM-EDS results reveal that a markedly decrease of [Cl] concentration simultaneously with dramatic increase of [O] on the surface of the PCV samples. XPS results further confirmed an increase of hydrophilic functional groups on the PVC surface. Froth flotation at 100 rpm mixing speed was found to be optimal, separating 100% of the PVC into a settled fraction of 96.4% purity even when the plastics fed into the reactor were of nonuniform size and shape. The total recovery of PVC-free plastics in E-waste reached nearly 100% in the floated fraction, significantly improved from the 20.5 wt% of light plastics that can be recovered by means of conventional wet gravity separation. The hybrid method of nanometallic Ca/CaO treatment and froth flotation is effective in the separation of hazardous chlorinated plastics from E-waste plastics.

  4. Osteoblast cell response to surface-modified carbon nanotubes

    International Nuclear Information System (INIS)

    Zhang Faming; Weidmann, Arne; Nebe, J. Barbara; Burkel, Eberhard

    2012-01-01

    In order to investigate the interaction of cells with modified multi-walled carbon nanotubes (MWCNTs) for their potential biomedical applications, the MWCNTs were chemically modified with carboxylic acid groups (–COOH), polyvinyl alcohol (PVA) polymer and biomimetic apatite on their surfaces. Additionally, human osteoblast MG-63 cells were cultured in the presence of the surface-modified MWCNTs. The metabolic activities of osteoblastic cells, cell proliferation properties, as well as cell morphology were studied. The surface modification of MWCNTs with biomimetic apatite exhibited a significant increase in the cell viability of osteoblasts, up to 67.23%. In the proliferation phases, there were many more cells in the biomimetic apatite-modified MWCNT samples than in the MWCNTs–COOH. There were no obvious changes in cell morphology in osteoblastic MG-63 cells cultured in the presence of these chemically-modified MWCNTs. The surface modification of MWCNTs with apatite achieves an effective enhancement of their biocompatibility.

  5. Effect of the hydrophilic block length on the surface-active and micellar thermodynamic properties of oxyethylene-oxybutylene diblock copolymers in aqueous solution

    International Nuclear Information System (INIS)

    Khan, A.; Usman, M.; Siddiq, M.; Fatima, G.; Harrison, W.

    2009-01-01

    The effect of hydrophilic block length on the surface and micellar thermodynamic properties of aqueous solution of E/sub 40/B/sub 8/, E/sub 80/B/sub 8/ and E/sub 120/B/sub 8/ diblock copolymers, were studied by surface tension measurements over a wide concentration and temperature range; where E stands for an oxyethylene unit and B for an oxybutylene unit. Like conventional surfactants, two breaks (change in the slope) were observed in the surface tension vs logarithm of concentration curve for all the three copolymers. Surface tension measurements were used to estimate surface excess concentrations (r m), area per molecule at air/water interface a and thermodynamic parameters for all adsorption of the pre-micellar region in the temperature range 20 to 50 degree C. Likewise the critical micelle concentration, CMC and thermodynamic parameters for micellization were also calculated for the post-micellar solutions at all temperatures. For comparison the thermodynamic parameters of adsorption and micellization are discussed in detail. The impact of varying E-block length and temperature on all calculated parameters are also discussed. This study shows the importance of hydrophobic-hydrophilic-balance (HHB) of copolymers on various surface and micellar properties. (author)

  6. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Huihui; Qian, Bin; Zhang, Wei [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); Lan, Minbo, E-mail: minbolan@ecust.edu.cn [Shanghai Key Laboratory of Functional Materials Chemistry and Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-02-15

    Highlights: • Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP. • The effect of polymerization time on surface property and topography was studied. • Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted. • Competitive adsorption of three proteins on PVP–PU films was evaluated. - Abstract: An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU–PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU–PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU–PVP (6.0 h) film reduced greatly to 0.08 μg/cm{sup 2}, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  7. Protein adsorption resistance of PVP-modified polyurethane film prepared by surface-initiated atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Yuan, Huihui; Qian, Bin; Zhang, Wei; Lan, Minbo

    2016-01-01

    Highlights: • Antifouling PVP brushes were successfully grafted on PU films by SI-ATRP. • The effect of polymerization time on surface property and topography was studied. • Hydrophilicity and protein fouling resistance of PVP–PU films were greatly promoted. • Competitive adsorption of three proteins on PVP–PU films was evaluated. - Abstract: An anti-fouling surface of polyurethane (PU) film grafted with Poly(N-vinylpyrrolidone) (PVP) was prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). And the polymerization time was investigated to obtain PU films with PVP brushes of different lengths. The surface properties and protein adsorption of modified PU films were evaluated. The results showed that the hydrophilicity of PU–PVP films were improved with the increase of polymerization time, which was not positive correlation with the surface roughness due to the brush structure. Additionally, the protein resistance performance was promoted when prolonging the polymerization time. The best antifouling PU–PVP (6.0 h) film reduced the adsoption level of bovine serum albumin (BSA), lysozyme (LYS), and brovin serum fibrinogen (BFG) by 93.4%, 68.3%, 85.6%, respectively, compared to the unmodified PU film. The competitive adsorption of three proteins indicated that LYS preferentially adsorbed on the modified PU film, while BFG had the lowest adsorption selectivity. And the amount of BFG on PU–PVP (6.0 h) film reduced greatly to 0.08 μg/cm"2, which was almost one-tenth of its adsorption from the single-protein system. Presented results suggested that both hydrophilicity and surface roughness might be the important factors in all cases of protein adsorption, and the competitive or selective adsorption might be related to the size of the proteins, especially on the non-charged films.

  8. Tribologically modified surfaces on elastomeric materials

    NARCIS (Netherlands)

    Rodriguez, N.V.; Masen, Marc Arthur; Schipper, Dirk J.

    2013-01-01

    As the result of tribological loading, the properties of the surface of elastomeric materials will alter. This effect has been observed using SEM and EDS analysis of the tread of a used car tyre, where differences in structure between the substrate and the area near the surface were found. To study

  9. Surface modifying method for metal member

    International Nuclear Information System (INIS)

    Amano, Kazuo; Enomoto, Kunio; Hirano, Akihiko; Hirano, Atsuya; Hattori, Shigeo; Hayashi, Eisaku; Ueyama, Toshiharu; Hayashi, Makoto

    1998-01-01

    A surface of a metal member such as carbon steel to be used in a corrosion circumstance such as in a nuclear power plant and a thermoelectric plant are polished. A printing method is conducted for removing obstacles on the surface of the member. Namely, a photographing printing paper immersed in a diluted sulfuric acid solution is appended tightly to the portion with its surface polished smoothly. Sulfur present in the form of an obstacle of MnS or present alone in the material reacts with the sulfuric acid to form a sulfuric acid gas, and reacts with Ag of the printing paper to discolor the printing paper to brown. When a peeled printing paper is discolored to brown, sulfur printing is repeated. After conforming that the peeled printing paper is white, the surface is washed. Subsequently, surface plasticization is conducted by water jet peening or shot peening. (I.N.)

  10. Surface-modified polymeric pads for enhanced performance during chemical mechanical planarization

    International Nuclear Information System (INIS)

    Deshpande, S.; Dakshinamurthy, S.; Kuiry, S.C.; Vaidyanathan, R.; Obeng, Y.S.; Seal, S.

    2005-01-01

    The chemical mechanical planarization (CMP) process occurs at an atomic level at the slurry/wafer interface and hence slurries and polishing pads play a critical role in their successful implementation. Polyurethane is a commonly used polymer in the manufacturing of CMP pads. These pads are incompatible with some chemicals present in the CMP slurries, such as hydrogen peroxide. To overcome these problems, Psiloquest has developed new Application Specific Pads (ASP). Surface of such pads has been modified by depositing a thin film of tetraethyl orthosilicate using plasma-enhanced chemical vapor deposition (PECVD) process. In the present study, mechanical properties of such coated pads have been investigated using nanoindentation. The surface morphology and the chemistry of the ASP were studied using scanning electron microcopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy techniques. It was observed that mechanical and chemical properties of the pad top surface are a function of the PECVD coating time. Such PECVD-treated pads are found to be hydrophilic and do not require storage in aqueous media during the not-in-use period. The metal removal rate using such surface-modified polishing pads was found to increase linearly with the PECVD coating time

  11. Antibacterial effect of silver nanofilm modified stainless steel surface

    Science.gov (United States)

    Fang, F.; Kennedy, J.; Dhillon, M.; Flint, S.

    2015-03-01

    Bacteria can attach to stainless steel surfaces, resulting in the colonization of the surface known as biofilms. The release of bacteria from biofilms can cause contamination of food such as dairy products in manufacturing plants. This study aimed to modify stainless steel surfaces with silver nanofilms and to examine the antibacterial effectiveness of the modified surface. Ion implantation was applied to produce silver nanofilms on stainless steel surfaces. 35 keV Ag ions were implanted with various fluences of 1 × 1015 to 1 × 1017 ions•cm-2 at room temperature. Representative atomic force microscopy characterizations of the modified stainless steel are presented. Rutherford backscattering spectrometry spectra revealed the implanted atoms were located in the near-surface region. Both unmodified and modified stainless steel coupons were then exposed to two types of bacteria, Pseudomonas fluorescens and Streptococcus thermophilus, to determine the effect of the surface modification on bacterial attachment and biofilm development. The silver modified coupon surface fluoresced red over most of the surface area implying that most bacteria on coupon surface were dead. This study indicates that the silver nanofilm fabricated by the ion implantation method is a promising way of reducing the attachment of bacteria and delay biofilm formation.

  12. Polar silica-based stationary phases. Part II- Neutral silica stationary phases with surface bound maltose and sorbitol for hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Rathnasekara, Renuka; El Rassi, Ziad

    2017-07-28

    Two neutral polyhydroxylated silica bonded stationary phases, namely maltose-silica (MALT-silica) and sorbitol-silica (SOR-silica), have been introduced and chromatographically characterized in hydrophilic interaction liquid chromatography (HILIC) for a wide range of polar compounds. The bonding of the maltose and sorbitol to the silica surface was brought about by first converting bare silica to an epoxy-activated silica surface via reaction with γ-glycidoxypropyltrimethoxysilane (GPTMS) followed by attaching maltose and sorbitol to the epoxy surface in the presence of the Lewis acid catalyst BF 3 .ethereate. Both silica based columns offered the expected retention characteristics usually encountered for neutral polar surface. The retention mechanism is majorly based on solute' differential partitioning between an organic rich hydro-organic mobile phase (e.g., ACN rich mobile phase) and an adsorbed water layer on the surface of the stationary phase although additional hydrogen bonding was also responsible in some cases for solute retention. The MALT-silica column proved to be more hydrophilic and offered higher retention, separation efficiency and resolution than the SOR-silica column among the tested polar solutes such as derivatized mono- and oligosaccharides, weak phenolic acids, cyclic nucleotide monophosphate and nucleotide-5'-monophosphates, and weak bases, e.g., nucleobases and nucleosides. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Surface modified nano-hydroxyapatite/poly(lactide acid) composite and its osteocyte compatibility

    International Nuclear Information System (INIS)

    Diao Huaxin; Si Yunfeng; Zhu Aiping; Ji Lijun; Shi Hongchan

    2012-01-01

    In this study, melt blending was used to fabricate poly(lactic acid) (PLA)/ hydroxyapatite (HA) nanocomposites. Surface modifying HA nanoparticles (mHA) with dodecyl alcohol through esterification reaction could effectively improve the dispersibility of HA nanoparticles in PLA matrix and the interfacial interactions between PLA and HA nanoparticles, as revealed by field emission scanning electron microscopy (FESEM), rheology analysis, and dynamic mechanical thermal analysis (DMTA). mHA/PLA nanocomposite film demonstrated better cartilage cell attachment, spreading and proliferation than that of PLA and HA/PLA film. The good cytocompatibility could be due to the good dispersibility of the osteoinductive HA nanoparticles, good interfacial interactions between PLA and HA nanoparticles, and balanced hydrophobic/hydrophilic property. This newly developed mHA/PLA nanocomposites may be considered for bone tissue engineering applications. - Highlights: ► Dodecyl alcohol modifies HA nanoparticles via esterification reaction. ► The modified HA results in good dispersibility in PLA matrix. ► The interfacial interactions are improved because of the modified HA. ► The addition of HA and mHA results in good cell affinity and biocompatibility.

  14. Polydopamine/Cysteine surface modified isoporous membranes with self-cleaning properties

    KAUST Repository

    Shevate, Rahul

    2017-02-03

    The major challenge in membrane filtration is fouling which reduces the membrane performance. Fouling is mainly due to the adhesion of foulants on the membrane surfaces. In this work, we studied the fouling behaviour of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) isoporous membrane and the mussel inspired polydopamine/L-cysteine isoporous zwitterionic membrane. Polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) isoporous membranes were fabricated via self-assembly and non-solvent induced phase separation method. Subsequently, the isoporous membrane was modified by a mild mussel-inspired polydopamine (PDA) coating; the isoporous surface structure and the water flux was retained. Zwitterionic L-cysteine was further anchored on the PDA coated membranes via Michael addition reaction at pH 7 and 50 °C to alleviate their antifouling ability with foulants solution. The membranes were thoroughly characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and zeta potential measurements. Contact angle and dynamic scanning calorimetry (DSC) measurements were carried out to examine the hydrophilicity. The pH-responsive behaviour of the modified membrane remains unchanged and antifouling ability after PDA/L-cysteine functionalization was improved. The modified and unmodified isoporous membranes were tested using humic acid and natural organic matter model solutions at 0.5 bar feed pressure.

  15. A modified stanton number for heat transfer through fabric surface

    Directory of Open Access Journals (Sweden)

    Zhang Shen-Zhong

    2015-01-01

    Full Text Available The Stanton number was originally proposed for describing heat transfer through a smooth surface. A modified one is suggested in this paper to take into account non-smooth surface or fractal surface. The emphasis is put on the heat transfer through fabrics.

  16. Ammonia synthesis on Au modified Fe(111) and Ag and Cu modified Fe(100) surfaces

    DEFF Research Database (Denmark)

    Lytken, Ole; Waltenburg, Hanne Neergaard; Chorkendorff, Ib

    2003-01-01

    In order to investigate any influence of steps and possible positive effects of making surface alloys the ammonia synthesis has been investigated over Au modified Fe(111) and Ag and Cu modified Fe(100) single crystals in the temperature range 603-773 K, using a system combining ultra-high vacuum...... and a high-pressure cell. Ammonia was synthesized from a stoichiometric (N-2:3H(2)) gas mixture at a pressure of 2 bar. By deposition of small amounts of An, the ammonia production activity of the Fe(1 1 1) surface can be enhanced. More important, for the gold modified surface, the reaction order in ammonia...

  17. Hydrophilization of graphite using plasma above/in a solution

    Science.gov (United States)

    Hoshino, Shuhei; Kawahara, Kazuma; Takeuchi, Nozomi

    2018-01-01

    A hydrophilization method for graphite is required for applications such as conductive ink. In typical chemical oxidation methods for graphite have the problems of producing many defects in graphite and a large environmental impact. In recent years, the plasma treatment has attracted attention because of the high quality of the treated samples and the low environmental impact. In this study, we proposed an above-solution plasma treatment with a high contact probability of graphite and plasma since graphite accumulates on the solution surface due to its hydrophobicity, which we compared with a so-called solution plasma treatment. Graphite was hydrophilized via reactions with OH radicals generated by the plasma. It was confirmed that hydroxyl and carboxyl groups were modified to the graphite and the dispersibility was improved. The above-solution plasma achieved more energy-efficient hydrophilization than the solution plasma and it was possible to enhance the dispersibility by increasing the plasma-solution contact area.

  18. Hybrid selective surface hydrophilization and froth flotation separation of hazardous chlorinated plastics from E-waste with novel nanoscale metallic calcium composite.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Heo, Je Haeng; Park, Min Hee

    2016-04-05

    Treatment by a nanometallic Ca/CaO composite has been found to selectively hydrophilize the surface of polyvinyl chloride (PVC), enhancing its wettability and thereby promoting its separation from E-waste plastics by means of froth flotation. The treatment considerably decreased the water contact angle of PVC, by about 18°. The SEM images of the PVC plastic after treatment displayed significant changes in their surface morphology compared to other plastics. The SEM-EDS results reveal that a markedly decrease of [Cl] concentration simultaneously with dramatic increase of [O] on the surface of the PCV samples. XPS results further confirmed an increase of hydrophilic functional groups on the PVC surface. Froth flotation at 100rpm mixing speed was found to be optimal, separating 100% of the PVC into a settled fraction of 96.4% purity even when the plastics fed into the reactor were of nonuniform size and shape. The total recovery of PVC-free plastics in E-waste reached nearly 100% in the floated fraction, significantly improved from the 20.5wt% of light plastics that can be recovered by means of conventional wet gravity separation. The hybrid method of nanometallic Ca/CaO treatment and froth flotation is effective in the separation of hazardous chlorinated plastics from E-waste plastics. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Cytokine Adsorption onto the Modified Carbon Sorbent Surface in vitro in Peritonitis

    Directory of Open Access Journals (Sweden)

    T. I. Dolgikh

    2009-01-01

    Full Text Available Objective: to evaluate the efficiency of cytokine sorption with carbon with a locally aminocaproic acid-modified surface from the plasma of patients with general purulent peritonitis. Materials and methods. The material of the investigation was the plasma obtained during plasmapheresis in 10 patients with acute pancreatitis complicated by pancreonecrosis and general purulent peritonitis, which was used to estimate before and after sorption the content of the cytokines: interleukin (IL-1/8, IL-4, and IL-8 by enzyme immunoassay. The sorption properties of carbon hemosor-bent and aminocaproic acid-modified sorbent were comparatively evaluated. Results. Aminocaproic acid-induced modification of the carbon adsorbent surface with its further polycondensation results in the higher content of superficial functional groups (oxygen- and nitrogen-containing that enhance the hydrophility of the surface and the specific pattern of sorption, thus acting as a means for controlling and regulating the plasma concentration of regulatory proteins, primarily the proinflammatory cytokine IL-1^3, the chemokine IL-8 and the T-helper cell clone cytokine IL-4.

  20. A directional entrapment modification on the polyethylene surface by the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether

    Science.gov (United States)

    Lu, Qiang; Chen, Yi; Huang, Juexin; Huang, Jian; Wang, Xiaolin; Yao, Jiaying

    2018-05-01

    A novel entrapment modification method involving directional implantation of the amphiphilic modifier of stearyl-alcohol poly(ethylene oxide) ether (AEO) into the high-density polyethylene (HDPE) surface is proposed. This modification technique allows the AEO modifier to be able to spontaneously attain and subsequently penetrate into the swollen HDPE surface with its hydrophobic stearyl segment, while its hydrophilic poly(ethylene oxide) (PEO) segment spontaneously points to water. The AEO modifier with a HLB number below 8.7 was proved appropriate for the directional entrapment, Nevertheless, AEOs with larger HLB numbers were also effective modifiers in the presence of salt additives. In addition, a larger and hydrophobic micelle, induced respectively by the AEO concentration above 1.3 × 10-2 mol/L and the entrapping temperature above the cloud point of AEO, could lead to a sharp contact angle decline of the modified surface. Finally, a hydrophilic HDPE surface with the modifier coverage of 38.9% was reached by the directional entrapment method, which is far larger than that of 19.2% by the traditional entrapment method.

  1. Atomic diffusion in laser surface modified AISI H13 steel

    Science.gov (United States)

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

    2013-07-01

    This paper presents a laser surface modification process of AISI H13 steel using 0.09 and 0.4 mm of laser spot sizes with an aim to increase surface hardness and investigate elements diffusion in laser modified surface. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, pulse repetition frequency (PRF), and overlap percentage. The hardness properties were tested at 981 mN force. Metallographic study and energy dispersive X-ray spectroscopy (EDXS) were performed to observe presence of elements and their distribution in the sample surface. Maximum hardness achieved in the modified surface was 1017 HV0.1. Change of elements composition in the modified layer region was detected in the laser modified samples. Diffusion possibly occurred for C, Cr, Cu, Ni, and S elements. The potential found for increase in surface hardness represents an important method to sustain tooling life. The EDXS findings signify understanding of processing parameters effect on the modified surface composition.

  2. Surface-modified multifunctional MIP nanoparticles

    Science.gov (United States)

    Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

    2013-04-01

    The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity

  3. Pure and Nb2O5-doped TiO2 amorphous thin films grown by dc magnetron sputtering at room temperature: Surface and photo-induced hydrophilic conversion studies

    International Nuclear Information System (INIS)

    Suchea, M.; Christoulakis, S.; Tudose, I.V.; Vernardou, D.; Lygeraki, M.I.; Anastasiadis, S.H.; Kitsopoulos, T.; Kiriakidis, G.

    2007-01-01

    Photo-induced hydrophilicity of titanium dioxide makes this material one of the most suitable for various coating applications in antifogging mirrors and self-cleaning glasses. The field of functional titanium dioxide coatings is expanding rapidly not only in applications for glass but also in applications for polymer, metal and ceramic materials. The high hydrophilic surface of TiO 2 is interesting for understanding also the basic photon-related surface science of titanium dioxide. In doing so, it is inevitably necessary to understand the relationship between the photoreaction and the surface properties. In this work, photo-induced hydrophilic conversion was evaluated on amorphous pure and niobium oxide-doped titanium dioxide thin films on Corning 1737F glass grown by dc magnetron sputtering technique at room temperature. This study is focused on the influence of the Ar:O ratio during sputtering plasma deposition on thin film surface morphology and subsequent photo-induced hydrophilic conversion results. Structural characterization carried out by X-ray diffraction and atomic force microscopy (AFM) has shown that our films are amorphous and extremely smooth with a surface roughness bellow 1 nm. Contact angle measurements were performed on as-deposited and during/after 10 min UV exposure. We present evidence that the photo-induced hydrophilic conversion of film surface is directly correlated with surface morphology and can be controlled by growth conditions

  4. Surface treated fly ash filled modified epoxy composites

    Directory of Open Access Journals (Sweden)

    Uma Dharmalingam

    2015-01-01

    Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

  5. Hydrophobicity of electron beam modified surface of hydroxyapatite films

    Energy Technology Data Exchange (ETDEWEB)

    Gregor, M., E-mail: gregor@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Plecenik, T. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Tofail, S.A.M. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Zahoran, M.; Truchly, M. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Vargova, M. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Laffir, F. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Plesch, G. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Kus, P.; Plecenik, A. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia)

    2015-05-15

    Highlights: • Surface potential of hydroxyapatite films were modified by focused electron beam. • Micron-sized domains of modified surface potential were created. • Wettability and surface free energy of the irradiated areas was studied. • Possible mechanisms of increased surface hydrophobicity are discussed. - Abstract: Arrays of micron-sized domains of modified surface potential were created on hydroxyapatite films by mid-energy (20 keV) electron beam irradiation available in a laboratory scanning electron microscope. The dosage of electron beam was varied between 10{sup −3} and 10{sup 3} μC/cm{sup 2} to inject charge into the film surface. Contrary to the conventional electrowetting theory, the dosage of injected charge used in creating such microdomains caused a gradual increase of the water contact angle from 57° to 93° due to the elimination of the polar component of the surface free energy. Surface contamination by carbonaceous species can be held only partially responsible for such behavior at lower dosage of electron beam. A transfer of free surface charge to water and an electron beam induced disruption of polar orientation of OH ions have been attributed to be influencial factors in the overall dewetting behavior.

  6. The PM2.5 capture of poly (lactic acid)/nano MOFs eletrospinning membrane with hydrophilic surface

    Science.gov (United States)

    Wang, Yating; Dai, Xiu; Li, Xu; Wang, Xinlong

    2018-03-01

    In this article, metal organic frameworks (MOFs) material is introduced in the poly (lactic acid) (PLA) by electrospinning to fabricate the nanocomposite membrane. The acrylic acid (AA) is grafted onto the membrane under UV light. The prepared membrane is studied by scanning electron microscopy (SEM), x-ray diffraction (XRD), thermogravimetry (TG), contact angle test and tensile strength test. The SEM image and XRD indicate that nano MOFs particles adhere to the membrane. Contact angle test shows that grafting AA on the composite fiber membrane improves its hydrophilicity effectively. TG analyses show that the particulate matter (PM) capture capacity of PLA membrane with 2 wt% ZIF-8 content is 22%, which rises to 37% after grafting.

  7. Development and evaluation of targeting ligands surface modified paclitaxel nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Jeong Sun [Division of Undeclared Majors, Chosun University, Gwangju 501-759 (Korea, Republic of); Yoon, Doo-Soo; Sohn, Jun Youn [Department of Bioenvironmental & Chemical Engineering, Chosun College of Science & Technology, Gwangju 501-744 (Korea, Republic of); Park, Jeong-Sook, E-mail: eicosa@cnu.ac.kr [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Choi, Jin-Seok, E-mail: c34281@gmail.com [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of)

    2017-03-01

    To overcome the toxicity of excipient or blank nanoparticles for drug delivery nano-system, the surface modified paclitaxel nanocrystals (PTX-NC) have been developed. PTX-NCs were prepared by nano-precipitation method. The surface of PTX-NCs were modified by grafting with apo-transferrin (Tf) or hyaluronic acid (HA). The physical properties of PTX-NCs were evaluated by field emission scanning electron microscope (FE-SEM), zeta-sizer, zeta-potential, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectrometry. In vitro drug release study was performed in phosphate buffered saline (PBS) with or without 0.5% (w/v) Tween 80 for 24 h. Cellular uptake was studied at time intervals of 0.5, 1, and 2 h in MCF-7 cells, and cell growth inhibition study was performed for 24 h using MCF-7 cells (cancer cells), and HaCaT cells (normal cells). Three different types of PTX-NCs with a mean size of 236.0 ± 100.6 nm (PTX-NC), 302.0 ± 152.0 nm (Tf-PTX-NC) and 339 ± 180.6 nm (HA-PTX-NC) were successfully prepared. The drug release profiles showed 29.1%/6.9% (PTX (pure)), 40.7%/23.9% (PTX-NC), 50.5%/25.1% (Tf-PTX-NC) and 46.8/24.8% (HA-PTX-NC) in PBS with/without 0.5% (w/v) Tween 80 for 24 h, respectively. As per the results, the drug release of PTX-NCs showed the faster release as compared to that of PTX (pure). Surface modified PTX-NCs exhibited higher values for cell permeability than unmodified PTX-NC in the cellular uptake study. Surface modified PTX-NCs inhibited the cell growth approximately to 60% in MCF-7 cells, however effect of surface modified PTX-NCs on normal cell line was lower than the PTX-NC and PTX (pure). In conclusion, biological macromolecules (Tf or HA) surface modified PTX-NC enhanced the cellular uptake and the cell growth inhibition. - Highlights: • Surface modified PTX-NCs with HA and Tf are successfully prepared by adsorption method. • Enhanced cellular uptake of modified PTX-NCs compared to unmodified PTX-NC • Improved

  8. Characteristics of modified martensitic stainless steel surfaces under tribocorrosion conditions

    International Nuclear Information System (INIS)

    Rozing, Goran; Marusic, Vlatko; Alar, Vesna

    2017-01-01

    Stainless steel samples were tested in the laboratory and under real conditions of tribocorrosion wear. Electrochemical tests were also carried out to verify the corrosion resistance of modified steel surfaces. Metallographic analysis and hardness testing were conducted on stainless steel samples X20Cr13 and X17CrNi16 2. The possibilities of applications of modified surfaces of the selected steels were investigated by testing the samples under real wear conditions. The results have shown that the induction hardened and subsequently nitrided martensitic steels achieved an average wear resistance of up to three orders of magnitude higher as compared to the delivered condition.

  9. Characteristics of modified martensitic stainless steel surfaces under tribocorrosion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rozing, Goran [Osijek Univ. (Croatia). Chair of Mechanical Engineering; Marusic, Vlatko [Osijek Univ. (Croatia). Dept. of Engineering Materials; Alar, Vesna [Zagreb Univ. (Croatia). Dept. Materials

    2017-04-01

    Stainless steel samples were tested in the laboratory and under real conditions of tribocorrosion wear. Electrochemical tests were also carried out to verify the corrosion resistance of modified steel surfaces. Metallographic analysis and hardness testing were conducted on stainless steel samples X20Cr13 and X17CrNi16 2. The possibilities of applications of modified surfaces of the selected steels were investigated by testing the samples under real wear conditions. The results have shown that the induction hardened and subsequently nitrided martensitic steels achieved an average wear resistance of up to three orders of magnitude higher as compared to the delivered condition.

  10. Modifying surface resistivity and liquid moisture management property of keratin fibers through thiol-ene click reactions.

    Science.gov (United States)

    Yu, Dan; Cai, Jackie Y; Church, Jeffrey S; Wang, Lijing

    2014-01-22

    This paper reports on a new method for improving the antistatic and liquid moisture management properties of keratinous materials. The method involves the generation of thiols by controlled reduction of cystine disulfide bonds in keratin with tris(2-carboxyethyl) phosphine hydrochloride and subsequent grafting of hydrophilic groups onto the reduced keratin by reaction with an acrylate sulfonate or acrylamide sulfonate through thiol-ene click chemistry. The modified substrates were characterized with Raman spectroscopy and scanning electron microscopy and evaluated for their performance changes in liquid moisture management, surface resistivity, and wet burst strength. The results have revealed that the thiol-acrylate reaction is more efficient than the thiol-acrylamide reaction, and the keratinous substrate modified with an acrylate sulfonate salt exhibits significantly improved antistatic and liquid moisture management properties.

  11. Adhesive and morphological characteristics of surface chemically modified polytetrafluoroethylene films

    International Nuclear Information System (INIS)

    Hopp, B.; Kresz, N.; Kokavecz, J.; Smausz, T.; Schieferdecker, H.; Doering, A.; Marti, O.; Bor, Z.

    2004-01-01

    In the present paper, we report an experimental determination of adhesive and topographic characteristics of chemically modified surface of polytetrafluoroethylene (PTFE) films. The surface chemistry was modified by ArF excimer laser irradiation in presence of triethylene-tetramine photoreagent. The applied laser fluence was varied in the range of 0.4-9 mJ/cm 2 , and the number of laser pulses incident on the same area was 1500. To detect the changes in the adhesive features of the treated Teflon samples, we measured receding contact angle for distilled water and adhesion strength, respectively. It was found that the receding contact angle decreased from 96 deg. to 30-37 deg. and the adhesion strength of two-component epoxy glue to the treated sample surface increased from 0.03 to 9 MPa in the applied laser fluence range. Additionally, it was demonstrated that the adhesion of human cells to the modified Teflon samples is far better than to the untreated ones. The contact mode and pulsed force mode atomic force microscopic investigations of the treated samples demonstrated that the measured effective contact area of the irradiated films does not differ significantly from that of the original films, but the derived adhesion force is stronger on the modified samples than on the untreated ones. Hence, the increased adhesion of the treated Teflon films is caused by the higher surface energy

  12. Surface-modified magnetic nanoparticles for cell labeling

    Czech Academy of Sciences Publication Activity Database

    Zasońska, Beata Anna; Patsula, Vitalii; Stoika, R.; Horák, Daniel

    2014-01-01

    Roč. 13, č. 4 (2014), s. 63-73 ISSN 2305-7815 R&D Projects: GA MŠk(CZ) LH14318 Institutional support: RVO:61389013 Keywords : magnetic nanoparticles * surface-modified * cell labeling Subject RIV: CD - Macromolecular Chemistry

  13. Listeria monocytogenes repellence by enzymatically modified PES surfaces

    NARCIS (Netherlands)

    Veen, van der S.; Nady, N.; Franssen, M.C.R.; Zuilhof, H.; Boom, R.M.; Abee, T.; Schroën, C.G.P.H.

    2015-01-01

    : The effect of enzyme-catalyzed modification of poly(ethersulfone) (PES) on the adhesion and biofilm formation of two Listeria monocytogenes strains is evaluated under static and dynamic flow conditions. PES has been modified with gallic acid, ferulic acid and 4-hydroxybenzoic acid. The surfaces

  14. Hierarchical micro-nano structured Ti6Al4V surface topography via two-step etching process for enhanced hydrophilicity and osteoblastic responses

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Byeong-Seok; Kim, Sungwon; Kim, Hyoun-Ee; Jang, Tae-Sik, E-mail: cgamja@snu.ac.kr

    2017-04-01

    technique onto SLA-treated surface. • The MNH surface structure remarkably improved the hydrophilicity of Ti6Al4V-ELI. • The MNH surface exhibited good cell adhesion morphology and the highest value of the proliferation level. • A bone-to-implant contact area and new bone volume were significantly improved on the MNH surface structured screw.

  15. Hierarchical micro-nano structured Ti6Al4V surface topography via two-step etching process for enhanced hydrophilicity and osteoblastic responses

    International Nuclear Information System (INIS)

    Moon, Byeong-Seok; Kim, Sungwon; Kim, Hyoun-Ee; Jang, Tae-Sik

    2017-01-01

    technique onto SLA-treated surface. • The MNH surface structure remarkably improved the hydrophilicity of Ti6Al4V-ELI. • The MNH surface exhibited good cell adhesion morphology and the highest value of the proliferation level. • A bone-to-implant contact area and new bone volume were significantly improved on the MNH surface structured screw.

  16. ELECTROCATALYSIS ON SURFACES MODIFIED BY METAL MONOLAYERS DEPOSITED AT UNDERPOTENTIALS.

    Energy Technology Data Exchange (ETDEWEB)

    ADZIC,R.

    2000-12-01

    The remarkable catalytic properties of electrode surfaces modified by monolayer amounts of metal adatoms obtained by underpotential deposition (UPD) have been the subject of a large number of studies during the last couple of decades. This interest stems from the possibility of implementing strictly surface modifications of electrocatalysts in an elegant, well-controlled way, and these bi-metallic surfaces can serve as models for the design of new catalysts. In addition, some of these systems may have potential for practical applications. The UPD of metals, which in general involves the deposition of up to a monolayer of metal on a foreign substrate at potentials positive to the reversible thermodynamic potential, facilitates this type of surface modification, which can be performed repeatedly by potential control. Recent studies of these surfaces and their catalytic properties by new in situ surface structure sensitive techniques have greatly improved the understanding of these systems.

  17. Hydrophilic nanoporous polystyrenes and 1,2-polybutadienes

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Jankova Atanasova, Katja; Vigild, Martin Etchells

    2008-01-01

    Nanoporous polymers from ordered block copolymers having hydrophilic cavity surfaces were successfully prepared by two methodologies: ' 1. Nanoporous polystyrenes fromPtBA-b-PS diblock or PDMS-b-PtBA-b-PS triblock copolymer precursors by atom transfer radical polymerization (ATRP), or combination...... of living anionic polymerization~ and ATRP r~spectively. The one, PtBA block, can be modified to the hydrophilic PAA, where the dther, polydimethysiloxane (PDMS) block, can be fully degraded. Deprotection of the tert-butyl groups in PtBA and the selective etching of PDMS· chains were accomplished...... by applying HF or TFA in one step. Thus both the di- and triblock copolymers after such a treatment resulted. in nanoporous polystyrenes with hexagonal cavities of different nanosizes (6-11 nm, Figure 1). 2. Nanoporous I,2-polybutadienes (I,2-PB) by grafting various acrylic monomers onto the pore. surfaces...

  18. Transport and retention of strontium in surface-modified quartz sand with different wettability

    International Nuclear Information System (INIS)

    Yifei Li; Shuaihui Tian; Tianwei Qian

    2011-01-01

    Instead of radioactive 90 Sr, common strontium chloride was used to simulate the migration of radioactive strontium chloride in surface hydroxylated, silanized, and common quartz sand. The sorption and retardation characteristics of strontium (Sr 2+ ) in these surface modified quartz sands were studied by batch tests and column experiments. The equilibrium sorption data for Sr 2+ on different wettability sands were described by the Langmuir and Freundlich isotherm models, and the Langmuir model has been found to provide better correlation for hydrophilic sand. The breakthrough curves (BTCs) of Sr 2+ in these media were analyzed with the equilibrium convection-dispersion equation (CDE) and a non-equilibrium two-region mobile-immobile model (TRM) using a nonlinear least square curve-fitting program CXTFIT. The TRM model showed better fit to the measured BTCs of Sr 2+ , and the parameters of the fraction of mobile water indicated that significant preferential flow effected the non-equilibrium transport of Sr 2+ . Although TRM model could not fit the Sr 2+ BTCs very well, the parameter estimated by TRM model may be more reliable than those obtained from batch experiments because the transport of Sr 2+ in these kind of sand is non-equilibrium processes. (author)

  19. Eco-friendly aqueous core surface-modified nanocapsules.

    Science.gov (United States)

    Carbone, C; Musumeci, T; Lauro, M R; Puglisi, G

    2015-01-01

    In this work, positively charged nanocapsules have been developed for potential ocular delivery exploiting the deposition of PLA onto the droplet surface of a W/O nanoemulsion prepared by the reversed procedure of the PIT method. PLA in combination with different amounts of various oils and surfactants have been studied in order to select the best formulation for polymeric nanocapsule preparation. The traditional visual observation together with the Turbiscan(®) technology were exploited in order to identify the best combination of polymer/oil for nanocapsule preparation. Two different primary surfactants (Span(®) 60 and Span(®) 80) have been tested to select their influence on the field of existence of the nanoemulsion by the construction of the pseudoternary phase diagrams. Cationic hybrid NC have been prepared by the addition of a coating layer of DDAB. The physico-chemical and morphological properties of all the prepared nanocapsules have been evaluated and compared by PCS, DSC and AFM. Therefore, positively charged nanocapsules can be easily prepared by a simple eco-friendly technique that exploits biocompatible materials avoiding a large input of mechanical energy as a potential ocular delivery systems for hydrophilic compounds or gene materials. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. A flow chamber assay for quantitative evaluation of bacterial surface colonization used to investigate the influence of temperature and surface hydrophilicity on the biofilm forming capacity of uropathogenic Escherichia coli

    DEFF Research Database (Denmark)

    Andersen, Thomas Emil; Kingshott, Peter; Palarasah, Yaseelan

    2010-01-01

    to those found on an implanted device. We have used the method to evaluate the biofilm forming capacity of clinically isolated Escherichia coli on silicone rubber and on silicone rubber containing a hydrophilic coating. It was found that the surface chemistry influenced the colonization of the isolates...... very differently. In addition, the temperature was found to have a considerable influence upon the adhesion and biofilm forming capacity of some of the isolates, and that the influence of surface chemistry depended on temperature. Our results suggest that the step from using E. coli laboratory strains...

  1. Competitive Protein Adsorption on Polysaccharide and Hyaluronate Modified Surfaces

    Science.gov (United States)

    Ombelli, Michela; Costello, Lauren; Postle, Corinne; Anantharaman, Vinod; Meng, Qing Cheng; Composto, Russell J.; Eckmann, David M.

    2011-01-01

    We measured adsorption of bovine serum albumin (BSA) and fibrinogen (Fg) onto six distinct bare and dextran- and hyaluronate-modified silicon surfaces created using two dextran grafting densities and three hyaluronic acid (HA) sodium salts derived from human umbilical cord, rooster comb and streptococcus zooepidemicus. Film thickness and surface morphology depended on HA molecular weight and concentration. BSA coverage was enhanced on surfaces upon competitive adsorption of BSA:Fg mixtures. Dextranization differentially reduced protein adsorption onto surfaces based on oxidation state. Hyaluronization was demonstrated to provide the greatest resistance to protein coverage, equivalent to that of the most resistant dextranized surface. Resistance to protein adsorption was independent of the type of hyaluronic acid utilized. With changing bulk protein concentration from 20 to 40 µg ml−1 for each species, Fg coverage on silicon increased by 4×, whereas both BSA and Fg adsorption on dextran and HA were far less dependent of protein bulk concentration. PMID:21623481

  2. Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

    Science.gov (United States)

    Zhao, Yi-Fan; Zhang, Pei-Bin; Sun, Jian; Liu, Cui-Jing; Yi, Zhuan; Zhu, Li-Ping; Xu, You-Yi

    2015-06-15

    Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site. Poly(sulfobetaine methacrylate) (PSBMA) were subsequently grafted onto the PES blend membranes by surface-initiated atom transfer radical polymerization (SI-ATRP). The analysis of surface chemistry confirmed the successful grafting of zwitterionic PSBMA brushes on PES membrane surface. The resulted PES-g-PSBMA membranes were capable of separating proteins from protein solution and oil from oil/water emulsion efficiently. Furthermore, the modified membranes showed high hydrophilicity and strongly antifouling properties due to the incorporation of well-defined PSBMA layer. In addition, the PES-g-PSBMA membranes exhibited excellent blood compatibility and durability during the washing process. The developed antifouling PES membranes are versatile and can find their applications in protein filtration, blood purification and oil/water separation, etc. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. High Stability Pentacene Transistors Using Polymeric Dielectric Surface Modifier.

    Science.gov (United States)

    Wang, Xiaohong; Lin, Guangqing; Li, Peng; Lv, Guoqiang; Qiu, Longzhen; Ding, Yunsheng

    2015-08-01

    1,6-bis(trichlorosilyl)hexane (C6Cl), polystyrene (PS), and cross-linked polystyrene (CPS) were investigated as gate dielectric modified layers for high performance organic transistors. The influence of the surface energy, roughness and morphology on the charge transport of the organic thin-film transistors (OTFTs) was investigated. The surface energy and roughness both affect the grain size of the pentacene films which will control the charge carrier mobility of the devices. Pentacene thin-film transistors fabricated on the CPS modified dielectric layers exhibited charge carrier mobility as high as 1.11 cm2 V-1 s-1. The bias stress stability for the CPS devices shows that the drain current only decays 1% after 1530 s and the mobility never decreases until 13530 s.

  4. Novel Hierarchical Micro/Nano Modified Surfaces for Dental Implants

    Directory of Open Access Journals (Sweden)

    Gabriela STRNAD

    2018-06-01

    Full Text Available Present paper presents the modification at nano scale level of the surfaces of Ti6Al4V alloy that were previously modified at micro scale level by acid etching (AE or by sand blasting with large grit and acid etching (SLA. Continuous, self-ordered nanostructured (nanoporous/nanotubular oxide layers superimposed onto micro rough topographies were developed by using electrochemical anodization in fluoride based solutions, and optimized process parameters. Novel hierarchical micro/nano modified surfaces, with well developed oxide nanotubes of 40-110 nm in diameter, were synthesis by anodization in 1M H3PO4 + 0.4 wt% HF electrolyte, at anodization potential of 24 V, applied with a potential ramp of 0.08 V/s.

  5. A facile strategy for the fabrication of a bioinspired hydrophilic-superhydrophobic patterned surface for highly efficient fog-harvesting

    KAUST Repository

    Wang, Yuchao; Zhang, Lianbin; Wu, Jinbo; Hedhili, Nejib; Wang, Peng

    2015-01-01

    Fog water collection represents a meaningful effort in the places where regular water sources, including surface water and ground water, are scarce. Inspired by the amazing fog water collection capability of Stenocara beetles in the Namib Desert

  6. Evolution and accumulation of organic foulants on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor

    KAUST Repository

    Matar, Gerald; Gonzalez-Gil, G.; Maab, H.; Nunes, Suzana Pereira; Vrouwenvelder, J.S.; Saikaly, Pascal

    2015-01-01

    foulants with time, illustrating that membrane surface chemistry did not affect the selection of specific organic foulants. Multivariate analysis showed that biofilm samples clustered according to the day of sampling. The composition of organic foulants

  7. Strengthening and toughening of poly(L-lactide) composites by surface modified MgO whiskers

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Wei [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Luo, Binghong, E-mail: tluobh@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Qin, Xiaopeng; Li, Cairong [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Liu, Mingxian; Ding, Shan [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China)

    2015-03-30

    Highlights: • The grafted PLLA chain on the surface of g-MgO whisker was ruled out by FTIR spectroscopy and TG/DTG analyses. • The excellent dispersion of g-MgO whiskers and the strong interfacial adhesion of g-MgO whiskers/PLLA composite were proved by FSEM. • Comparing to MgO particles and MgO whiskers, fibrous-like g-MgO whiskers are the most effective reinforcing and toughening fillers for PLLA. - Abstract: To improve both the strength and toughness of poly(L-lactide) (PLLA), fibrous-like MgO whiskers with diameters of 0.15–1 μm and lengths of 15–110 μm were prepared, and subsequently surface modified with L-lactide to obtain grafted MgO whiskers (g-MgO whiskers). The structures and properties of MgO whiskers and g-MgO whiskers were studied. Then, a series of MgO whiskers/PLLA and g-MgO whiskers/PLLA composites were prepared by solution casting method, for comparison, MgO particles/PLLA composite was prepared too. The resulting composites were evaluated in terms of hydrophilicity, crystallinity, dispersion of whiskers, interfacial adhesion and mechanical performance by means of polarized optical microscopy (POM), contact angle measurement, field emission scanning electron microscope (FSEM), transmission electron microscopy (TEM) and tensile testing. The results revealed that the crystallization rate and hydrophilicity of PLLA were improved by the introduction of MgO whiskers and g-MgO whiskers. The g-MgO whiskers can disperse more uniformly in and show stronger interfacial adhesion with the matrix than MgO whiskers as a result of the surface modification. Due to the bridge effect of the whiskers and the excellent interfacial adhesion between g-MgO whiskers and PLLA, g-MgO whiskers/PLLA composites exhibited remarkably higher strength, modulus and toughness compared to the pristine PLLA, MgO particles/PLLA and MgO whiskers/PLLA composites.

  8. Preparation and characterization of dopamine-decorated hydrophilic carbon black

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lijun; Lu Yonglai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Yiqing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China); Zhang Liqun [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Wencai, E-mail: wangw@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China)

    2012-05-01

    Inspired by the bio-adhesive proteins secreted by mussels for attachment to almost all wet substrates, a facile method involving oxidative polymerization of dopamine was proposed to prepare highly hydrophilic carbon black (CB) particles. A self-assembled polydopamine (PDA) ad-layer was formed via the oxidative polymerization of dopamine on the surface of CB simply by dipping the CB into an alkaline dopamine solution and mildly stirring at room temperature. The process is simple, controllable, and environment-friendly. The surface composition and structure of the CB were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The surface morphology of the CB was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the PDA ad-layer was successfully deposited on the CB surfaces. The PDA-functionalized CB (CB-PDA) gave a stable colloidal dispersion in water. Contact angle measurement results indicated that the hydrophilicity of CB was significantly improved after dopamine modification. TGA results confirmed that the modified CB maintained good heat resistance. The method provided a facile route to prepare hydrophilic CB having terminal hydroxyl groups.

  9. Osteogenic potential of laser modified and conditioned titanium zirconium surfaces

    Directory of Open Access Journals (Sweden)

    P David Charles

    2016-01-01

    Full Text Available Statement of Problem: The osseointegration of dental implant is related to their composition and surface treatment. Titanium zirconium (TiZr has been introduced as an alternative to the commercially pure titanium and its alloys as dental implant material, which is attributed to its superior mechanical and biological properties. Surface treatments of TiZr have been introduced to enhance their osseointegration ability; however, reliable, easy to use surface modification technique has not been established. Purpose: The purpose of this study was to evaluate and compare the effect of neodymium-doped yttrium aluminum garnet (Nd-YAG laser surface treatment of TiZr implant alloy on their osteogenic potential. Materials and Methods: Twenty disc-shaped samples of 5 mm diameter and 2 mm height were milled from the TiZr alloy ingot. The polished discs were ultrasonically cleaned in distilled water. Ten samples each were randomly selected as Group A control samples and Group B consisted of Nd-YAG laser surface etched and conditioned test samples. These were evaluated for cellular response. Cellular adhesion and proliferation were quantified, and the results were statistically analyzed using nonparametric analysis. Cellular morphology was observed using electron and epiflurosence microscopy. Results: Nd-YAG laser surface modified and conditioned TiZr samples increased the osteogenic potential. Conclusion: Nd-YAG laser surface modification of TiZr, improves the cellular activity, surface roughness, and wettability, thereby increasing the osteogenic potential.

  10. Formas farmacêuticas de liberação modificada: polímeros hidrifílicos Modified release of drug delivery systems: hydrophilic polymers

    Directory of Open Access Journals (Sweden)

    Carla Martins Lopes

    2005-06-01

    Full Text Available Os sistemas de liberação de fármacos são parte integrante da investigação farmacêutica. A maioria dos sistemas de liberação oral de fármacos é baseada em matrizes poliméricas. Nas duas décadas passadas, as matrizes hidrofílicas tornaram-se muito populares na formulação de formas farmacêuticas de liberação modificada. A escolha do polímero hidrofílico na formulação da matriz pode fornecer uma combinação apropriada dos mecanismos de intumescimento, de dissolução ou de erosão e determinam a cinética de liberação in vitro. As matrizes de intumescimento são sistemas monolíticos preparados pela compressão de mistura de um polímero hidrofílico e de um fármaco. Elas representam sistemas da liberação em que os vários mecanismos podem ser adaptados ao programa de liberação. O sucesso desses sistemas está relacionado com a tecnologia de fabricação e com as características físicas e físico-químicas do polímero, responsáveis pelo mecanismo de liberação.Drug delivery systems (DDS became an integral part of pharmaceutical research. The majority of oral DDS are matrix-based systems. Hydrophilic matrices for the past two decades have been popular in the formulation of controlled release solid dosage forms. Swellable matrices are monolithic systems prepared by compression of a powdered mixture of a hydrophilic polymer and a drug. They represent a delivery system in which various mechanisms can be adapted to the delivery program. Their success is linked to the established tabletting technology of manufacture. The choice of the hydrophilic polymer in the matrix formulation can provide an appropriate combination of swelling, dissolution or erosion mechanisms to evaluate in vitro release kinetics.

  11. Evidence of the no-slip boundary condition of water flow between hydrophilic surfaces using atomic force microscopy.

    Science.gov (United States)

    Maali, Abdelhamid; Wang, Yuliang; Bhushan, Bharat

    2009-10-20

    In this study we present measurements of the hydrodynamic force exerted on a glass sphere glued to an atomic force microscopy (AFM) cantilever approaching a mica surface in water. A large sphere was used to reduce the impact of the cantilever beam on the measurement. An AFM cantilever with large stiffness was used to accurately determine the actual contact position between the sphere and the sample surface. The measured hydrodynamic force with different approach velocities is in good agreement with the Taylor force calculated in the lubrication theory with the no-slip boundary conditions, which verifies that there is no boundary slip on the glass and mica surfaces. Moreover, a detailed procedure of how to subtract the electrostatic double-layer force is presented.

  12. Surface-modified gold nanorods for specific cell targeting

    Science.gov (United States)

    Wang, Chan-Ung; Arai, Yoshie; Kim, Insun; Jang, Wonhee; Lee, Seonghyun; Hafner, Jason H.; Jeoung, Eunhee; Jung, Deokho; Kwon, Youngeun

    2012-05-01

    Gold nanoparticles (GNPs) have unique properties that make them highly attractive materials for developing functional reagents for various biomedical applications including photothermal therapy, targeted drug delivery, and molecular imaging. For in vivo applications, GNPs need to be prepared with very little or negligible cytotoxicitiy. Most GNPs are, however, prepared using growth-directing surfactants such as cetyl trimethylammonium bromide (CTAB), which are known to have considerable cytotoxicity. In this paper, we describe an approach to remove CTAB to a non-toxic concentration. We optimized the conditions for surface modification with methoxypolyethylene glycol thiol (mPEG), which replaced CTAB and formed a protective layer on the surface of gold nanorods (GNRs). The cytotoxicities of pristine and surface-modified GNRs were measured in primary human umbilical vein endothelial cells and human cell lines derived from hepatic carcinoma cells, embryonic kidney cells, and thyroid papillary carcinoma cells. Cytotoxicity assays revealed that treating cells with GNRs did not significantly affect cell viability except for thyroid papillary carcinoma cells. Thyroid cancer cells were more susceptible to residual CTAB, so CTAB had to be further removed by dialysis in order to use GNRs for thyroid cell targeting. PEGylated GNRs are further modified to present monoclonal antibodies that recognize a specific surface marker, Na-I symporter, for thyroid cells. Antibody-conjugated GNRs specifically targeted human thyroid cells in vitro.

  13. Coke degradation by surface breakage in a modified tumble drum

    Energy Technology Data Exchange (ETDEWEB)

    Litster, J D

    1987-01-01

    The surface breakage rate constant for three Australian battery cokes was measured in a specially modified tumble drum using a previously developed technique. The effect of experimental test parameters - coke size, sample mass, drum speed, lifter height and lifter number - on the surface breakage rate constant was examined. The motion of coke particles within a tumble drum was filmed in a simulation experiment with a 0.31 m diameter drum. Particles were raised on the lifters, fell and collided with the bottom of the drum. These collisions were the main source of fines (minus 1 mm) production rather than true abrasion as depicted by a rubbing, rolling action. Hence the term 'surface breakage' is more appropriate than 'abrasion' to describe the breakage process. By measuring the volume of coke carried by each lifter and the height of fall of the coke, the effect of drum speed, sample mass, lifter height and number on the rate of surface breakage was successfully explained. The surface breakage rate constant was found to be proportional to particle size to the power 0.33 for the three cokes studied. A normalized surface breakage rate constant was derived which allowed comparison of cokes with different size distributions. This parameter characterises the coke surface breakage resistance.

  14. Improved surface hydrophilicity and antifouling property of polysulfone ultrafiltration membrane with poly(ethylene glycol) methyl ether methacrylate grafted graphene oxide nanofillers

    Science.gov (United States)

    Wang, Haidong; Lu, Xiaofei; Lu, Xinglin; Wang, Zhenghui; Ma, Jun; Wang, Panpan

    2017-12-01

    In this study, the GO-g-P(PEGMA) nanoplates were first synthesized by grafting hydrophilic poly (poly (ethylene glycol) methyl ether methacrylate) via surface-initiated atom transfer radical polymerization (SI-ATRP) method. A novel polysulfone (PSF) nanocomposite membrane using GO-g-P(PEGMA) nanoplates as nanofillers was fabricated. FTIR, TGA, 1H NMR, GPC and TEM were applied to verify the successful synthesis of the prepared nanoplates, while SEM, AFM, XPS, contact angle goniometry and filtration experiments were used to characterize the fabricated nanocomposite membranes. It was found that the new prepared nanofillers were well dispersed in organic PSF matrix, and the PSF/GO-g-P(PEGMA) nanocomposite membrane showed significant improvements in water flux and flux recovery rate. Based on the results of resistance-in-series model, the nanocomposite membrane exhibited superior resistance to the irreversible fouling. The excellent filtration and antifouling performance are attributed to the segregation of GO-g-P(PEMGA) nanofillers toward the membrane surface and the pore walls. Notably, the blended nanofillers appeared a stable retention in/on nanocomposite membrane after 30 days of washing time. The demonstrated method of synthesis GO-g-P(PEGMA) in this study can also be extended to preparation of other nanocomposite membrane in future.

  15. The role of mineral surface chemistry in modified dextrin adsorption.

    Science.gov (United States)

    Beaussart, Audrey; Mierczynska-Vasilev, Agnieszka M; Harmer, Sarah L; Beattie, David A

    2011-05-15

    The adsorption of two modified dextrins (phenyl succinate dextrin--PS Dextrin; styrene oxide dextrin--SO Dextrin) on four different mineral surfaces has been studied using X-ray photoelectron spectroscopy (XPS), in situ atomic force microscopy (AFM) imaging, and captive bubble contact angle measurements. The four surfaces include highly orientated pyrolytic graphite (HOPG), freshly cleaved synthetic sphalerite (ZnS), and two surfaces produced through surface reactions of sphalerite: one oxidized in alkaline solution (pH 9, 1 h immersion); and one subjected to metal ion exchange between copper and zinc (i.e. copper activation: exposed to 1×10(-3) M CuSO(4) solution for 1 h). XPS measurements indicate that the different sphalerite surfaces contain varying amounts of sulfur, zinc, oxygen, and copper, producing substrates for polymer adsorption with a range of possible binding sites. AFM imaging has shown that the two polymers adsorb to a similar extent on HOPG, and that the two polymers display very different propensities for adsorption on the three sphalerite surface types, with freshly cleaved sphalerite encouraging the least adsorption, and copper activated and oxidized sphalerite encouraging significantly more adsorption. Contact angle measurements of the four surfaces indicate that synthetic sphalerite has a low contact angle upon fracture, and that oxidation on the timescale of one hour substantially alters the hydrophobicity. HOPG and copper-activated sphalerite were the most hydrophobic, as expected due to the carbon and di/poly-sulfide rich surfaces of the two samples, respectively. SO Dextrin is seen to have a significant impact on the wettability of HOPG and the surface reacted sphalerite samples, highlighting the difficulty in selectively separating sphalerite from carbonaceous unwanted minerals in flotation. PS Dextrin has the least effect on the hydrophobicity of the reacted sphalerite surfaces, whilst still significantly increasing the wettability of

  16. Synthesis and Evaluation of Zeolite Surface-Modified Perlite

    Directory of Open Access Journals (Sweden)

    Kasai Makoto

    2017-01-01

    Full Text Available Perlite is volcanic glass mainly composed of amorphous aluminum silicate, mainly composed SiO2 and Al2O3 with less impurities such as heavy metals. Amorphous (glassy perlite is used in lightweight aggregate and insulation. In addition, it has also been used as a filter aid by grinding the expanded perlite. However, it has not been used as environmental cleanup materials, because the ion exchange capacity of the perlite is very low. In this study, we tried to synthesize the hybrid filter aid with chemical adsorption capacity by synthesizing the zeolite on the surface of the perlite. As a result, by using the hydrothermal synthesis method, zeolite surface modified perlite was synthesized in which the LTA type zeolites were generated on the surface of the perlite.

  17. Friction and Wear Management Using Solvent Partitioning of Hydrophilic-Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

    Science.gov (United States)

    Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor)

    2015-01-01

    Lubrication additives of the current invention require formation of emulsions in base lubricants, created with an aqueous salt solution plus a single-phase compound such that partitioning within the resulting emulsion provides thermodynamically targeted compounds for boundary layer organization thus establishing anti-friction and/or anti-wear. The single-phase compound is termed "boundary layer organizer", abbreviated BLO. These emulsion-contained compounds energetically favor association with tribologic surfaces in accord with the Second Law of Thermodynamics, and will organize boundary layers on those surfaces in ways specific to the chemistry of the salt and BLO additives. In this way friction modifications may be provided by BLOs targeted to boundary layers via emulsions within lubricating fluids, wherein those lubricating fluids may be water-based or oil-based.

  18. Porous surface modified bioactive bone cement for enhanced bone bonding.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth.The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant-bone interface was also investigated by push-out tests.The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony defect.Our findings suggested a new bioactive

  19. Synthesis and characterization of nanocomposites based on polyurethane in aqueous dispersions with non-modified hydrophilic clays; Sintese e caracterizacao de nanocompositos a base de poliuretanos em dispersoes aquosas com argilas hidrofilicas nao-modificadas

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, G.S.; Delpechi, M.C.; Santo, W.L.E., E-mail: mcd@uerj.b [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2010-07-01

    Several studies involving the formation of polyurethane nanocomposites employing clays of montmorillonite modified. This involves the presence of quaternary ammonium salts, the cation exchange needed to increase the interlayer space of clays that incorporate more than one step to the process, generates a higher cost. In this paper the synthesis of nanocomposite polyurethanes dispersed in water allowed not only the production of materials less harmful to the environment, but also the incorporation of hydrophilic clays, calcium and sodium in nature, without any modifications. Dispersions produced from 0.5, 1.0 and 2.5% clay (on the mass of prepolymer) were characterized in terms of total solids content, the films obtained by casting were evaluated for adhesiveness, diffraction X-rays, scanning electron microscopy. Most systems showed intercalated and partially exfoliated structures. (author)

  20. Patterning Method for Silver Nanoparticle Electrodes in Fully Solution-Processed Organic Thin-Film Transistors Using Selectively Treated Hydrophilic and Hydrophobic Surfaces

    Science.gov (United States)

    Fukuda, Kenjiro; Takeda, Yasunori; Kobayashi, Yu; Shimizu, Masahiro; Sekine, Tomohito; Kumaki, Daisuke; Kurihara, Masato; Sakamoto, Masatomi; Tokito, Shizuo

    2013-05-01

    Fully solution-processed organic thin-film transistor (OTFT) devices have been fabricated with simple patterning process at a relatively low process temperature of 100 °C. In the patterning process, a hydrophobic amorphous fluoropolymer material, which was used as the gate dielectric layer and the underlying base layer, was treated with an oxygen plasma to selectively change its surface wetting properties from hydrophobic to hydrophilic. Silver source and drain electrodes were successfully formed in the treated areas with highly uniform line widths and without residues between the electrodes. Nonuniformities in the thickness of the silver electrodes originating from the “coffee-ring” effect were suppressed by optimizing the blend of solvents used with the silver nanoparticles, such that the printed electrodes are appropriate for bottom-gate OTFT devices. A fully solution-processed OTFT device using a polymer semiconductor material (PB16TTT) exhibited good electrical performance with no hysteresis in its transfer characteristics and with good linearity in its output characteristics. A relatively high carrier mobility of 0.14 cm2 V-1 s-1 and an on/off ratio of 1×105 were obtained with the fabricated TFT device.

  1. Bactericidal effects of plasma-modified surface chemistry of silicon nanograss

    International Nuclear Information System (INIS)

    Ostrikov, Kola; Macgregor-Ramiasa, Melanie; Cavallaro, Alex; Ostrikov, Kostya; Vasilev, Krasimir

    2016-01-01

    The surface chemistry and topography of biomaterials regulate the adhesion and growth of microorganisms in ways that are still poorly understood. Silicon nanograss structures prepared via inductively coupled plasma etching were coated with plasma deposited nanometer-thin polymeric films to produce substrates with controlled topography and defined surface chemistry. The influence of surface properties on Staphylococcus aureus proliferation is demonstrated and explained in terms of nanograss substrate wetting behaviour. With the combination of the nanograss topography; hydrophilic plasma polymer coatings enhanced antimicrobial activity while hydrophobic coatings reduced it. This study advances the understanding of the effects of surface wettability on the bactericidal properties of reactive nano-engineered surfaces. (paper)

  2. Comblike poly(ethylene oxide)/hydrophobic C6 branched chitosan surfactant polymers as anti-infection surface modifying agents.

    Science.gov (United States)

    Mai-ngam, Katanchalee

    2006-05-01

    A series of structurally well-defined poly(ethylene oxide)/hydrophobic C6 branched chitosan surfactant polymers that undergo surface induced self assembly on hydrophobic biomaterial surfaces were synthesized and characterized. The surfactant polymers consist of low molecular weight (Mw) chitosan backbone with hydrophilic poly(ethylene oxide) (PEO) and hydrophobic hexyl pendant groups. Chitosan was depolymerized by nitrous acid deaminative cleavage. Hexanal and aldehyde-terminated PEO chains were simultaneously attached to low Mw chitosan hydrochloride via reductive amination. The surfactant polymers were prepared with various ratios of the two side chains. The molecular composition of the surfactant polymers was determined by FT-IR and 1H NMR. Surface active properties at the air-water interface were determined by Langmuir film balance measurements. The surfactant polymers with PEO/hexyl ratios of 1:3.0 and 1:14.4 were used as surface modifying agents to investigate their anti-infection properties. E. coli adhesion on Silastic surface was decreased significantly by the surfactant polymer with PEO/hexyl 1:3.0. Surface growth of adherent E. coli was effectively suppressed by both tested surfactant polymers.

  3. Development of a Modified Vacuum Cleaner for Lunar Surface Systems

    Science.gov (United States)

    Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

    2010-01-01

    The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf' vacuum cleaner will be used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques in order to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating particulate removal, relative to the retained simulant on the tested surface. In addition, optical microscopy was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has

  4. Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

    International Nuclear Information System (INIS)

    Zhang, Y.; Wu, Q.; Zhang, H.; Zhao, J.

    2013-01-01

    Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications

  5. Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: zhyw@dhu.edu.cn; Wu, Q.; Zhang, H.; Zhao, J. [Donghua University, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Chemical Fibers Research Institute (China)

    2013-07-15

    Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications.

  6. Eutrophication management in surface waters using lanthanum modified bentonite

    DEFF Research Database (Denmark)

    Copetti, Diego; Finsterle, Karin; Marziali, Laura

    2016-01-01

    This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales. The availa......This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales....... The available data underline a high efficiency for phosphorus binding. This efficiency can be limited by the presence of humic substances and competing oxyanions. Lanthanum concentrations detected during a LMB application are generally below acute toxicological threshold of different organisms, except in low...... alkalinity waters. To date there are no indications for long-term negative effects on LMB treated ecosystems, but issues related to La accumulation, increase of suspended solids and drastic resources depletion still need to be explored, in particular for sediment dwelling organisms. Application of LMB...

  7. Hydrophilic PCU scaffolds prepared by grafting PEGMA and immobilizing gelatin to enhance cell adhesion and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Changcan; Yuan, Wenjie; Khan, Musammir; Li, Qian [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@tju.edu.cn [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, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin) Tianjin 300072 (China); Yao, Fanglian [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, Tianjin 300072 (China); Zhang, Wencheng, E-mail: wenchengzhang@yahoo.com [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China)

    2015-05-01

    Gelatin contains many functional motifs which can modulate cell specific adhesion, so we modified polycarbonate urethane (PCU) scaffold surface by immobilization of gelatin. PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatins onto the surface of aminated PCU scaffolds. To increase the immobilization amount of gelatin, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto PCU scaffolds by surface initiated atom transfer radical polymerization. Then, following amination and immobilization, PCU-g-PEGMA-g-gelatin scaffolds were obtained. Both modified scaffolds were characterized by chemical and biological methods. After immobilization of gelatin, the microfiber surface became rough, but the original morphology of scaffolds was maintained successfully. PCU-g-PEGMA-g-gelatin scaffolds were more hydrophilic than PCU-g-gelatin scaffolds. Because hydrophilic PEGMA and gelatin were grafted and immobilized onto the surface, the PCU-g-PEGMA-g-gelatin scaffolds showed low platelet adhesion, perfect anti-hemolytic activity and excellent cell growth and proliferation capacity. It could be envisioned that PCU-g-PEGMA-g-gelatin scaffolds might have potential applications in tissue engineering artificial scaffolds. - Graphical abstract: PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatin onto the surface of aminated PCU scaffolds (method a). To increase the immobilization amount of gelatin, PEGMAs were grafted onto the scaffold surface by SI-ATRP. PCU-g-PEGMA-g-gelatin scaffolds were prepared by method b. The gelatin modified scaffolds exhibited high hydrophilicity, low platelet adhesion, perfect anti-hemolytic activity, and excellent cell adhesion and proliferation capacity. They might have potential applications as tissue engineering scaffolds for artificial blood vessels. - Highlights: • Hydrophilic scaffolds were prepared by grafting PEGMA and immobilization of gelatins. • Grafting PEGMA enhanced the immobilization amount of gelatin

  8. Mesoporous bioactive glass surface modified poly(lactic-co-glycolic acid electrospun fibrous scaffold for bone regeneration

    Directory of Open Access Journals (Sweden)

    Chen SJ

    2015-06-01

    Full Text Available Shijie Chen,1,* Zhiyuan Jian,2,* Linsheng Huang,2,* Wei Xu,3,* Shaohua Liu,4 Dajiang Song,3 Zongmiao Wan,3 Amanda Vaughn,5 Ruisen Zhan,1 Chaoyue Zhang,1 Song Wu,1 Minghua Hu,6 Jinsong Li1 1Department of Orthopaedics, The Third Xiangya Hospital of Central South University, Changsha, Hunan, People’s Republic of China; 2The First General Surgery Department of Shiyan Taihe Hospital Affiliated to Hubei University of Medicine, Shiyan, People’s Republic of China; 3Department of Orthopedic Oncology, Changzheng Hospital, The Second Military Medical University, Shanghai, People’s Republic of China; 4Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan, People’s Republic of China; 5Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA; 6Department of Anthropotomy, Changsha Medical College, Changsha, Hunan, People’s Republic of China *These authors contributed equally to this work Abstract: A mesoporous bioactive glass (MBG surface modified with poly(lactic-co-glycolic acid (PLGA electrospun fibrous scaffold for bone regeneration was prepared by dip-coating a PLGA electrospun fibrous scaffold into MBG precursor solution. Different surface structures and properties were acquired by different coating times. Surface morphology, chemical composition, microstructure, pore size distribution, and hydrophilicity of the PLGA-MBG scaffold were characterized. Results of scanning electron microscopy indicated that MBG surface coating made the scaffold rougher with the increase of MBG content. Scaffolds after MBG modification possessed mesoporous architecture on the surface. The measurements of the water contact angles suggested that the incorporation of MBG into the PLGA scaffold improved the surface hydrophilicity. An energy dispersive spectrometer evidenced that calcium-deficient carbonated hydroxyapatite formed on the PLGA-MBG scaffolds

  9. Experimental studies of surface modified oscillating heat pipes

    Science.gov (United States)

    Leu, Tzong-Shyng; Wu, Cheng-Han

    2017-11-01

    Oscillating heat pipe (OHP) is a two-phase heat transfer device which has the characteristics of simple construction, high heat flux capability and no need of wicking structures for liquid transport. There are many studies in finding the ways how to improve the system performance OHP. In this paper, studies of the effects of contact angle ( θ c ) on the inner wall of OHP system have been conducted first. Glass OHP systems with unmodified ( θ c = 26.74°), superhydrophobic ( θ c = 156.2°), superhydrophilic ( θ c evaporator region and superhydrophobic within condensation region) surfaces, are studied. The research results indicated that thermal resistance of these four OHP systems can be significantly affected by different surface modification approaches. Although superhydrophobic OHP system can still work, the thermal resistance ( R th ) is the highest one of the four OHP systems, R th = 0.36 °C/W at 200 W. Unmodified pure glass and superhydrophilic OHP systems have similar performance. Thermal resistances are 0.28 and 0.27 °C/W at 200 W respectively. The hybrid OHP achieves the lowest thermal resistance, R th = 0.23 °C/W at 200 W in this study. The exact mechanism and effects of contact angle on OHP systems are investigated with the help of flow visualization. By comparing the flow visualization results of OHP systems before and after surface modification, one tries to find the mechanism how the surface modified inner wall surface affects the OHP system performance. In additional to the reason that the superhydrophobic dropwise condensation surface inside the hybrid OHP system, hybrid OHP system shows more stable and energetic circulation flow. It is found that instead of stratified flow, vapor slug flows are identified within the evaporator section of the hybrid OHP system that can effectively generate higher pressure force for two phase interfacial flow. This effect is attributed to be the main mechanism for better performance of the hybrid OHP system.

  10. Hydrophilic Carotenoids: Recent Progress

    Directory of Open Access Journals (Sweden)

    Attila Agócs

    2012-04-01

    Full Text Available Carotenoids are substantially hydrophobic antioxidants. Hydrophobicity is this context is rather a disadvantage, because their utilization in medicine as antioxidants or in food chemistry as colorants would require some water dispersibility for their effective uptake or use in many other ways. In the past 15 years several attempts were made to synthetize partially hydrophilic carotenoids. This review compiles the recently synthetized hydrophilic carotenoid derivatives.

  11. Enhanced Hydrophilicity and Biocompatibility of Dental Zirconia Ceramics by Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Ching-Chou Wu

    2015-02-01

    Full Text Available Surface properties play a critical role in influencing cell responses to a biomaterial. The objectives of this study were (1 to characterize changes in surface properties of zirconia (ZrO2 ceramic after oxygen plasma treatment; and (2 to determine the effect of such changes on biological responses of human osteoblast-like cells (MG63. The results indicated that the surface morphology was not changed by oxygen plasma treatment. In contrast, oxygen plasma treatment to ZrO2 not only resulted in an increase in hydrophilicity, but also it retained surface hydrophilicity after 5-min treatment time. More importantly, surface properties of ZrO2 modified by oxygen plasma treatment were beneficial for cell growth, whereas the surface roughness of the materials did not have a significant efficacy. It is concluded that oxygen plasma treatment was certified to be effective in modifying the surface state of ZrO2 and has the potential in the creation and maintenance of hydrophilic surfaces and the enhancement of cell proliferation and differentiation.

  12. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O2/H2O low-temperature plasma treatment

    Science.gov (United States)

    You, Xuewei; Gou, Li; Tong, Xingye

    2016-01-01

    The natural leather was modified through O2/H2O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O2/H2O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  13. A Prospective Case-Control Clinical Study of Titanium-Zirconium Alloy Implants with a Hydrophilic Surface in Patients with Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Cabrera-Domínguez, José; Castellanos-Cosano, Lizett; Torres-Lagares, Daniel; Machuca-Portillo, Guillermo

    To evaluate prospectively the behavior of narrow-diameter (3.3-mm) titanium-zirconium alloy implants with a hydrophilic surface (Straumann Roxolid SLActive) in patients with type 2 diabetes mellitus in single-unit restorations, compared with a healthy control group (assessed using the glycosylated hemoglobin HbA1c test). The patients evaluated in this study required single-unit implant treatment; 15 patients had type 2 diabetes mellitus, and 14 patients were healthy (control group [CG]). Marginal bone level (MBL) change around the implants was evaluated using conventional, sequential periapical digital radiographs. Patient HbA1c was assessed in each check-up. Normality test (Kolmogorov-Smirnov), univariate and multivariate logistic regression, analysis of variance (ANOVA), and Mann-Whitney U test were used for statistical analysis. No differences in MBL change and implant survival and success rates were found between the diabetes mellitus group (DMG) versus the control group, either during the initial recording (DMG, 0.99 ± 0.56 vs CG, 0.68 ± 0.54; P > .05) or 6 months after restoration (DMG, 1.28 ± 0.38 vs CG, 1.11 ± 0.59; P > .05). No significant correlation between HbA1c levels and MBL change was detected in these patients (P > .05). Patients with glycemic control exhibit similar outcomes to healthy individuals with regard to the investigated parameters. In light of these findings, the titanium-zirconium alloy small-diameter implants can be used in the anterior region of the mouth in type 2 diabetic patients.

  14. Effects of surface functionalization of hydrophilic NaYF4 nanocrystals doped with Eu3+ on glutamate and GABA transport in brain synaptosomes

    Science.gov (United States)

    Sojka, Bartlomiej; Kociołek, Daria; Banski, Mateusz; Borisova, Tatiana; Pozdnyakova, Natalia; Pastukhov, Artem; Borysov, Arsenii; Dudarenko, Marina; Podhorodecki, Artur

    2017-08-01

    Specific rare earth doped nanocrystals (NCs), a recent class of nanoparticles with fluorescent features, have great bioanalytical potential. Neuroactive properties of NaYF4 nanocrystals doped with Eu3+ were assessed based on the analysis of their effects on glutamate- and γ-aminobutyric acid (GABA) transport process in nerve terminals isolated from rat brain (synaptosomes). Two types of hydrophilic NCs were examined in this work: (i) coated by polyethylene glycol (PEG) and (ii) with OH groups at the surface. It was found that NaYF4:Eu3+-PEG and NaYF4:Eu3+-OH within the concentration range of 0.5-3.5 and 0.5-1.5 mg/ml, respectively, did not influence Na+-dependent transporter-dependent l-[14C]glutamate and [3H]GABA uptake and the ambient level of the neurotransmitters in the synaptosomes. An increase in NaYF4:Eu3+-PEG and NaYF4:Eu3+-OH concentrations up to 7.5 and 3.5 mg/ml, respectively, led to the (1) attenuation of the initial velocity of uptake of l-[14C]glutamate and [3H]GABA and (2) elevation of ambient neurotransmitters in the suspension of nerve terminals. In the mentioned concentrations, nanocrystals did not influence acidification of synaptic vesicles that was shown with pH-sensitive fluorescent dye acridine orange, however, decreased the potential of the plasma membrane of synaptosomes. In comparison with other nanoparticles studied with similar methodological approach, NCs start to exhibit their effects on neurotransmitter transport at concentrations several times higher than those shown for carbon dots, detonation nanodiamonds and an iron storage protein ferritin, whose activity can be registered at 0.08, 0.5 and 0.08 mg/ml, respectively. Therefore, NCs can be considered lesser neurotoxic as compared to above nanoparticles.

  15. Physicochemical state of the nanotopographic surface of commercially pure titanium following anodization-hydrothermal treatment reveals significantly improved hydrophilicity and surface energy profiles.

    Science.gov (United States)

    Takebe, Jun; Ito, Shigeki; Miura, Shingo; Miyata, Kyohei; Ishibashi, Kanji

    2012-01-01

    A method of coating commercially pure titanium (cpTi) implants with a highly crystalline, thin hydroxyapatite (HA) layer using discharge anodic oxidation followed by hydrothermal treatment (Spark discharged Anodic oxidation treatment ; SA-treated cpTi) has been reported for use in clinical dentistry. We hypothesized that a thin HA layer with high crystallinity and nanostructured anodic titanium oxide film on such SA-treated cpTi implant surfaces might be a crucial function of their surface-specific potential energy. To test this, we analyzed anodic oxide (AO) cpTi and SA-treated cpTi disks by SEM and AFM. Contact angles and surface free energy of each disk surface was measured using FAMAS software. High-magnification SEM and AFM revealed the nanotopographic structure of the anodic titanium oxide film on SA-treated cpTi; however, this was not observed on the AO cpTi surface. The contact angle and surface free energy measurements were also significantly different between AO cpTi and SA-treated cpTi surfaces (Tukey's, P<0.05). These data indicated that the change of physicochemical properties of an anodic titanium oxide film with HA crystals on an SA-treated cpTi surface may play a key role in the phenomenon of osteoconduction during the process of osseointegration. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. The Ice Nucleation Activity of Surface Modified Soot

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    The ice nucleation efficiency of many important atmospheric particles remains poorly understood. Since soot is ubiquitous in the Earth's troposphere, they might have the potential to significantly impact the Earth's climate (Finlayson-Pitts and Pitts, 2000; Seinfeld and Pandis, 1998). Here we present the ice nucleation activity (INA) in immersion freezing mode of different types of soot. Therefor a CAST (combustion aerosol standard) generator was used to produce different kinds of soot samples. The CAST generator combusts a propane-air-mixture and deposits thereby produced soot on a polyvinyl fluoride filter. By varying the propane to air ratio, the amount of organic portion of the soot can be varied from black carbon (BC) with no organic content to brown carbon (BrC) with high organic content. To investigate the impact of functional sites of ice nuclei (IN), the soot samples were exposed to NO2 gas for a certain amount of time (30 to 360 minutes) to chemically modify the surface. Immersion freezing experiments were carried out in a unique reaction gadget. In this device a water-in-oil suspension (with the soot suspended in the aqueous phase) was cooled till the freezing point and was observed through a microscope (Pummer et al., 2012; Zolles et al., 2015) It was found that neither modified nor unmodified BC shows INA. On the contrary, unmodified BrC shows an INA at -32˚ C, which can be increased up to -20˚ C. The INA of BrC depends on the duration of NO2- exposure. To clarify the characteristics of the surface modifications, surface sensitive analysis like infrared spectroscopy and X-ray photoelectron spectroscopy were carried out. Finlayson-Pitts, B. J. and Pitts, J. N. J.: Chemistry of the Upper and Lower Atmosphere, Elsevier, New York, 2000. Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S., and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen, Atmos Chem Phys, 12, 2541-2550, 2012. Seinfeld, J

  17. DNA immobilization on polymer-modified Si surface by controlling pH

    International Nuclear Information System (INIS)

    Demirel, Goekcen Birlik; Caykara, Tuncer

    2009-01-01

    A novel approach based on polymer-modified Si surface as DNA sensor platforms is presented. The polymer-modified Si surface was prepared by using 3-(methacryloxypropyl)trimethoxysilane [γ-MPS] and poly(acrylamide) [PAAm]. Firstly, a layer of γ-MPS was formed on the hydroxylated silicon surface as a monolayer and then modified with different molecular weight of PAAm to form polymer-modified surface. The polymer-modified Si surface was used for dsDNA immobilization. All steps about formation of layer structure were characterized by ellipsometry, atomic force microscopy (AFM), attenuated total reflectance Fourier transformed infrared (ATR-FTIR), and contact angle (CA) measurements. We found that in this case the amount of dsDNA immobilized onto the surface was dictated by the electrostatic interaction between the substrate surface and the DNA. Our results thus demonstrated that DNA molecules could be immobilized differently onto the polymer-modified support surface via electrostatic interactions.

  18. STUDY OF SURFACE MODIFIED POLYMERS IN THE MODIFICATION OF NANOMATERIALS

    Directory of Open Access Journals (Sweden)

    G. V. Popov

    2014-01-01

    Full Text Available The comparative study of change of surface tension of solutions of some commercial rubbers before and after thermal ageing technique du-Nui, analyzed the features of change of surface tension of solutions of various rubbers in the presence of a mixture of fullerenes. Calculations of the Gibbs energy and the analysis of the obtained data to predict the behavior of polymer systems when changes are made to mix of fullerenes in a wide concentration range. When comparing the results of changes in Gibbs energy and the surface tension in fluids rubbers shown that mentioned above in solutions of elastomers aged, than the control. This fact confirms the initial chapeau of physic-chemical interactions of molecules fullerenes by segments of the Kuna and end groups of the polymer chains, as it is known that when thermal-oxidative degradation of rubbers, respectively the number of segments of the Kuna and branched loose ends of macromolecules that are free to react with fullerenes in solution, free from spatial constraints. A comparative analysis of the interaction of rubbers with different chemical composition with double branches has shown that it is easier to just react and has minimum energy polibutadien interaction that has to do with lack of branching and no radicals in its structure and in the backbone chain. The maximum energy of interaction with Fullerenes have SBS rubber because it has large styrene blocks in the main polymer chain that causes the spatial constraints to direct contact with fullerene molecules, you can assume that the interaction is only low-molecular fraction of Fullerenes mixture, possessing the necessary dimensions. As a result of the study shows that the application of the method of separation ring (Du-Nui allows you to predict the properties of rubber with modified nanomaterial’s with minimal labor costs.

  19. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma

    International Nuclear Information System (INIS)

    Palacios, J.C.; Chavez, J.A.; Olayo, M.G.; Cruz, G.J.

    2007-01-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  20. Surface characterization and stability of an epoxy resin surface modified with polyamines grafted on polydopamine

    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); Vercammen, Yannick; Van Vaeck, Luc [Biomolecular and Analytical Mass Spectrometry, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Vanderleyden, Els; 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 reports on polydopamine and polyamine surface modifications of an etched epoxy cresol novolac (ECN) resin using the ‘grafting to’ method. Three different polyamines are used for the grafting reactions: branched polyethyleneimine (B-PEI), linear polyethyleneimine (L-PEI) and diethylenetriamine (DETA). These modifications are compared to control materials prepared via direct deposition of polyamines. The stability of the modifications toward a concentrated hydrochloric acid (HCl) environment is evaluated. The modified surfaces are characterized with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectroscopy (TOF-S-SIMS).

  1. Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Fang [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Guangxian, E-mail: zgx656472@sina.com.cn [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Fengxiu [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang, Yuansong [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China)

    2015-09-15

    Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H{sub 2}SO{sub 4} under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric.

  2. Hydrophilic nanoporous materials

    DEFF Research Database (Denmark)

    2010-01-01

    The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.05, the ......The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.......05, the method comprising the steps of: (a) preparing a precursor material comprising at least one polymeric component and having a first phase and a second phase; (b) removal of at least a part of the first phase of the precursor material prepared in step (a) so as to leave behind a nanoporous material...... of the polymer matrix; (c) irradiating at least a part of said nanoporous material with light of a wave length of in the range of 250-400 nm (or 200-700 nm) in the presence of oxygen and/or ozone. Corresponding hydrophilic nanoporous materials are also disclosed. L...

  3. Investigation of surface properties of physico-chemically modified natural fibres using inverse gas chromatography

    CSIR Research Space (South Africa)

    Cordeiro, N

    2011-01-01

    Full Text Available Inverse gas chromatography (IGC) is a suitable method to determine surface energy of natural fibres when compared to wetting techniques. In the present study, the surface properties of raw and modified lignocellulosic fibres have been investigated...

  4. Surface modified carbon nanoparticle papers and applications on polymer composites

    Science.gov (United States)

    Ouyang, Xilian

    Free-standing paper like materials are usually employed as protective layers, chemical filters, components of electrical batteries or supercapacitors, adhesive layers, and electronic or optoelectric components. Free-standing papers made from carbon nanoparticles have drawn increased interest because they have a variety of superior chemical and physical characteristics, such as light weight, high intrinsic mechanical properties, and extraordinary high electrical conductivity. Nanopapers fabricated from 1- D shape carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are promising reinforcing materials for polymer composites, because the highly porous CNF and CNT nanopapers (porosity ˜80% and ˜70% respectively) can be impregnated with matrix polymers. In the first part of this work, polyaniline (PANI) was used to functionalize the surface of CNFs, and the resultant carbon nanopapers presented impressive mechanical strength and electrical conductivity that it could be used in the in-mold coating (IMC)/ injection molding process to achieve high electromagnetic interference (EMI) shielding effectiveness. Aniline modified (AF) CNT nanopapers were used as a 3D network in gas separation membranes. The resultant composite membranes demonstrated better and stable CO2 permeance and CO 2/H2 selectivity in a high temperature (107°C) and high pressure (15-30 atm) gas separation process, not achievable by conventional polymer membranes. In the second part, we demonstrated that 2-D graphene (GP) or graphene oxide (GO) nanosheets could be tightly packed into a film which was impermeable to most gases and liquids. GP or GO nanopapers could be coated on polymer composites. In order to achieve well-dispersed single-layer graphene in aqueous medium, we developed a facile approach to synthesize functional GP bearing benzenesulfonic acid groups which allow the preparation of nanopapers by water based assembly. With the optimized processing conditions, our best GP nanopapers could reach

  5. Wettability Control of Gold Surfaces Modified with Benzenethiol Derivatives: Water Contact Angle and Thermal Stability.

    Science.gov (United States)

    Tatara, Shingo; Kuzumoto, Yasutaka; Kitamura, Masatoshi

    2016-04-01

    The water wettability of Au surfaces has been controlled using various benzenethiol derivatives including 4-methylbenzenethiol, pentafluorobenzenethiol, 4-flubrobenzenethiol, 4-methoxy-benzenethiol, 4-nitrobenzenethiol, and 4-hydroxybenzenethiol. The water contact angle of the Au surface modified with the benzenethiol derivative was found to vary in the wide range of 30.9° to 88.3°. The contact angle of the modified Au films annealed was also measured in order to investigate their thermal stability. The change in the contact angle indicated that the modified surface is stable at temperatures below about 400 K. Meanwhile, the activation energy of desorption from the modified surface was estimated from the change in the contact angle. The modified Au surface was also examined using X-ray photoelectron spectroscopy.

  6. Modified silica sol coatings for surface enhancement of leather.

    Science.gov (United States)

    Mahltig, Boris; Vossebein, Lutz; Ehrmann, Andrea; Cheval, Nicolas; Fahmi, Amir

    2012-06-01

    The presented study reports on differently modified silica sols for coating applications on leather. Silica sols are prepared by acidic hydrolysis of tetraethoxysilane and modified by silane compounds with fluorinated and non-fluorinated alkylgroups. In contrast to many earlier investigations regarding sol-gel applications on leather, no acrylic resin is used together with the silica sols when applying on leather. The modified silica particles are supposed to aggregate after application, forming thus a modified silica coating on the leather substrate. Scanning electron microscopy investigation shows that the applied silica coatings do not fill up or close the pores of the leather substrate. However, even if the pores of the leather are not sealed by this sol-gel coating, an improvement of the water repellent and oil repellent properties of the leather substrates are observed. These improved properties of leather by application of modified silica sols can provide the opportunity to develop sol-gel products for leather materials present in daily life.

  7. Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

    Science.gov (United States)

    Chen, Jianbo

    This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell

  8. Research of the surface properties of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene modified with radio-frequency magnetron sputtering for medical application

    International Nuclear Information System (INIS)

    Tverdokhlebov, S.I.; Bolbasov, E.N.; Shesterikov, E.V.; Malchikhina, A.I.; Novikov, V.A.; Anissimov, Y.G.

    2012-01-01

    Highlights: ► A method for surface modification of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene using radio-frequency magnetron sputtering of hydroxyapatite target is proposed. ► It is demonstrated that the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene surface becomes hydrophilic as the result of the modification. ► It is shown, using atomic force microscopy that the surface potential biases into positive value field and the surface roughness parameters increase as the result of the modification. ► In vitro testing has not found bio-toxicity of investigated surfaces - Abstract: The properties of thin calcium-phosphate coatings formed by radio-frequency magnetron sputtering of a solid target made from hydroxyapatite on the surface of the thermoplastic copolymer of vinilidene fluoride and tetrafluoroethylene (VDF–TeFE) were investigated. Atomic force microscopy energy dispersive analysis and optical goniometry showed that deposited calcium-phosphate coatings change significantly the morphological, electrical, chemical, and contact properties of the surface of the initial polymeric substrates. These modified surfaces widen the scope of medical application of the thermoplastic copolymer.

  9. Silicalite-1 zeolite membranes on unmodified and modified surfaces

    Indian Academy of Sciences (India)

    Silicalite-1 zeolite membranes were prepared hydrothermally on the porous ceramic supports, both unmodified and modified with 3-aminopropyl triethoxysilane (APTES) as a coupling agent following ex situ (secondary) crystal growth process. The microstructure of the membranes was examined by scanning electron ...

  10. Surface-modified bacterial nanofibrillar PHB scaffolds for bladder tissue repair.

    Science.gov (United States)

    Karahaliloğlu, Zeynep; Demirbilek, Murat; Şam, Mesut; Sağlam, Necdet; Mızrak, Alpay Koray; Denkbaş, Emir Baki

    2016-01-01

    The aim of the study is in vitro investigation of the feasibility of surface-modified bacterial nanofibrous poly [(R)-3-hydroxybutyrate] (PHB) graft for bladder reconstruction. In this study, the surface of electrospun bacterial PHB was modified with PEG- or EDA via radio frequency glow discharge method. After plasma modification, contact angle of EDA-modified PHB scaffolds decreased from 110 ± 1.50 to 23 ± 0.5 degree. Interestingly, less calcium oxalate stone deposition was observed on modified PHB scaffolds compared to that of non-modified group. Results of this study show that surface-modified scaffolds not only inhibited calcium oxalate growth but also enhanced the uroepithelial cell viability and proliferation.

  11. A comparative study of the effectiveness of early and delayed loading of short tissue-level dental implants with hydrophilic surfaces placed in the posterior section of the mandible-A preliminary study.

    Science.gov (United States)

    Makowiecki, Arkadiusz; Botzenhart, Ute; Seeliger, Julia; Heinemann, Friedhelm; Biocev, Peter; Dominiak, Marzena

    2017-07-01

    The objective of the present study was to compare the primary and secondary stability of tissue-level short dental titanium implants with polished necks and hydrophilic surfaces of two different designs and manufacturers. The first implant system used (SPI ® ELEMENT RC INICELL titanium implants, Thommen Medical AG, Grenchen, Switzerland), allowed functional loading 6 weeks after its placement, whereas the second implant system (RN SLActiv ® tissue-level titanium implants, Straumann GmbH, Fribourg, Germany), was loaded after 15 weeks. The degree of primary and secondary stability was determined using an Osstell ISQ measuring device. Marginal bone loss (MBL) was evaluated radiographically 12 and 24 weeks after implantation and the Wachtel's healing index as well as the patient's satisfaction with the treatment was registered on a VAS scale. The intergroup comparison revealed significant differences in terms of primary stability as well as differences in MBL 3 months after the procedure, but no significant differences could be found after 6 months and for secondary stability. The primary stability was significantly higher for Thommen ® compared to Straumann ® implants. Insertion of short dental implants with a hydrophilic conditioned surface significantly shortens patient treatment time. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Influence of the surface structure on the filtration performance of UV-modified PES membranes

    DEFF Research Database (Denmark)

    Kæselev, Bozena Alicja; Kingshott, P.; Jonsson, Gunnar Eigil

    2002-01-01

    chemically characterised using X-ray photoelectron spectroscopy (XPS) and time of flight-static secondary ion mass spectrometry (TOF-static SIMS). The filtration performance of irradiated/non-modified and irradiated/modified membranes was examined in a crossflow cell, using a dextran solution. The filtration...... in relation to dextran when compared to membranes modified by AAG and AAP. This work suggests that the structure of the presence of grafted chains seems to be responsible for the observed changes to filtration performance of the modified membrane. Surface analysis supports the claim that the specific surface...

  13. Surfactant-assisted water exposed electrospinning of novel super hydrophilic polycaprolactone based fibers.

    Science.gov (United States)

    Zargarian, S Sh; Haddadi-Asl, V

    2017-08-01

    Hybrid scaffolds prepared by blend electrospinning of Polycaprolactone and Pluronic solution benefit from enhanced fiber hydrophilicity and may offer satisfactory cell attachment and proliferation. To improve hybrid scaffold wettability and water swelling ratio, adequate amount of hydrophilic polymer is required; though this amount is limited by fiber surface enrichment of Pluronic and cannot be exceeded without affecting the scaffold mechanical properties. To overcome this problem, a routine blend electrospinning setup was modified by exposing the blend solution to water in order to attract Pluronic chains toward the surface of the charged jet. Morphology of scaffolds produced by the routine blend electrospinning and modified method was studied. A 50 nm thick Pluronic layer with linty appearance on the surface of the fibers fabricated by the modified method was detected. Drug-loaded fibers from modified method showed a moderate initial burst and then a prolonged release period while an abnormal two-stage phased release profile was observed for the routine blend method. The latter was associated to Pluronic/drug accumulations within the fibers fabricated by the routine method which resulted in fiber disintegration and a subsequent second burst release.

  14. Copper hexacyanoferrate formation on the modified silica surface with DAB-Am-16 dendrimer

    International Nuclear Information System (INIS)

    Carmo, Devaney R. do; Gabriel Junior, Suelino; Bicalho, Urquisa O.; Paim, Leonardo L.

    2009-01-01

    The dendrimer hexadecamine poly(propylene)imine (DAB-Am-16) of third generation (G-3) was anchored on the silica gel surface. The modified silica interact easily with Cu 2+ and then with hexacyanoferrate to form copper hexacyanoferrate. The modified silica was characterized by following techniques: nuclear magnetic resonance (NMR), infrared (FTIR), energy dispersive X-ray (EDX) and cyclic voltammetry. As application of the composite obtained, the modified silica containing copper hexacyanoferrate (CuHCFSD) was tested for a voltammetric determination of nitrite using a graphite paste modified electrode. The modified graphite paste electrode can be applied also to the determination of others biological substances with success. (author)

  15. Effects of hydrophilic solvent and oxidation resistance post surface treatment on molecular structure and forward osmosis performance of polyamide thin-film composite (TFC) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Qibo; Xu, Yangyu [School of Environment, Tsinghua University, Beijing 100084 (China); Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Haijun, E-mail: yanghj@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhou, Lu, E-mail: zhoulu@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-11-30

    Graphical abstract: - Highlights: • NMP promotes swelling of polyamide, which enhances the TFC FO membrane water flux. • Electron-withdrawing carboxyl groups reduce the activity of polyamide molecules. • TMC and oxalic acid can improve the oxidation resistance properties of the FO membrane. • Oxalic acid and EDC improve the FO membrane separation performance significantly. - Abstract: In this article, novel hydrophilic solvents and antioxidants were used to post-treat aromatic polyamide thin-film composite (TFC) hollow fiber forward osmosis (FO) membranes. The effects of trimesoyl chloride (TMC) and oxalic acid on the structure of polyamide skin layer were investigated using ATR-FTIR and XPS analyses. Pure water flux and rejection of salts were detected using 2 M NaCl solution as draw solutions in FO processes. The results demonstrated that hydrophilic solvent N-methyl pyrrolidone (NMP) enhanced the water flux and kept a high salt retention of the TFC FO membrane. TMC and oxalic acid were both found to improve the oxidation resistance properties of the skin layer of TFC membrane because the electron-withdrawing carboxyl groups reduced the activity of polyamide molecular. The effects of the oxalic acid and carbodiimide on the molecular structures and the FO water flux of the polyamide TFC membranes were more marked than those of TMC. The novel TFC FO membrane treated by oxalic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) exhibited a high level of water flux (20.33 L m{sup −2} h{sup −1}), and the rates of salt rejection and salt reverse rejection were higher by 50% and 83%, respectively.

  16. Surface characterization of silver and palladium modified glassy ...

    Indian Academy of Sciences (India)

    WINTEC

    The morphology of metal coatings was characterized by ... face of sample containing the highest quantity of surface oxide complexes. It has been concluded that ..... Environment Protection of the Republic of Serbia for financial support.

  17. Crystal Nucleation Using Surface-Energy-Modified Glass Substrates.

    Science.gov (United States)

    Nordquist, Kyle A; Schaab, Kevin M; Sha, Jierui; Bond, Andrew H

    2017-08-02

    Systematic surface energy modifications to glass substrates can induce nucleation and improve crystallization outcomes for small molecule active pharmaceutical ingredients (APIs) and proteins. A comparatively broad probe for function is presented in which various APIs, proteins, organic solvents, aqueous media, surface energy motifs, crystallization methods, form factors, and flat and convex surface energy modifications were examined. Replicate studies ( n ≥ 6) have demonstrated an average reduction in crystallization onset times of 52(4)% (alternatively 52 ± 4%) for acetylsalicylic acid from 91% isopropyl alcohol using two very different techniques: bulk cooling to 0 °C using flat surface energy modifications or microdomain cooling to 4 °C from the interior of a glass capillary having convex surface energy modifications that were immersed in the solution. For thaumatin and bovine pancreatic trypsin, a 32(2)% reduction in crystallization onset times was demonstrated in vapor diffusion experiments ( n ≥ 15). Nucleation site arrays have been engineered onto form factors frequently used in crystallization screening, including microscope slides, vials, and 96- and 384-well high-throughput screening plates. Nucleation using surface energy modifications on the vessels that contain the solutes to be crystallized adds a layer of useful variables to crystallization studies without requiring significant changes to workflows or instrumentation.

  18. Chemical switches and logic gates based on surface modified semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Szacilowski; Wojciech, Macyk [Jagiellonian Univ., Dept. of Chemistry, Krakow (Poland)

    2006-02-15

    Photoelectrochemical properties of multicomponent photo-electrodes based on titanium dioxide and cadmium sulfide powders modified with hexacyanoferrate complexes have been examined. Photocurrent responses were recorded as functions of applied potential and photon energy. Surprisingly, the photocurrent can be switched between positive and negative values as a result of potential or photon energy changes. This new effect called Photo Electrochemical Photocurrent Switching (PEPS) opens a possibility of new chemical switches and logic gates construction. Boolean logic analysis and a tentative mechanism of the device are discussed. (authors)

  19. Stem cell responses to plasma surface modified electrospun polyurethane scaffolds.

    Science.gov (United States)

    Zandén, Carl; Hellström Erkenstam, Nina; Padel, Thomas; Wittgenstein, Julia; Liu, Johan; Kuhn, H Georg

    2014-07-01

    The topographical effects from functional materials on stem cell behavior are currently of interest in tissue engineering and regenerative medicine. Here we investigate the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell (hESC) and rat postnatal neural stem cell (NSC) responses. The plasma gases were found to induce three combinations of fiber surface functionalities and roughness textures. On randomly oriented fibers, plasma treatments lead to substantially increased hESC attachment and proliferation as compared to native fibers. Argon plasma was found to induce the most optimal combination of surface functionality and roughness for cell expansion. Contact guided migration of cells and alignment of cell processes were observed on aligned fibers. Neuronal differentiation around 5% was found for all samples and was not significantly affected by the induced variations of surface functional group distribution or individual fiber topography. In this study the influence of argon, oxygen, and hydrogen plasma surface modification of electrospun polyurethane fibers on human embryonic stem cell and rat postnatal neural stem cell (NSC) responses is studied with the goal of clarifying the potential effects of functional materials on stem cell behavior, a topic of substantial interest in tissue engineering and regenerative medicine. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Differential Expression of Osteo-Modulatory Molecules in Periodontal Ligament Stem Cells in Response to Modified Titanium Surfaces

    Directory of Open Access Journals (Sweden)

    So Yeon Kim

    2014-01-01

    Full Text Available This study assessed differential gene expression of signaling molecules involved in osteogenic differentiation of periodontal ligament stem cells (PDLSCs subjected to different titanium (Ti surface types. PDLSCs were cultured on tissue culture polystyrene (TCPS, and four types of Ti discs (PT, SLA, hydrophilic PT (pmodPT, and hydrophilic SLA (modSLA with no osteoinductive factor and then osteogenic activity, including alkaline phosphatase (ALP activity, mRNA expression of runt-related gene 2, osterix, FOSB, FRA1, and protein levels of osteopontin and collagen type IA, were examined. The highest osteogenic activity appeared in PDLSCs cultured on SLA, compared with the TCPS and other Ti surfaces. The role of surface properties in affecting signaling molecules to modulate PDLSC behavior was determined by examining the regulation of Wnt pathways. mRNA expression of the canonical Wnt signaling molecules, Wnt3a and β-catenin, was higher on SLA and modSLA than on smooth surfaces, but gene expression of the calcium-dependent Wnt signaling molecules Wnt5a, calmodulin, and NFATc1 was increased significantly on PT and pmodPT. Moreover, integrin α2/β1, sonic hedgehog, and Notch signaling molecules were affected differently by each surface modification. In conclusion, surface roughness and hydrophilicity can affect differential Wnt pathways and signaling molecules, targeting the osteogenic differentiation of PDLSCs.

  1. Long-term stability of superhydrophilic oxygen plasma-modified single-walled carbon nanotube network surfaces and the influence on ammonia gas detection

    Energy Technology Data Exchange (ETDEWEB)

    Min, Sungjoon [Department of Biomicrosystem Technology, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Joonhyub [Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-ro, Sejong City 339-770 (Korea, Republic of); Park, Chanwon [Department of Electrical and Electronic Engineering, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Jin, Joon-Hyung, E-mail: jj1023@chol.com [Department of Chemical Engineering, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16227 (Korea, Republic of); Min, Nam Ki, E-mail: nkmin@korea.ac.kr [Department of Biomicrosystem Technology, Korea University, Seoul 136-713 (Korea, Republic of)

    2017-07-15

    Graphical abstract: Superhydrophilic single-walled carbon nanotube obtained by O{sub 2} plasma treatment voluntarily and non-reversibly reverts to a metastable state. This aerobic aging is an essential process to develop a stable carbon nanotube-based sensor. - Highlights: • Superhydrophilic single-walled carbon nanotube network can be obtained by O{sub 2} plasma-based surface modification. • The modified carbon nanotube surface invariably reverts to a metastable state in a non-reversible manner. • Aerobic aging is essential to stabilize the modified carbon nanotube and the carbon nanotube-based sensing device due to minimized sensor-to-sensor variation. - Abstract: Single-walled carbon nanotube (SWCNT) networks are subjected to a low-powered oxygen plasma for the surface modification. Changes in the surface chemical composition and the stability of the plasma-treated SWCNT (p-SWCNT) with aging in air for up to five weeks are studied using X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The contact angle decreases from 120° of the untreated hydrophobic SWCNT to 0° for the superhydrophilic p-SWCNT. Similarly, the ratio of oxygen to carbon (O:C) based on the XPS spectra increases from 0.25 to 1.19, indicating an increase in surface energy of the p-SWCNT. The enhanced surface energy is gradually dissipated and the p-SWCNT network loses the superhydrophilic surface property. However, it never revert to the original hydrophobic surface state but to a metastable hydrophilic state. The aging effect on sensitivity of the p-SWCNT network-based ammonia sensor is investigated to show the importance of the aging process for the stabilization of the p-SWCNT. The best sensitivity for monitoring NH{sub 3} gas is observed with the as-prepared p-SWCNT, and the sensitivity decreases as similar as the p-SWCNT loses its hydrophilicity with time goes by. After a large performance degradation during the aging time for about two weeks, the response

  2. Structure–Property Relationships of Inorganically Surface-Modified Zeolite Molecular Sieves for Nanocomposite Membrane Fabrication

    KAUST Repository

    Lydon, Megan E.; Unocic, Kinga A.; Bae, Tae-Hyun; Jones, Christopher W.; Nair, Sankar

    2012-01-01

    A multiscale experimental study of the structural, compositional, and morphological characteristics of aluminosilicate (LTA) and pure-silica (MFI) zeolite materials surface-modified with MgO xH y nanostructures is presented. These characteristics

  3. Efficiency of surface modified Ti coated with copper nanoparticles to ...

    Indian Academy of Sciences (India)

    environment which in turn affects the efficiency of the metal. To reduce the ... The microbial adhesion on the surface of Ti, TiO2-NTs and NT-CuNP coupons were ... applications from water and air purification to tissue engi- neering and ...

  4. Modified hot-conditioning of PHT system surfaces of PHWRs

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswaran, G [Bhabha Atomic Research Centre, Trombay, Bombay (India)

    1997-02-01

    The increased awareness on the importance of controlling activity transport and radiation buildup on out-of-core surfaces of water cooled nuclear reactors is leading to a host of measures both from chemistry as well as engineering sides being undertaken. Passivation of the surfaces of structural materials is one such. Pressurised Heavy Water Reactors of CANDU design use large surface area of carbon steel alloy in the Primary Heat Transport System. Hot-conditioning of the PHT system with deoxygenated light water at temperatures {approx_equal} 473 - 523 K during commissioning stage is done to form a protective magnetite film on the surfaces of carbon steel essentially to guard this material from corrosion during the intervening period between initial commissioning and first fuel loading and achieving nuclear heat. However, a need is felt to improve the quality of this magnetite film and control the crud release so that the twin objectives of controlling the corrosion of carbon steel and reducing a possible deposition of corrosion products on surfaces of fuel clad could be achieved. Laboratory static autoclave investigations have been carried out on the formation of protective magnetite film on carbon steel at 473 K, pH 10 (pH at 298 K) deoxygenated aqueous solutions of chelants like HEDTA, DTPA, NTA apart from EDTA. Additionally, influence of AVT chemicals like hydrazine, cyclohexylamine, morpholine and additives like glucose, boric acid has been studied. The data have been compared with the standard procedure of hot-conditioning namely with simple LiOH. It is found that chelants increase the base metal loss but the oxide formed is more protective than the one formed under simple LiOH treatment. The efficiency of passivation is greatly enhanced by hydrazine and boric acid while it is adversely affected by glucose. AVT chemicals acts as effective corrosion inhibitors. (author). 14 refs, 2 figs, 4 tabs.

  5. Modified hot-conditioning of PHT system surfaces of PHWRs

    International Nuclear Information System (INIS)

    Venkateswaran, G.

    1997-01-01

    The increased awareness on the importance of controlling activity transport and radiation buildup on out-of-core surfaces of water cooled nuclear reactors is leading to a host of measures both from chemistry as well as engineering sides being undertaken. Passivation of the surfaces of structural materials is one such. Pressurised Heavy Water Reactors of CANDU design use large surface area of carbon steel alloy in the Primary Heat Transport System. Hot-conditioning of the PHT system with deoxygenated light water at temperatures ≅ 473 - 523 K during commissioning stage is done to form a protective magnetite film on the surfaces of carbon steel essentially to guard this material from corrosion during the intervening period between initial commissioning and first fuel loading and achieving nuclear heat. However, a need is felt to improve the quality of this magnetite film and control the crud release so that the twin objectives of controlling the corrosion of carbon steel and reducing a possible deposition of corrosion products on surfaces of fuel clad could be achieved. Laboratory static autoclave investigations have been carried out on the formation of protective magnetite film on carbon steel at 473 K, pH 10 (pH at 298 K) deoxygenated aqueous solutions of chelants like HEDTA, DTPA, NTA apart from EDTA. Additionally, influence of AVT chemicals like hydrazine, cyclohexylamine, morpholine and additives like glucose, boric acid has been studied. The data have been compared with the standard procedure of hot-conditioning namely with simple LiOH. It is found that chelants increase the base metal loss but the oxide formed is more protective than the one formed under simple LiOH treatment. The efficiency of passivation is greatly enhanced by hydrazine and boric acid while it is adversely affected by glucose. AVT chemicals acts as effective corrosion inhibitors. (author). 14 refs, 2 figs, 4 tabs

  6. Multilayer Choline Phosphate Molecule Modified Surface with Enhanced Cell Adhesion but Resistance to Protein Adsorption.

    Science.gov (United States)

    Chen, Xingyu; Yang, Ming; Liu, Botao; Li, Zhiqiang; Tan, Hong; Li, Jianshu

    2017-08-22

    Choline phosphate (CP), which is a new zwitterionic molecule, and has the reverse order of phosphate choline (PC) and could bind to the cell membrane though the unique CP-PC interaction. Here we modified a glass surface with multilayer CP molecules using surface-initiated atom-transfer radical polymerization (SI-ATRP) and the ring-opening method. Polymeric brushes of (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by SI-ATRP from the glass surface. Then the grafted PDMAEMA brushes were used to introduce CP groups to fabricate the multilayer CP molecule modified surface. The protein adsorption experiment and cell culture test were used to evaluate the biocompatibility of the modified surfaces by using human umbilical veinendothelial cells (HUVECs). The protein adsorption results demonstrated that the multilayer CP molecule decorated surface could prevent the adsorption of fibrinogen and serum protein. The adhesion and proliferation of cells were improved significantly on the multilayer CP molecule modified surface. Therefore, the biocompatibility of the material surface could be improved by the modified multilayer CP molecule, which exhibits great potential for biomedical applications, e.g., scaffolds in tissue engineering.

  7. Characterization of Modified and Polymer Coated Alumina Surfaces by Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ashraf Yehia El-Naggar

    2013-01-01

    Full Text Available The prepared, modified, and coated alumina surfaces were characterized by infrared spectroscopy (FTIR to investigate the surface properties of the individual and double modified samples. FTIR helps in reporting the changes occurred in hydroxyl groups as well as the structure changes as a result of thermal treating, hydrothermal treating, silylation treating, alkali metal treating, coating, and bonding with polymer. FTIR spectroscopy represents the strength and abundance of surface acidic OH which determine the adsorption properties of polar and nonpolar sorbents. Generally, all treated samples exhibit decrease of OH groups compared with those of parent ones producing alumina surfaces of different adsorptive powers.

  8. Modified expression of surface glyconjugates in stored human platelets

    International Nuclear Information System (INIS)

    Dhar, A.; Ganguly, P.

    1987-01-01

    Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4 0 or 22 0 and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with 3 H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets

  9. Modified expression of surface glyconjugates in stored human platelets

    Energy Technology Data Exchange (ETDEWEB)

    Dhar, A.; Ganguly, P.

    1987-05-01

    Platelets are anucleated cells which play an important part in blood coagulation and thrombosis. These cells may be stored in the blood bank for only 4/5 days. In order to improve the storage of platelets, it is essential to first understand the changes in these cells due to storage. In this work, human platelets were stored in autologous plasma at 4/sup 0/ or 22/sup 0/ and their surface changes were monitored with three lectins - wheat germ afflutinin (WGA), concanavalin A (Con A) and lentil lectin (LL). Blood was drawn from healthy donors and platelet rich plasma (PRP) was collected by slow speed centrifugation. Platelets stored at either temperature for different times showed increased sensitivity to agglutination by WGA after 34-48 hrs. Lectins, Con A and LL, which were not agglutinating to fresh platelets readily caused agglutination after 48-72 hrs. The platelets stored for 25 hrs or longer period were insensitive to thrombin but showed enhanced aggregation with WGA. Labelling of surface glycoconjugates of stored platelets with /sup 3/H-boro-hydride revealed progressive loss of a glycoprotein of Mr 150,000 (GPIb infinity) together with the appearance of components of Mr 69,000; Mr 60,000; Mr 25,000. New high molecular weight glycoproteins were also detected only in stored platelets. The author studies clearly indicate that modification or altered expression of platelets surface glycoproteins may be one factor of storage related dysfunction of platelets.

  10. Surface-modified polymers for cardiac tissue engineering.

    Science.gov (United States)

    Moorthi, Ambigapathi; Tyan, Yu-Chang; Chung, Tze-Wen

    2017-09-26

    Cardiovascular disease (CVD), leading to myocardial infarction and heart failure, is one of the major causes of death worldwide. The physiological system cannot significantly regenerate the capabilities of a damaged heart. The current treatment involves pharmacological and surgical interventions; however, less invasive and more cost-effective approaches are sought. Such new approaches are developed to induce tissue regeneration following injury. Hence, regenerative medicine plays a key role in treating CVD. Recently, the extrinsic stimulation of cardiac regeneration has involved the use of potential polymers to stimulate stem cells toward the differentiation of cardiomyocytes as a new therapeutic intervention in cardiac tissue engineering (CTE). The therapeutic potentiality of natural or synthetic polymers and cell surface interactive factors/polymer surface modifications for cardiac repair has been demonstrated in vitro and in vivo. This review will discuss the recent advances in CTE using polymers and cell surface interactive factors that interact strongly with stem cells to trigger the molecular aspects of the differentiation or formulation of cardiomyocytes for the functional repair of heart injuries or cardiac defects.

  11. The Au modified Ge(1 1 0) surface

    Science.gov (United States)

    Zhang, L.; Kabanov, N. S.; Bampoulis, P.; Saletsky, A. M.; Zandvliet, H. J. W.; Klavsyuk, A. L.

    2018-05-01

    The pristine Ge(1 1 0) surface is composed of Ge pentagons, which are arranged in relatively large (16 × 2) and c(8 × 10) unit cells. The deposition of sub-monolayer amounts of Au and mild annealing results into de-reconstructed Ge(1 1 0) regions completely free of Ge pentagons and regions composed of nanowires that are aligned along the high symmetry [ 1 1 bar 0 ] direction of the Ge(1 1 0) surface. The de-reconstructed Ge(1 1 0) regions consist of atomic rows that are aligned along the [ 1 1 bar 0 ] direction. A substantial fraction of these substrate rows are straight and resemble the atom rows of the unreconstructed, i.e. bulk terminated, Ge(1 1 0) surface, whereas the other substrate rows have a meandering appearance. These meandering atom rows are comprised of two types of atoms, one type that appears dim, whereas the other type appears bright in filled-state scanning tunneling microscopy images. Using density functional theory calculations, we have tested more than 20 different atomic models for the meandering atom rows. The density functional theory calculations reveal that it is energetically favorable for the deposited Au atoms to exchange position with Ge atoms in the first layer. Based on these findings we conclude that the bright atoms are Ge atoms, whereas the dim atoms are Au atoms.

  12. Surface modification of fluorosilicone acrylate RGP contact lens via low-temperature argon plasma

    International Nuclear Information System (INIS)

    Yin Shiheng; Wang Yingjun; Ren Li; Zhao Lianna; Kuang Tongchun; Chen Hao; Qu Jia

    2008-01-01

    A fluorosilicone acrylate rigid gas permeable (RGP) contact lens was modified via argon plasma to improve surface hydrophilicity and resistance to protein deposition. The influence of plasma treatment on surface chemical structure, hydrophilicity and morphology of RGP lens was investigated by X-ray photoelectron spectrometer (XPS), contact angle measurements and scanning electron microscope (SEM), respectively. The contact angle results showed that the hydrophilicity of the contact lens was improved after plasma treatment. XPS results indicated that the incorporation of oxygen-containing groups on surface and the transformation of silicone into hydrophilic silicate after plasma treatment are the main reasons for the surface hydrophilicity improvement. SEM results showed that argon plasma with higher power could lead to surface etching

  13. Growth of pentacene on clean and modified gold surfaces

    International Nuclear Information System (INIS)

    Kaefer, Daniel; Ruppel, Lars; Witte, Gregor

    2007-01-01

    The growth and evolution of pentacene films on gold substrates have been studied. By combining complementary techniques including scanning tunneling microscopy, atomic force microscopy, scanning electron microscopy, near-edge x-ray-absorption fine structure, and x-ray diffraction, the molecular orientation, crystalline structure, and morphology of the organic films were characterized as a function of film thickness and growth parameters (temperature and rate) for different gold substrates ranging from Au(111) single crystals to polycrystalline gold. Moreover, the influence of precoating the various gold substrates with self-assembled monolayers (SAM's) of organothiols with different chemical terminations has been studied. On bare gold the growth of pentacene films is characterized by a pronounced dewetting while the molecular orientation within the resulting crystalline three-dimensional islands depends distinctly on the roughness and cleanliness of the substrate surface. After completion of the first wetting layer where molecules adopt a planar orientation parallel to the surface the molecules continue to grow in a tilted fashion: on Au(111) the long molecular axis is oriented parallel to the surface while on polycrystalline gold it is upstanding oriented and thus parallels the crystalline orientation of pentacene films grown on SiO 2 . On SAM pretreated gold substrates the formation of a wetting layer is effectively suppressed and pentacene grows in a quasi-layer-by-layer fashion with an upstanding orientation leading to rather smooth films. The latter growth mode is observed independently of the chemical termination of the SAM's and the roughness of the gold substrate. Possible reasons for the different growth mechanism as well as consequences for the assignment of spectroscopic data of thin pentacene film are discussed

  14. SURFACE MODIFICATIONS WITH LASER SYNTHESIZED Mo MODIFIED COATING

    OpenAIRE

    LU SUN; HAO CHEN; BO LIU

    2013-01-01

    Mg–Cu–Al was first used to improve the surface performance of TA15 titanium alloys by means of laser cladding technique. The synthesis of hard composite coating on TA15 titanium alloy by laser cladding of Mg–Cu–Al–B4C/Mo pre-placed powders was investigated by means of scanning electron microscope, energy dispersive spectrometer and high resolution transmission electron microscope. Experimental results indicated that such composite coating mainly consisted of TiB2, TiB, TiC, Ti3Al and AlCuMg. ...

  15. Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles

    Science.gov (United States)

    Remes, Z.; Kozak, H.; Rezek, B.; Ukraintsev, E.; Babchenko, O.; Kromka, A.; Girard, H. A.; Arnault, J.-C.; Bergonzo, P.

    2013-04-01

    Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000-1500 cm-1 spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.

  16. Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Remes, Z., E-mail: remes@fzu.cz [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Kozak, H.; Rezek, B.; Ukraintsev, E.; Babchenko, O.; Kromka, A. [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Girard, H.A.; Arnault, J.-C.; Bergonzo, P. [CEA, LIST, Diamond Sensors Laboratory, F-91191 Gif-sur-Yvette (France)

    2013-04-01

    Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000–1500 cm{sup −1} spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.

  17. Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

    Science.gov (United States)

    Ji, Min-Kyung; Lee, Min-Joo; Park, Sang-Won; Lee, Kwangmin; Yun, Kwi-Dug; Kim, Hyun-Seung; Oh, Gye-Jeong; Kim, Ji-Hyun; Lim, Hyun-Pil

    2016-02-01

    The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans.

  18. Surface Modifications with Laser Synthesized Mo Modified Coating

    Science.gov (United States)

    Sun, Lu; Chen, Hao; Liu, Bo

    2013-01-01

    Mg-Cu-Al was first used to improve the surface performance of TA15 titanium alloys by means of laser cladding technique. The synthesis of hard composite coating on TA15 titanium alloy by laser cladding of Mg-Cu-Al-B4C/Mo pre-placed powders was investigated by means of scanning electron microscope, energy dispersive spectrometer and high resolution transmission electron microscope. Experimental results indicated that such composite coating mainly consisted of TiB2, TiB, TiC, Ti3Al and AlCuMg. Compared with TA15 alloy substrate, an improvement of wear resistance was observed for this composite coating due to the actions of fine grain, amorphous and hard phase strengthening.

  19. High Efficiency Acetylcholinesterase Immobilization on DNA Aptamer Modified Surfaces

    Directory of Open Access Journals (Sweden)

    Orada Chumphukam

    2014-04-01

    Full Text Available We report here the in vitro selection of DNA aptamers for electric eel acetylcholinesterase (AChE. One selected aptamer sequence (R15/19 has a high affinity towards the enzyme (Kd = 157 ± 42 pM. Characterization of the aptamer showed its binding is not affected by low ionic strength (~20 mM, however significant reduction in affinity occurred at high ionic strength (~1.2 M. In addition, this aptamer does not inhibit the catalytic activity of AChE that we exploit through immobilization of the DNA on a streptavidin-coated surface. Subsequent immobilization of AChE by the aptamer results in a 4-fold higher catalytic activity when compared to adsorption directly on to plastic.

  20. Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

    International Nuclear Information System (INIS)

    Kim, Hyungmo; Kim, Joonwon

    2010-01-01

    This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

  1. Ligation-based mutation detection and RCA in surface un-modified OSTE+ polymer microfluidic chambers

    DEFF Research Database (Denmark)

    Saharil, Farizah; Ahlford, Annika; Kuhnemund, Malte

    2013-01-01

    For the first time, we demonstrate DNA mutation detection in surface un-modified polymeric microfluidic chambers without suffering from bubble trapping or bubble formation. Microfluidic devices were manufactured in off-stoichiometry thiol-ene epoxy (OSTE+) polymer using an uncomplicated and rapid...... during bio-operation at elevated temperatures. In contrast, PMMA, PDMS and COP microfluidic devices required specific surface treatment....

  2. Hierarchical micro-nano structured Ti6Al4V surface topography via two-step etching process for enhanced hydrophilicity and osteoblastic responses.

    Science.gov (United States)

    Moon, Byeong-Seok; Kim, Sungwon; Kim, Hyoun-Ee; Jang, Tae-Sik

    2017-04-01

    Hierarchical micro-nano (HMN) surface structuring of dental implants is a fascinating strategy for achieving fast and mechanically stable fixation due to the synergetic effect of micro- and nano-scale surface roughness with surrounding tissues. However, the introduction of a well-defined nanostructure on a microstructure having complex surface geometry is still challenging. As a means of fabricating HMN surface on Ti6Al4V-ELI, target-ion induced plasma sputtering (TIPS) was used onto a sand-blasted, large-grit and acid-etched substrate. The HMN surface topography was simply controlled by adjusting the tantalum (Ta) target power of the TIPS technique, which is directly related to the Ta ion flux and the surface chemical composition of the substrate. Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser scanning microscopy (LSM) verified that well-defined nano-patterned surface structures with a depth of ~300 to 400nm and a width of ~60 to 70nm were uniformly distributed and followed the complex micron-sized surface geometry. In vitro cellular responses of pre-osteoblast cells (MC3T3-E1) were assessed by attachment and proliferation of cells on flat, nano-roughened, micro-roughened, and an HMN surface structure of Ti6Al4V-ELI. Moreover, an in vivo dog mandible defect model study was used to investigate the biological effect of the HMN surface structure compared with the micro-roughened surface. The results showed that the surface nanostructure significantly increased the cellular activities of flat and micro-roughened Ti, and the bone-to-implant contact area and new bone volume were significantly improved on the HMN surface structured Ti. These results support the idea that an HMN surface structure on Ti6Al4V-ELI alloy has great potential for enhancing the biological performance of dental implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Surface modified alginate microcapsules for 3D cell culture

    Science.gov (United States)

    Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

    2016-06-01

    Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

  4. Sorption of nonpolar aromatic contaminants by chlorosilane surface modified natural minerals.

    Science.gov (United States)

    Huttenloch, P; Roehl, K E; Czurda, K

    2001-11-01

    The efficacy of the surface modification of natural diatomite and zeolite material by chlorosilanes is demonstrated. Chlorosilanes used were trimethylchlorosilane (TMSCI), tert-butyldimethylchlorosilane (TBDMSCI), dimethyloctadecylchlorosilane (DMODSCI), and diphenyldichlorosilane (DPDSCI) possessing different headgroups and chemical properties. Silanol groups of the diatomite and zeolite were modified by chemical reaction with the chlorosilanes resulting in a stable covalent attachment of the organosilanes to the mineral surface. The alteration of surface properties of the modified material was proved by measurements of water adsorption capacity, total organic carbon (TOC) content, and thermoanalytical data. The surface modified material showed great stability even when exposed to extremes in ionic strength, pH, and to pure organic solvents. Sorption of toluene, o-xylene, and naphthalene from water was greatly enhanced by the surface modification compared to the untreated materials which showed no measurable sorption of these compounds. The enhanced sorption was dependent on the organic carbon content as well as on chemical characteristics of the chlorosilanes used. Batch sorption experiments showed that the phenyl headgroups of DPDSCI have the best affinity for aromatic compounds. Removal from an aqueous solution of 10 mg/L of naphthalene, o-xylene, and toluene was 71%, 60%, and 30% for surface modified diatomite and 51%, 30%, and 16% for modified clinoptilolite, respectively. Sorption data were well described by the Freundlich isotherm equation, which indicated physical adsorption onto the lipophilic surface rather than partitioning into the surface organic phase. The chlorosilane modified materials have an apparent potential for application in environmental technologies such as permeable reactive barriers (PRB) or wastewater treatment.

  5. Electric treatment for hydrophilic ink deinking.

    Science.gov (United States)

    Du, Xiaotang; Hsieh, Jeffery S

    2017-09-01

    Hydrophilic inks have been widely used due to higher printing speed, competitive cost and being healthy non-organic solvents. However, they cause problems in both product quality and process runnability due to their hydrophilic surface wettability, strong negative surface charge and sub-micron size. Electric treatment was shown to be able to increase the ink sizes from 60 nm to 700 nm through electrocoagulation and electrophoresis. In addition, electric treatment assisted flotation could reduce effective residual ink concentration (ERIC) by 90 ppm, compared with only 20 ppm by traditional flotation. Furthermore, the effect of electric treatment alone on ink separation was investigated by two anode materials, graphite and stainless steel. Both of them could remove hydrophilic inks with less than 1% yield loss via electroflotation and electrophoresis. But graphite is a better material as the anode because graphite reduced ERIC by an additional 100 ppm. The yield loss of flotation following electric treatment was also lower by 17% if graphite was the anode material. The difference between the two electrode materials resulted from electrocoagulation and ink redeposition during electric treatment. An electric pretreatment-flotation-hyperwashing process was conducted to understand the deinking performance in conditions similar to a paper mill, and the ERIC was reduced from 950 ppm to less than 400 ppm.

  6. Radiation grafting of hydrophilic monomers on to plasticized poly(vinyl chloride) sheets: Pt. 1

    International Nuclear Information System (INIS)

    Kalliyana Krishnan, V.; Jayakrishnan, A.; Francis, J.D.

    1990-01-01

    Medical-grade plasticized polyvinyl chloride (PVC) sheets were surface modified using gamma-radiation grafting of a combination of hydrophilic monomers based on 2-hydroxyethyl methacrylate (HEMA) and N-vinyl pyrrolidone (NVP). The properties of the modified surfaces were evaluated using contact angle measurements, phase-contrast photomicroscopy and scanning electron microscopy. Surface energy calculations indicated that the surfaces became highly hydrophilic when grafted with even a 1% (v/v) solution of HEMA-NVP combination in the presence of 0.005 M CuSO 4 . Migration of the plasticizer di(2-ethylhexyl phthalate) from the grafted sheets was examined in hydrocarbon solvents such as n-hexane, n-heptane and n-octane and in extractant media such as cotton seed oil and polyethylene glycol-400 (PEG-400). The migration was found to be 0 C over a period of 5 h. Accelerated leaching studies in cotton seed oil and PEG-400 demonstrated that virtually no plasticizer migrated out in the former over a period of 96 h whereas the rate of migration in the latter medium showed only a mild reduction. The migration behaviour was Fickian in nature for grafted sheets. The method described may be useful as a simple, versatile technique for preventing plasticizer migration from plasticized PVC for medical applications. (author)

  7. Microstructure evolution and tribological properties of acrylonitrile-butadiene rubber surface modified by atmospheric plasma treatment

    Science.gov (United States)

    Shen, Ming-xue; Zhang, Zhao-xiang; Peng, Xu-dong; Lin, Xiu-zhou

    2017-09-01

    For the purpose of prolonging the service life for rubber sealing elements, the frictional behavior of acrylonitrile-butadiene rubber (NBR) surface by dielectric barrier discharge plasma treatments was investigated in this paper. Surface microstructure and chemical composition were measured by atomic force microscopy, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. Water contact angles of the modified rubber surface were also measured to evaluate the correlation between surface wettability and tribological properties. The results show that plasma treatments can improve the properties of the NBR against friction and wear effectively, the surface microstructure and roughness of plasma-modified NBR surface had an important influence on the surface tribological behavior, and the wear depth first decreased and then increased along with the change of plasma treatment time. It was found that the wettability of the modified surface was gradually improved, which was mainly due to the change of the chemical composition after the treatment. This study suggests that the plasma treatment could effectively improve the tribological properties of the NBR surface, and also provides information for developing wear-resistant NBR for industrial applications.

  8. SEM examination and analysis of the interface character in surface modified aramid-epoxy composite

    International Nuclear Information System (INIS)

    Hussain, S.; Khan, M.B.; Hussain, R.

    2011-01-01

    The surface of Kevlar fibers is chemically modified by treatment with Phthalic anhydride (PA) and the effect is examined by SEM for the laser cut, three point bending and interlaminar shear delaminated surfaces. The surface modification improved the adhesion to epoxy resin that clearly leads to cohesive fracture as opposed to interfacial failure in the untreated specimen. SEM reveals marginal surface roughening of fibers without compromising their strength. The interface modification technique described in this paper is attractive thermodynamically as it does not compromise surface free energy of the polymer matrix or that of the fiber itself to enhance wet ability. (author)

  9. Hydrophobically modified polyelectrolytes : synthesis, properties and interactions with surfactants

    NARCIS (Netherlands)

    Nieuwkerk, A.C.

    1998-01-01

    Hydrophobically modified polyelectrolytes can form micelle-like aggregates, so-called microdomains, in aqueous solution. The hydrophobic side chains constitute the apolar inner part of these microdomains and the hydrophilic groups on the polyelectrolyte backbone are at the surface of the

  10. Covalent attachment of phospholipid analogous polymers to modify a polymeric membrane surface: a novel approach.

    Science.gov (United States)

    Xu, Zhi-Kang; Dai, Qing-Wen; Wu, Jian; Huang, Xiao-Jun; Yang, Qian

    2004-02-17

    A novel method for the surface modification of a microporous polypropylene membrane by tethering phospholipid analogous polymers (PAPs) is given, which includes the photoinduced graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of grafted poly-(DMAEMA) with 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes. Five 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes, containing octyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy, and octadecyloxy groups in the molecular structure, were used to fabricate the PAP-modified polypropylene membranes. The attenuated total reflectance FT-IR spectra of the original, poly(DMAEMA)-grafted, and PAP-modified membranes confirmed the chemical changes on the membrane surface. Scanning electron microscope pictures showed that, compared with the original membrane, the surface porosities ofpoly(DMAEMA)-grafted and PAP-modified membranes were somewhat reduced. Water contact angles measured by the sessile drop method on PAP-modified membranes were slightly lower than that on the original polypropylene membrane, but higher than those on poly(DMAEMA)-grafted membranes with the exception of octyloxy-containing PAP-modified membranes. However, BSA adsorption experiments indicated that the five PAP-modified membranes had a much better protein-resistant property than the original polypropylene membrane and the poly(DMAEMA)-grafted membranes. For hexadecyloxy- and octadecyloxy-containing PAP-modified membranes, almost no protein adsorption was observed when the grafting degree was above 6 wt %. It was also found that the platelet adhesion was remarkably suppressed on the PAP-modified membranes. All these results demonstrate that the described approach is an effective way to improve the surface biocompatibility for polymeric membranes.

  11. Embroidered and surface modified polycaprolactone-co-lactide scaffolds as bone substitute: in vitro characterization.

    Science.gov (United States)

    Rentsch, Barbe; Hofmann, Andre; Breier, Annette; Rentsch, Claudia; Scharnweber, Dieter

    2009-10-01

    The aim of this study was to evaluate an embroidered polycaprolactone-co-lactide (trade name PCL) scaffold for the application in bone tissue engineering. The surface of the PCL scaffolds was hydrolyzed with NaOH and coated with collagen I (coll I) and chondroitin sulfate (CS). It was investigated if a change of the surface properties and the application of coll I and CS could promote cell adhesion, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSC). The porosity (80%) and pore size (0.2-1 mm) of the scaffold could be controlled by embroidery technique and should be suitable for bone ingrowth. The treatment with NaOH made the polymer surface more hydrophilic (water contact angle dropped to 25%), enhanced the coll I adsorption (up to 15%) and the cell attachment (two times). The coll I coated scaffold improved cell attachment and proliferation (three times). CS, as part of the artificial matrix, could induce the osteogenic differentiation of hMSC without other differentiation additives. The investigated scaffolds could act not just as temporary matrix for cell migration, proliferation, and differentiation in bone tissue engineering but also have a great potential as bioartificial bone substitute.

  12. Relationship between complement activation, cellular uptake and surface physicochemical aspects of novel PEG-modified nanocapsules.

    Science.gov (United States)

    Mosqueira, V C; Legrand, P; Gulik, A; Bourdon, O; Gref, R; Labarre, D; Barratt, G

    2001-11-01

    The aim of our work was to examine the relationship between modifications of the surface of nanocapsules (NC) by adsorption or covalent grafting of poly(ethylene oxide) (PEG), and changes in their phospholipid (PL) content on complement activation (C3 cleavage) and on uptake by macrophages. The physicochemical characterization of the NC included an investigation of their properties, such as surface charge, size, hydrophilicity, morphology and homogeneity. This is the first time that such properties have been correlated with biological interactions for NC, a novel carrier system with a structure more complex than nanospheres. C3 crossed immunoelectrophoresis revealed the reduced activation for NC with longer PEG chain and higher density, although all formulations induced C3 cleavage to a lesser or greater extent. NC bearing PEG covalently bound to the surface were weaker activators of complement than plain PLA [poly(D,L-lactide)] NC or nanospheres (NS). Furthermore, the fluorescent/confocal microscopy of J774A1 cells in contact with NC reveal a dramatically reduced interaction with PEG-bearing NC. However, the way in which PEG was attached (covalent or adsorbed) seemed to affect the mechanism of uptake. Taken together, these results suggest that the low level of protein binding to NC covered with a high density of 20kDa PEG chains is likely to be due to the steric barriers surrounding these particles, which prevents protein adsorption and reduces their interaction with macrophages.

  13. Effect of laser parameters on surface roughness of laser modified tool steel after thermal cyclic loading

    Science.gov (United States)

    Lau Sheng, Annie; Ismail, Izwan; Nur Aqida, Syarifah

    2018-03-01

    This study presents the effects of laser parameters on the surface roughness of laser modified tool steel after thermal cyclic loading. Pulse mode Nd:YAG laser was used to perform the laser surface modification process on AISI H13 tool steel samples. Samples were then treated with thermal cyclic loading experiments which involved alternate immersion in molten aluminium (800°C) and water (27°C) for 553 cycles. A full factorial design of experiment (DOE) was developed to perform the investigation. Factors for the DOE are the laser parameter namely overlap rate (η), pulse repetition frequency (f PRF) and peak power (Ppeak ) while the response is the surface roughness after thermal cyclic loading. Results indicate the surface roughness of the laser modified surface after thermal cyclic loading is significantly affected by laser parameter settings.

  14. Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

    Energy Technology Data Exchange (ETDEWEB)

    Varault, S. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9 (France); Gabard, B. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); STAE—4, Rue Emile Monso, BP84234, 31030 Toulouse Cedex 4 (France); Crépin, T.; Bolioli, S. [ONERA—The French Aerospace Lab 2, Avenue Edouard Belin, BP4025, 31055 Toulouse Cedex (France); Sokoloff, J. [Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9 (France)

    2014-02-28

    We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiation pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide.

  15. Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

    International Nuclear Information System (INIS)

    Varault, S.; Gabard, B.; Crépin, T.; Bolioli, S.; Sokoloff, J.

    2014-01-01

    We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiation pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide

  16. Evaluation of modified stainless steel surfaces targeted to reduce biofilm formation by common milk sporeformers.

    Science.gov (United States)

    Jindal, Shivali; Anand, Sanjeev; Huang, Kang; Goddard, Julie; Metzger, Lloyd; Amamcharla, Jayendra

    2016-12-01

    The development of bacterial biofilms on stainless steel (SS) surfaces poses a great threat to the quality of milk and other dairy products as the biofilm-embedded bacteria can survive thermal processing. Established biofilms offer cleaning challenges because they are resistant to most of the regular cleaning protocols. Sporeforming thermoduric organisms entrapped within biofilm matrix can also form heat-resistant spores, and may result in a long-term persistent contamination. The main objective of this study was to evaluate the efficacy of different nonfouling coatings [AMC 18 (Advanced Materials Components Express, Lemont, PA), Dursan (SilcoTek Corporation, Bellefonte, PA), Ni-P-polytetrafluoroethylene (PTFE, Avtec Finishing Systems, New Hope, MN), and Lectrofluor 641 (General Magnaplate Corporation, Linden, NJ)] on SS plate heat exchanger surfaces, to resist the formation of bacterial biofilms. It was hypothesized that modified SS surfaces would promote a lesser amount of deposit buildup and bacterial adhesion as compared with the native SS surface. Vegetative cells of aerobic sporeformers, Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599), were used to study biofilm development on the modified and native SS surfaces. The adherence of these organisms, though influenced by surface energy and hydrophobicity, exhibited no apparent relation with surface roughness. The Ni-P-PTFE coating exhibited the least bacterial attachment and milk solid deposition, and hence, was the most resistant to biofilm formation. Scanning electron microscopy, which was used to visualize the extent of biofilm formation on modified and native SS surfaces, also revealed lower bacterial attachment on the Ni-P-PTFE as compared with the native SS surface. This study thus provides evidence of reduced biofilm formation on the modified SS surfaces. Copyright © 2016 American Dairy Science Association. Published by Elsevier

  17. Acrylic acid surface-modified contact lens for the culture of limbal stem cells.

    Science.gov (United States)

    Zhang, Hong; Brown, Karl David; Lowe, Sue Peng; Liu, Guei-Sheung; Steele, David; Abberton, Keren; Daniell, Mark

    2014-06-01

    Surface treatment to a biomaterial surface has been shown to modify and help cell growth. Our aim was to determine the best surface-modified system for the treatment of limbal stem cell deficiency (LSCD), which would facilitate expansion of autologous limbal epithelial cells, while maintaining cultivated epithelial cells in a less differentiated state. Commercially available contact lenses (CLs) were variously surface modified by plasma polymerization with ratios of acrylic acid to octadiene tested at 100% acrylic acid, 50:50% acrylic acid:octadiene, and 100% octadiene to produce high-, mid-, and no-acid. X-ray photoelectron spectroscopy was used to analyze the chemical composition of the plasma polymer deposited layer. Limbal explants cultured on high acid-modified CLs outgrew more cells. Immunofluorescence and RT2-PCR array results indicated that a higher acrylic acid content can also help maintain progenitor cells during ex vivo expansion of epithelial cells. This study provides the first evidence for the ability of high acid-modified CLs to preserve the stemness and to be used as substrates for the culture of limbal cells in the treatment of LSCD.

  18. Enhanced biofouling resistance of polyethersulfone membrane surface modified with capsaicin derivative and itaconic acid

    International Nuclear Information System (INIS)

    Wang, Jian; Gao, Xueli; Wang, Qun; Sun, Haijing; Wang, Xiaojuan; Gao, Congjie

    2015-01-01

    Graphical abstract: - Highlights: • PES membrane was modified with a capsaicin derivative. • UV-assisted graft polymerization was carried out on membrane surface. • The capsaicin derivative modified membrane shows better antibiofouling property. - Abstract: The culprit of biofouling is the reproduction of viable microorganisms on the membrane surface. Recently, functionalization of membrane surface with natural antibacterial agents has drawn great attention. This work presents the fabrication of antibiofouling polyethersulfone (PES) ultrafiltration (UF) membranes by UV-assisted photo grafting of capsaicin derivative (N-(4-hydroxy-3-methoxy-benzyl)-acrylamide, HMBA) and itaconic acid (IA) on the surface of PES membrane. Results of FTIR-ATR, water static contact angle (WSCA) and atomic force microscopy (AFM) analysis confirmed the successful grafting of HMBA and IA on the membrane surface. We investigated the antifouling and antibacterial properties of these membranes using BSA and Escherichia coli as the test model, respectively. During a 150-min test, the modified membranes show much lower flux decline (42.7% for PES-g-1H0I, 22.2% for PES-g-1H1I and 7.7% for PES-g-1H5I) when compared with the pristine membrane (flux declined by 77%). The modified membranes exhibit excellent antibacterial activity (nearly 100%) when UV irradiation time was 6 min. The morphological study suggested that the E. coli on the pristine membrane showed a regular and smooth surface while that on the modified membrane was disrupted, which validated the antibacterial activity of the modified membranes.

  19. Enhanced biofouling resistance of polyethersulfone membrane surface modified with capsaicin derivative and itaconic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Gao, Xueli, E-mail: gxl_ouc@126.com [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Wang, Qun; Sun, Haijing; Wang, Xiaojuan [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Gao, Congjie, E-mail: gaocjie@ouc.edu.cn [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China)

    2015-11-30

    Graphical abstract: - Highlights: • PES membrane was modified with a capsaicin derivative. • UV-assisted graft polymerization was carried out on membrane surface. • The capsaicin derivative modified membrane shows better antibiofouling property. - Abstract: The culprit of biofouling is the reproduction of viable microorganisms on the membrane surface. Recently, functionalization of membrane surface with natural antibacterial agents has drawn great attention. This work presents the fabrication of antibiofouling polyethersulfone (PES) ultrafiltration (UF) membranes by UV-assisted photo grafting of capsaicin derivative (N-(4-hydroxy-3-methoxy-benzyl)-acrylamide, HMBA) and itaconic acid (IA) on the surface of PES membrane. Results of FTIR-ATR, water static contact angle (WSCA) and atomic force microscopy (AFM) analysis confirmed the successful grafting of HMBA and IA on the membrane surface. We investigated the antifouling and antibacterial properties of these membranes using BSA and Escherichia coli as the test model, respectively. During a 150-min test, the modified membranes show much lower flux decline (42.7% for PES-g-1H0I, 22.2% for PES-g-1H1I and 7.7% for PES-g-1H5I) when compared with the pristine membrane (flux declined by 77%). The modified membranes exhibit excellent antibacterial activity (nearly 100%) when UV irradiation time was 6 min. The morphological study suggested that the E. coli on the pristine membrane showed a regular and smooth surface while that on the modified membrane was disrupted, which validated the antibacterial activity of the modified membranes.

  20. Surface modification of poly(vinylidene fluoride) membrane with hydrophilic and anti-fouling performance via a two-step polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gui-E; Sun, Li; Huang, Hui-Hong; Liu, Yan-Jun [Shanghai Institute of Technology, Shanghai (China); Xu, Zhen-Liang; Yang, Hu [East China University of Science and Technology, Shanghai (China)

    2015-12-15

    The surface modification of poly (vinylidene fluoride) (PVDF) membrane was performed via a two-step polymerization reactions. Poly (acrylic acid) (PAAc) was first grafted onto the membrane surface for the preparation of PVDF-g-PAAc membrane, and then poly (ethylene glycol) 200 (PEG 200) was immobilized on the membrane surface by the esterification reaction for the fabrication of PVDF-g-PEGA membrane. Attenuated total reflectance (ATR) FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and protein adsorption, water flux, water content and dynamic contact angle were conducted to characterize the structures and performance of the resultant PVDF membranes. The experimental results showed that the adsorption of bovine serum albumin (BSA) on the PVDF-g-PEGA membrane decreased about 80% when the grafting ratio reached to 15 wt%, compared with the pristine PVDF membrane. Moreover, the water contact angle of the membrane dropped to 60.5o, while the membrane pore sizes remained little changed.

  1. Novel hydrophilic nanostructured microtexture on direct metal laser sintered Ti-6Al-4V surfaces enhances osteoblast response in vitro and osseointegration in a rabbit model.

    Science.gov (United States)

    Hyzy, Sharon L; Cheng, Alice; Cohen, David J; Yatzkaier, Gustavo; Whitehead, Alexander J; Clohessy, Ryan M; Gittens, Rolando A; Boyan, Barbara D; Schwartz, Zvi

    2016-08-01

    The purpose of this study was to compare the biological effects in vivo of hierarchical surface roughness on laser sintered titanium-aluminum-vanadium (Ti-6Al-4V) implants to those of conventionally machined implants on osteoblast response in vitro and osseointegration. Laser sintered disks were fabricated to have micro-/nano-roughness and wettability. Control disks were computer numerical control (CNC) milled and then polished to be smooth (CNC-M). Laser sintered disks were polished smooth (LST-M), grit blasted (LST-B), or blasted and acid etched (LST-BE). LST-BE implants or implants manufactured by CNC milling and grit blasted (CNC-B) were implanted in the femurs of male New Zealand white rabbits. Most osteoblast differentiation markers and local factors were enhanced on rough LST-B and LST-BE surfaces in comparison to smooth CNC-M or LST-M surfaces for MG63 and normal human osteoblast cells. To determine if LST-BE implants were osteogenic in vivo, we compared them to implant surfaces used clinically. LST-BE implants had a unique surface with combined micro-/nano-roughness and higher wettability than conventional CNC-B implants. Histomorphometric analysis demonstrated a significant improvement in cortical bone-implant contact of LST-BE implants compared to CNC-B implants after 3 and 6 weeks. However, mechanical testing revealed no differences between implant pullout forces at those time points. LST surfaces enhanced osteoblast differentiation and production of local factors in vitro and improved the osseointegration process in vivo. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2086-2098, 2016. © 2016 Wiley Periodicals, Inc.

  2. Electrochemical immobilization of biomolecules on gold surface modified with monolayered L-cysteine

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Mitsunori, E-mail: honda.mitsunori@jaea.go.jp; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie

    2014-04-01

    Immobilization of organic molecules on the top of a metal surface is not easy because of lattice mismatch between organic and metal crystals. Gold atoms bind to thiol groups through strong chemical bonds, and a self-assembled monolayer of sulfur-terminated organic molecules is formed on the gold surface. Herein, we suggested that a monolayer of L-cysteine deposited on a gold surface can act as a buffer layer to immobilize biomolecules on the metal surface. We selected lactic acid as the immobilized biomolecule because it is one of the simplest carboxyl-containing biomolecules. The immobilization of lactic acid on the metal surface was carried out by an electrochemical method in an aqueous environment under the potential range varying from − 0.6 to + 0.8 V. The surface chemical states before and after the electrochemical reaction were characterized using X-ray photoelectron spectroscopy (XPS). The N 1s and C 1s XPS spectra showed that the L-cysteine-modified gold surface can immobilize lactic acid via peptide bonds. This technique might enable the immobilization of large organic molecules and biomolecules. - Highlights: • Monolayer l-cysteine deposited on Au surface as a buffer layer to immobilize biomolecules. • Lactic acid as the immobilized biomolecule as it is simple carboxyl-containing biomolecule. • X-ray photoelectron spectroscopy (XPS) of surface chemical states, before and after. • L-cysteine-modified Au surface can immobilize lactic acid via peptide bonds.

  3. Electrochemical immobilization of biomolecules on gold surface modified with monolayered L-cysteine

    International Nuclear Information System (INIS)

    Honda, Mitsunori; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie

    2014-01-01

    Immobilization of organic molecules on the top of a metal surface is not easy because of lattice mismatch between organic and metal crystals. Gold atoms bind to thiol groups through strong chemical bonds, and a self-assembled monolayer of sulfur-terminated organic molecules is formed on the gold surface. Herein, we suggested that a monolayer of L-cysteine deposited on a gold surface can act as a buffer layer to immobilize biomolecules on the metal surface. We selected lactic acid as the immobilized biomolecule because it is one of the simplest carboxyl-containing biomolecules. The immobilization of lactic acid on the metal surface was carried out by an electrochemical method in an aqueous environment under the potential range varying from − 0.6 to + 0.8 V. The surface chemical states before and after the electrochemical reaction were characterized using X-ray photoelectron spectroscopy (XPS). The N 1s and C 1s XPS spectra showed that the L-cysteine-modified gold surface can immobilize lactic acid via peptide bonds. This technique might enable the immobilization of large organic molecules and biomolecules. - Highlights: • Monolayer l-cysteine deposited on Au surface as a buffer layer to immobilize biomolecules. • Lactic acid as the immobilized biomolecule as it is simple carboxyl-containing biomolecule. • X-ray photoelectron spectroscopy (XPS) of surface chemical states, before and after. • L-cysteine-modified Au surface can immobilize lactic acid via peptide bonds

  4. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Torres, David [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Huerta, Francisco [Departamento de Ingenieria Textil y Papelera, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell, 1. E-03801 Alcoy (Spain); Montilla, Francisco, E-mail: francisco.montilla@ua.e [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Morallon, Emilia [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain)

    2011-02-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong {pi}-{pi} interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  5. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    International Nuclear Information System (INIS)

    Salinas-Torres, David; Huerta, Francisco; Montilla, Francisco; Morallon, Emilia

    2011-01-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong π-π interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  6. An investigation of phase transformation and crystallinity in laser surface modified H13 steel

    Science.gov (United States)

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

    2013-03-01

    This paper presents a laser surface modification process of AISI H13 tool steel using 0.09, 0.2 and 0.4 mm size of laser spot with an aim to increase hardness properties. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). X-ray diffraction analysis (XRD) was conducted to measure crystallinity of the laser-modified surface. X-ray diffraction patterns of the samples were recorded using a Bruker D8 XRD system with Cu K α ( λ=1.5405 Å) radiation. The diffraction patterns were recorded in the 2 θ range of 20 to 80°. The hardness properties were tested at 981 mN force. The laser-modified surface exhibited reduced crystallinity compared to the un-processed samples. The presence of martensitic phase was detected in the samples processed using 0.4 mm spot size. Though there was reduced crystallinity, a high hardness was measured in the laser-modified surface. Hardness was increased more than 2.5 times compared to the as-received samples. These findings reveal the phase source of the hardening mechanism and grain composition in the laser-modified surface.

  7. Enhanced osteoblast responses to poly ether ether ketone surface modified by water plasma immersion ion implantation.

    Science.gov (United States)

    Wang, Heying; Lu, Tao; Meng, Fanhao; Zhu, Hongqin; Liu, Xuanyong

    2014-05-01

    Poly ether ether ketone (PEEK) offers a set of characteristics superior for human implants; however, its application is limited by the bio-inert surface property. In this work, PEEK surface was modified using single step plasma immersion ion implantation (PIII) treatment with a gas mixture of water vapor as a plasma resource and argon as an ionization assistant. Field emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy were used to investigate the microstructure and composition of the modified PEEK surface. The water contact angle and zeta-potential of the surfaces were also measured. Osteoblast precursor cells MC3T3-E1 and rat bone mesenchymal stem cells were cultured on the PEEK samples to evaluate their cytocompatibility. The obtained results show that the hydroxyl groups as well as a "ravined structure" are constructed on water PIII modified PEEK. Compared with pristine PEEK, the water PIII treated PEEK is more favorable for osteoblast adhesion, spreading and proliferation, besides, early osteogenic differentiation indicated by the alkaline phosphatase activity is also up-regulated. Our study illustrates enhanced osteoblast responses to the PEEK surface modified by water PIII, which gives positive information in terms of future biomedical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    OpenAIRE

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    1999-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface mo...

  9. Application of a modified electrochemical system for surface decontamination of radioactive metal waste

    International Nuclear Information System (INIS)

    Lee, J.H.; Lim, Y.K.; Yang, H.Y.; Shin, S.W.; Song, M.J.

    2003-01-01

    Conventional and modified electrolytic decontamination experiments were performed in a solution of sodium sulfate for the decontamination of carbon steel as the simulated metal wastes which are generated in large amounts from nuclear power plants. The effect of reaction time, current density and concentration of electrolytes in the modified electrolytic decontamination system were examined to remove the surface contamination of the simulated radioactive metal wastes. As for the results of this research, the modified electrochemical decontamination process can decontaminate more effectively than the conventional decontamination process by applying different anode material which causes higher induced electro-motive forces. When 0.5 M sodium sulfate, 0.4 A/cm 2 current density and 30 minutes reaction time were applied in the modified process, a 16 μm thickness change that is expected to remove most surface contamination in radioactive metal wastes was achieved on carbon steel which is the main material of radioactive metal waste in nuclear power plants. The decontamination efficiency of metal waste showed similar results with the small and large lab-scale modified electrochemical system. The application of this modified electrolytic decontamination system is expected to play a considerable role for decontamination of radioactive metal waste in nuclear power plants in the near future. (author)

  10. Comparative of fibroblast and osteoblast cells adhesion on surface modified nanofibrous substrates based on polycaprolactone

    OpenAIRE

    Sharifi, Fereshteh; Irani, Shiva; Zandi, Mojgan; Soleimani, Masoud; Atyabi, Seyed Mohammad

    2016-01-01

    One of the determinant factors for successful bioengineering is to achieve appropriate nano-topography and three-dimensional substrate. In this research, polycaprolactone (PCL) nano-fibrous mat with different roughness modified with O2 plasma was fabricated via electrospinning. The purpose of this study was to evaluate the effect of plasma modification along with surface nano-topography of mats on the quality of human fibroblast (HDFs) and osteoblast cells (OSTs)-substrate interaction. Surfac...

  11. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces.

    Science.gov (United States)

    Jogikalmath, G; Stuart, J K; Pungor, A; Hlady, V

    1999-08-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si(3)N(4) tip surfaces was found for all modified glass surfaces.

  12. Existence of a tribo-modified surface layer of BR/S-SBR elastomers reinforced with silica or carbon black

    NARCIS (Netherlands)

    Mokhtari, Milad; Schipper, Dirk J.

    2016-01-01

    The existence of a modified surface layer on top of a rubber disk, in contact with a rigid counter-surface, is still a point of discussion. In this study, we show that a modified surface layer with different mechanical properties exists. Modification of the reinforced elastomers is discussed and the

  13. Electrochemical and morphological analyses on the titanium surface modified by shot blasting and anodic oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Szesz, Eduardo M., E-mail: eszesz@neoortho.com.br [Neoortho Research Institute, Rua Ângelo Domingos Durigan, 607-Cascatinha, CEP 82025-100 Curitiba, PR (Brazil); Pereira, Bruno L., E-mail: brnl7@hotmail.com [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Kuromoto, Neide K., E-mail: kuromoto@fisica.ufpr.br [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Marino, Claudia E.B., E-mail: claudiamarino@yahoo.com [Mechanical Engineering Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Souza, Gelson B. de, E-mail: gelsonbs@uepg.br [Physics Department, Universidade Estadual de Ponta Grossa, 84051-510 Ponta Grossa, PR (Brazil); Soares, Paulo, E-mail: pa.soares@pucpr.br [Mechanical Engineering Department, Pontifícia Universidade Católica do Paraná, 80215-901 Curitiba, PR (Brazil)

    2013-01-01

    In recent years, many surface modification processes have been developed in order to induce the osseointegration on titanium surface and thus to improve the implants' biocompatibility. In this work, Ti surface has been modified by shot blasting followed by anodic oxidation process in order to associate the good surface characteristics of both processes to obtain a rough and porous surface able to promote the titanium surface bioactivity. Commercially pure titanium (grade 2) plates were used on the surface treatments that were as follows: Shot blasting (SB) performed using alumina (Al{sub 2}O{sub 3}) particles, and anodic oxidation (AO) using NaOH electrolyte. The morphology, structural changes and the open-circuit potentials (OCP) of the surfaces were analyzed. It can be observed that an increase on the roughness of the blasted surface and a rough and porous surface happens after the AO process. The anodic film produced is thin and followed the blasted surface topography. It can be observed that there are small pores with regular shape covering the entire surface. X-ray diffraction results showed the presence of the anatase and rutile phases on the blasted and anodized surface after heat treatment at 600 °C/1 h. Concerning electrochemical measurements, when the different samples were submitted to open-circuit conditions in a physiological electrolyte, the protective effect increases with the oxidation process due to the oxide layer. When the surface was blasted, the OCP was more negative when compared with the Ti surface without surface treatments. - Highlights: ► A combination of shot blasting and anodic oxidation surface treatments is proposed. ► Both processes produced an increase in roughness compared to the polished surface. ► The combination of processes produced a rough and porous surface. ► Open circuit results show that the protective effect increases with oxidation process. ► The combination of processes presents the better results in this

  14. Optimization of Phospholipase A1 Immobilization on Plasma Surface Modified Chitosan Nanofibrous Mat

    Directory of Open Access Journals (Sweden)

    Zahra Beig Mohammadi

    2016-01-01

    Full Text Available Phospholipase A1 is known as an effective catalyst for hydrolysis of various phospholipids in enzymatic vegetable oil degumming. Immobilization is one of the most efficient strategies to improve its activity, recovery and functional properties. In this study, chitosan-co-polyethylene oxide (90:10 nanofibrous mat was successfully fabricated and modified with atmospheric plasma at different times (2, 6 and 10 min to interact with enzyme molecules. Scanning electron microscopy images revealed that the membranes retained uniform nanofibrous and open porous structures before and after the treatment. PLA1 was successfully immobilized onto the membrane surfaces via covalent bonds with the functional groups of chitosan nanofibrous mat. Response surface methodology was used to optimize the immobilization conditions for reaching the maximum immobilization efficiency. Enzyme concentration, pH, and immobilization time were found to be significant key factors. Under optimum conditions (5.03 h, pH 5.63, and enzyme dosage 654.36 UI, the atmospheric plasma surface modified chitosan nanofibers reached the highest immobilization efficiency (78.50%. Fourier transform infrared spectroscopy of the control and plasma surface-modified chitosan nanofibers revealed the functional groups of nanofibers and their reaction with the enzyme. The results indicated that surface modification by atmospheric plasma induced an increase in PLA1 loading on the membrane surfaces.

  15. Enhanced photoelectrochemical and photocatalytic activity of WO3-surface modified TiO2 thin film

    Science.gov (United States)

    Qamar, Mohammad; Drmosh, Qasem; Ahmed, Muhammad I.; Qamaruddin, Muhammad; Yamani, Zain H.

    2015-02-01

    Development of nanostructured photocatalysts for harnessing solar energy in energy-efficient and environmentally benign way remains an important area of research. Pure and WO3-surface modified thin films of TiO2 were prepared by magnetron sputtering on indium tin oxide glass, and photoelectrochemical and photocatalytic activities of these films were studied. TiO2 particles were <50 nm, while deposited WO3 particles were <20 nm in size. An enhancement in the photocurrent was observed when the TiO2 surface was modified WO3 nanoparticles. Effect of potential, WO3 amount, and radiations of different wavelengths on the photoelectrochemical activity of TiO2 electrodes was investigated. Photocatalytic activity of TiO2 and WO3-modified TiO2 for the decolorization of methyl orange was tested.

  16. Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins.

    Science.gov (United States)

    Forato, Florian; Liu, Hao; Benoit, Roland; Fayon, Franck; Charlier, Cathy; Fateh, Amina; Defontaine, Alain; Tellier, Charles; Talham, Daniel R; Queffélec, Clémence; Bujoli, Bruno

    2016-06-07

    Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr(4+), afforded better immobilization of the peptides and proteins and efficient capture of their targets.

  17. Microgel-based surface modifying system for stimuli-responsive functional finishing of cotton

    NARCIS (Netherlands)

    Kulkarni, A.N.; Tourrette, A.; Warmoeskerken, Marinus; Jocic, D.

    2010-01-01

    An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as

  18. Investigation of Streptococcus mutans biofilm growth on modified Au(111)-surfaces using AFM and electrochemistry

    DEFF Research Database (Denmark)

    Hu, Yifan; Zhang, Jingdong; Ulstrup, Jens

    2011-01-01

    Biofilms of the bacterium Streptococcus mutans constitute perhaps the most important direct cause of human dental caries formation. We have studied S. mutans biofilm formation and properties on Au(111)-surfaces modified by self-assembled molecular monolayers (SAMs) of different thiol-based molecu...

  19. Modified-surface-energy methods for deriving heavy-ion potentials

    International Nuclear Information System (INIS)

    Sierk, A.J.

    1977-01-01

    The use of a modified-surface-energy approach for the calculation of heavy-ion interaction potentials is discussed. It is not possible to simultaneously fit elastic scattering, ion interaction barriers, and fission barriers with the same set of constants in this model. Possible explanations of this deficiency are discussed

  20. Surface characterization of weathered wood-plastic composites produced from modified wood flour

    Science.gov (United States)

    James S. Fabiyi; Armando G. McDonald; Nicole M. Stark

    2007-01-01

    The effects of weathering on the surface properties of wood-plastic composites (WPC) were examined. High-density polyethylene (HDPE) based WPCs made from modified wood flour (untreated, extractives free, and holocellulose (delignified) fibers) were subjected to accelerated (xenon-arc) weathering. Colorimetry and Fourier-transform infrared spectroscopy were employed to...

  1. Mirror-finished superhydrophobic aluminum surfaces modified by anodic alumina nanofibers and self-assembled monolayers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2018-05-01

    We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

  2. Boiling performance and material robustness of modified surfaces with multi scale structures for fuel cladding development

    Energy Technology Data Exchange (ETDEWEB)

    Jo, HangJin; Kim, Jin Man [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Yeom, Hwasung [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States); Lee, Gi Cheol [Department of Mechanical Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Kiyofumi, Moriyama; Kim, Moo Hwan [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784, Gyungbuk (Korea, Republic of); Sridharan, Kumar; Corradini, Michael [Department of Nuclear Engineering and Engineering physics, UW-Madison, Madison, WI 53706, Unities States (United States)

    2015-09-15

    Highlights: • We improved boiling performance and material robustness using surface modification. • We combined micro/millimeter post structures and nanoparticles with heat treatments. • Compactly-arranged micrometer posts had improved boiling performance. • CHF increased significantly due to capillary pumping by the deposited NP layers. • Sintering procedure increased mechanical strength of the NP coating surface. - Abstract: By regulating the geometrical characteristics of multi-scale structures and by adopting heat treatment for protective layer of nanoparticles (NPs), we improved critical heat flux (CHF), boiling heat transfer (BHT), and mechanical robustness of the modified surface. We fabricated 1-mm and 100-μm post structures and deposited NPs on the structured surface as a nano-scale structured layer and protective layer at the same time, then evaluated the CHF and BHT and material robustness of the modified surfaces. On the structured surfaces without NPs, the surface with compactly-arranged micrometer posts had improved CHF (118%) and BHT (41%). On the surface with structures on which NPs had been deposited, CHF increased significantly (172%) due to capillary pumping by the deposited NP layers. The heat treatment improved robustness of coating layer in comparison to the one of before heat treatment. In particular, low-temperature sintering increased the hardness of the modified surface by 140%. The increased mechanical strength of the NP coating is attributed to reduction in coating porosity during sintering. The combination of micrometer posts structures and sintered NP coating can increase the safety, efficiency and reliability of advanced nuclear fuel cladding.

  3. Boiling performance and material robustness of modified surfaces with multi scale structures for fuel cladding development

    International Nuclear Information System (INIS)

    Jo, HangJin; Kim, Jin Man; Yeom, Hwasung; Lee, Gi Cheol; Park, Hyun Sun; Kiyofumi, Moriyama; Kim, Moo Hwan; Sridharan, Kumar; Corradini, Michael

    2015-01-01

    Highlights: • We improved boiling performance and material robustness using surface modification. • We combined micro/millimeter post structures and nanoparticles with heat treatments. • Compactly-arranged micrometer posts had improved boiling performance. • CHF increased significantly due to capillary pumping by the deposited NP layers. • Sintering procedure increased mechanical strength of the NP coating surface. - Abstract: By regulating the geometrical characteristics of multi-scale structures and by adopting heat treatment for protective layer of nanoparticles (NPs), we improved critical heat flux (CHF), boiling heat transfer (BHT), and mechanical robustness of the modified surface. We fabricated 1-mm and 100-μm post structures and deposited NPs on the structured surface as a nano-scale structured layer and protective layer at the same time, then evaluated the CHF and BHT and material robustness of the modified surfaces. On the structured surfaces without NPs, the surface with compactly-arranged micrometer posts had improved CHF (118%) and BHT (41%). On the surface with structures on which NPs had been deposited, CHF increased significantly (172%) due to capillary pumping by the deposited NP layers. The heat treatment improved robustness of coating layer in comparison to the one of before heat treatment. In particular, low-temperature sintering increased the hardness of the modified surface by 140%. The increased mechanical strength of the NP coating is attributed to reduction in coating porosity during sintering. The combination of micrometer posts structures and sintered NP coating can increase the safety, efficiency and reliability of advanced nuclear fuel cladding

  4. Surface-modified silk hydrogel containing hydroxyapatite nanoparticle with hyaluronic acid-dopamine conjugate.

    Science.gov (United States)

    Kim, Hyung Hwan; Park, Jong Bo; Kang, Min Ji; Park, Young Hwan

    2014-09-01

    Silk fibroin/hydroxyapatite (SF/HAp) composite hydrogels were fabricated in this study, having different HAp contents (0-33 wt%) in SF matrix hydrogel. Surface modification of HAp nanoparticle with hyaluronic acid (HA)-dopamine (DA) conjugate improved a dispersibility of HAp in aqueous SF solution due to its negatively charged surface and therefore, fabrication of the SF composite hydrogel having HAp nanoparticles inside could be possible. Zeta potential of surface-modified HAP was examined by ELS. It demonstrates that surface of HAp was well modified to a negative charge with HA-DA. Morphological structure of SF hydrogel containing surface-modified HAp was examined by FE-SEM for analyzing pore structure of hydrogel and deposition of HAp nanoparticle in SF hydrogel. It was found that HAp nanoparticles were uniformly deposited on the pore wall of SF hydrogel. Structural characteristics of SF/HAp composite hydrogel was performed using X-ray diffraction and FT-IR analysis. It was found that β-sheet crystal conformation of SF was significantly influenced by the HAp content during gelation of a mixture of SF and HAp. As a result of MTT assay, the SF/HAp composite hydrogel showed excellent cell proliferation ability. Therefore, it is expected that SF hydrogel containing HAp nanoparticles has a high potential as bone regeneration scaffold. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Self-Patterning of Silica/Epoxy Nanocomposite Underfill by Tailored Hydrophilic-Superhydrophobic Surfaces for 3D Integrated Circuit (IC) Stacking.

    Science.gov (United States)

    Tuan, Chia-Chi; James, Nathan Pataki; Lin, Ziyin; Chen, Yun; Liu, Yan; Moon, Kyoung-Sik; Li, Zhuo; Wong, C P

    2017-03-15

    As microelectronics are trending toward smaller packages and integrated circuit (IC) stacks nowadays, underfill, the polymer composite filled in between the IC chip and the substrate, becomes increasingly important for interconnection reliability. However, traditional underfills cannot meet the requirements for low-profile and fine pitch in high density IC stacking packages. Post-applied underfills have difficulties in flowing into the small gaps between the chip and the substrate, while pre-applied underfills face filler entrapment at bond pads. In this report, we present a self-patterning underfilling technology that uses selective wetting of underfill on Cu bond pads and Si 3 N 4 passivation via surface energy engineering. This novel process, fully compatible with the conventional underfilling process, eliminates the issue of filler entrapment in typical pre-applied underfilling process, enabling high density and fine pitch IC die bonding.

  6. Numerical simulation of binary collisions using a modified surface tension model with particle method

    International Nuclear Information System (INIS)

    Sun Zhongguo; Xi Guang; Chen Xi

    2009-01-01

    The binary collision of liquid droplets is of both practical importance and fundamental value in computational fluid mechanics. We present a modified surface tension model within the moving particle semi-implicit (MPS) method, and carry out two-dimensional simulations to investigate the mechanisms of coalescence and separation of the droplets during binary collision. The modified surface tension model improves accuracy and convergence. A mechanism map is established for various possible deformation pathways encountered during binary collision, as the impact speed is varied; a new pathway is reported when the collision speed is critical. In addition, eccentric collisions are simulated and the effect of the rotation of coalesced particle is explored. The results qualitatively agree with experiments and the numerical protocol may find applications in studying free surface flows and interface deformation

  7. Surface analysis of gold nanoparticles functionalized with thiol-modified glucose SAMs for biosensor applications.

    Directory of Open Access Journals (Sweden)

    Valentina eSpampinato

    2016-02-01

    Full Text Available In this work, Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS, Principal Component Analysis (PCA and X-ray Photoelectron Spectroscopy (XPS have been used to characterize the surface chemistry of gold substrates before and after functionalization with thiol-modified glucose self-assembled monolayers and subsequent biochemical specific recognition of maltose binding protein (MBP.The results indicate that the surface functionalization is achieved both on flat and nanoparticles gold substrates thus showing the potential of the developed system as biodetection platform. Moreover, the method presented here has been found to be a sound and valid approach to characterize the surface chemistry of nanoparticles functionalized with large molecules.Both techniques were proved to be very useful tools for monitoring all the functionalization steps, including the investigation of the biological behaviour of the glucose-modified particles in presence of the maltose binding protein.

  8. Poly thiophene hydrophobic and hydrophilic compounds, silver and iodine synthesized by plasma; Compuestos hidrofobicos e hidrofilicos de politiofeno, plata y yodo sintetizados por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, J.C.; Chavez, J.A. [IIM, UNAM, Circuito exterior, Ciudad Universitaria, 04510 Coyoacan, D.F. (Mexico); Olayo, M.G.; Cruz, G.J. [ININ, Apdo. Postal 18-1027, 11801 Mexico D.F. (Mexico)

    2007-07-01

    Compounds in thin films of poly thiophene with silver and poly thiophene doped with iodine and silver using splendor discharges were synthesized. It is studied the wettability of the compounds and its transport properties. It was found that the compounds can modify their hydrophilic to hydrophobic behavior controlling their surface ruggedness and the metallic content. The doped with iodine plays a fundamental paper in the modification of the ruggedness of the compounds. (Author)

  9. Osseointegration improvement by plasma electrolytic oxidation of modified titanium alloys surfaces.

    Science.gov (United States)

    Echeverry-Rendón, Mónica; Galvis, Oscar; Quintero Giraldo, David; Pavón, Juan; López-Lacomba, José Luis; Jiménez-Piqué, Emilio; Anglada, Marc; Robledo, Sara M; Castaño, Juan G; Echeverría, Félix

    2015-02-01

    Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.

  10. Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

    Energy Technology Data Exchange (ETDEWEB)

    Gasik, Michael, E-mail: michael.gasik@aalto.fi [Aalto University Foundation, School of Chemical Technology, P.O. Box 16200, FIN-00076 AALTO (Finland); Braem, Annabel [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Chaudhari, Amol; Duyck, Joke [Department of Prosthetic Dentistry, BIOMAT Research Cluster, KU Leuven, Kapucijnenvoer 7a, B-3000 Leuven (Belgium); Vleugels, Jozef [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium)

    2015-04-01

    Titanium-based implants are widely used in modern clinical practice, but their “optimal” properties in terms of porosity and topology, roughness and hydrophilic parameters are being a subject of intensive discussions. Recent in vitro results have shown a possibility to optimize the surface of an implant with maximal repelling of bacteria (Staphylococcus aureus, Staphylococcus epidermidis) and improvement in human osteogenic and endothelial cell adhesion, proliferation and differentiation. In this work, these different grades titanium implants were tested in vivo using the same analytical methodology. In addition to material parameters, key histomorphometrical parameters such a regeneration area, bone adaptation area and bone-to-implant contact were determined after 2 and 4 weeks of implantation in rabbit animal model. Porous implants have more clear differences than non-porous ones, with the best optimum values obtained on hydrothermally treated electrophoretically deposited titanium. These in vivo data correlate well with the optimal prediction made by in vitro tests. - Highlights: • Various titanium specimens were studied in vivo on osteointegration vs their properties. • Non-porous implants had a better performance when coated with bioactive glass. • Porous implants have shown the best results for hydrothermally treated specimens. • Good correlation was found with the previous in vitro tests. • New analysis of the in vivo data has shown benefits to assess biomaterials performance.

  11. Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

    International Nuclear Information System (INIS)

    Torres, Cecilia C.; Urbano, Bruno F.; Campos, Cristian H.; Rivas, Bernabé L.; Reyes, Patricio

    2015-01-01

    This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, 29 Si and 13 C solid state NMR, and N 2 adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point

  12. Composite hydrogel based on surface modified mesoporous silica and poly[(2-acryloyloxy)ethyl trimethylammonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Cecilia C. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Urbano, Bruno F., E-mail: burbano@udec.cl [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Campos, Cristian H. [Department of Organic Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Rivas, Bernabé L. [Department of Polymer Chemistry, Faculty of Chemical Science, University of Concepción (Chile); Reyes, Patricio [Department of Physical Chemistry, Faculty of Chemical Science, University of Concepción (Chile)

    2015-02-15

    This work focused on the synthesis, characterization and water absorbency of a composite hydrogel based on poly[(2-acryloyloxy)ethyl trimethylammonium chloride] and mesoporous silica, MCM-41. The MCM-41 was synthesized and later surface functionalized with triethoxyvinylsilane (VTES) and 3-trimethoxysilylpropylmethacrylate (TMSPM) by a post-grafting procedure. The composite hydrogels were obtained by in-situ polymerization using a mixture of monomer, crosslinker and initiator in the presence of functionalized MCM-41. Diverse characterization techniques were used at the different stages of synthesis, namely, FT-IR, TEM, SEM, DRX, {sup 29}Si and {sup 13}C solid state NMR, and N{sub 2} adsorption isotherms at 77 K. Finally, the water uptake performance of the composites was tested as a function of time, mesoporous silica loading and coupling agent used at the functionalization. The composites using non-functionalized MCM-41 reached the highest water uptake, whereas those composite with MCM-41 TMSPM exhibited the lowest sorption. - Highlights: • Hydrophilic crosslinked polymer-mesoporous silica was obtained. • Mesoporous silica MCM-41 was synthesized and functionalized with organosilane. • Functionalization of MCM-41 affects the water uptake of composite. • Mesoporous silica is covalently bound to the polymer acting as crosslinked point.

  13. Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

    International Nuclear Information System (INIS)

    Gasik, Michael; Braem, Annabel; Chaudhari, Amol; Duyck, Joke; Vleugels, Jozef

    2015-01-01

    Titanium-based implants are widely used in modern clinical practice, but their “optimal” properties in terms of porosity and topology, roughness and hydrophilic parameters are being a subject of intensive discussions. Recent in vitro results have shown a possibility to optimize the surface of an implant with maximal repelling of bacteria (Staphylococcus aureus, Staphylococcus epidermidis) and improvement in human osteogenic and endothelial cell adhesion, proliferation and differentiation. In this work, these different grades titanium implants were tested in vivo using the same analytical methodology. In addition to material parameters, key histomorphometrical parameters such a regeneration area, bone adaptation area and bone-to-implant contact were determined after 2 and 4 weeks of implantation in rabbit animal model. Porous implants have more clear differences than non-porous ones, with the best optimum values obtained on hydrothermally treated electrophoretically deposited titanium. These in vivo data correlate well with the optimal prediction made by in vitro tests. - Highlights: • Various titanium specimens were studied in vivo on osteointegration vs their properties. • Non-porous implants had a better performance when coated with bioactive glass. • Porous implants have shown the best results for hydrothermally treated specimens. • Good correlation was found with the previous in vitro tests. • New analysis of the in vivo data has shown benefits to assess biomaterials performance

  14. Glucose oxidase immobilization on different modified surfaces of platinum nanowire for application in glucose detection

    International Nuclear Information System (INIS)

    Le, Thi Thanh Tuyen; Tran, Phu Duy; Pham, Xuan Tung; Tong, Duy Hien; Dang, Mau Chien

    2010-01-01

    In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO 2 , polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained about 60% of its initial value after it was stored at 4 °C in a 100 mM PBS buffer solution with a pH of 7.2 for a period of 30 days

  15. Surface-modified Y zeolite-filled chitosan membrane for direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hong; Zheng, Bin; Zheng, Xiaohong; Wang, Jingtao; Yuan, Weikang; Jiang, Zhongyi [Key Laboratory for Green Chemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2007-11-15

    Hybrid membranes composed of chitosan (CS) as organic matrix and surface-modified Y zeolite as inorganic filler are prepared and their applicability for DMFC is demonstrated by methanol permeability, proton conductivity and swelling property. Y zeolite is modified using silane coupling agents, 3-aminopropyl-triethoxysilane (APTES) and 3-mercaptopropyl-trimethoxysilane (MPTMS), to improve the organic-inorganic interfacial morphology. The mercapto group on MPTMS-modified Y zeolite is further oxidized into sulfonic group. Then, the resultant surface-modified Y zeolites with either aminopropyl groups or sulfonicpropyl groups are mixed with chitosan in acetic acid solution and cast into membranes. The transitional phase generated between chitosan matrix and zeolite filler reduces or even eliminates the nonselective voids commonly exist at the interface. The hybrid membranes exhibit a significant reduction in methanol permeability compared with pure chitosan and Nafion117 membranes, and this reduction extent becomes more pronounced with the increase of methanol concentration. By introducing -SO{sub 3}H groups onto zeolite surface, the conductivity of hybrid membranes is increased up to 2.58 x 10{sup -2} S cm{sup -1}. In terms of the overall selectivity index ({beta} = {sigma}/P), the hybrid membrane is comparable with Nafion117 at low methanol concentration (2 mol L{sup -1}) and much better (three times) at high methanol concentration (12 mol L{sup -1}). (author)

  16. Glucose oxidase immobilization on different modified surfaces of platinum nanowire for application in glucose detection

    Science.gov (United States)

    Thanh Tuyen Le, Thi; Duy Tran, Phu; Pham, Xuan Tung; Hien Tong, Duy; Chien Dang, Mau

    2010-09-01

    In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO2, polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained about 60% of its initial value after it was stored at 4 °C in a 100 mM PBS buffer solution with a pH of 7.2 for a period of 30 days.

  17. Phonon dispersion on Ag (100) surface: A modified analytic embedded atom method study

    International Nuclear Information System (INIS)

    Zhang Xiao-Jun; Chen Chang-Le

    2016-01-01

    Within the harmonic approximation, the analytic expression of the dynamical matrix is derived based on the modified analytic embedded atom method (MAEAM) and the dynamics theory of surface lattice. The surface phonon dispersions along three major symmetry directions, and XM-bar are calculated for the clean Ag (100) surface by using our derived formulas. We then discuss the polarization and localization of surface modes at points X-bar and M-bar by plotting the squared polarization vectors as a function of the layer index. The phonon frequencies of the surface modes calculated by MAEAM are compared with the available experimental and other theoretical data. It is found that the present results are generally in agreement with the referenced experimental or theoretical results, with a maximum deviation of 10.4%. The agreement shows that the modified analytic embedded atom method is a reasonable many-body potential model to quickly describe the surface lattice vibration. It also lays a significant foundation for studying the surface lattice vibration in other metals. (paper)

  18. X-ray photoelectron spectroscopy of rice husk surface modified with maleated polypropylene and silane

    International Nuclear Information System (INIS)

    Park, B.-D.; Wi, Seung Gon; Lee, Kwang Ho; Singh, A.P.; Yoon, Tae-Ho; Kim, Y.S.

    2004-01-01

    Rice husks were subjected to dry-grinding and steam-explosion to reduce their sizes. Subsequently, the surface of rice husk particles was modified using two different coupling agents, maleated polypropylene (MAPP) and γ-aminopropyltriethoxysilane (γ-APS, A-1100) to induce chemical reactions between the husk surface and the coupling agents used. The modified surface properties of rice husk were examined using X-ray photoelectron spectroscopy and FT-IR spectroscopy. Dry grinding, a simple method of fracturing husk, provided particulate segments, while steam explosion separated husk into fibrous components. When treated with MAPP, the O/C ratio of the husk surface decreased for both dry ground and steam-exploded husk. The γ-APS treatment resulted in an increase in the Si/O ratio for dry ground husk surface while this ratio decreased for steam-exploded husk particles. These results indicated that both coupling agents might be linked to the husk surface through chemical reactions. FT-IR results also supported the occurrence of ester and ether bonds after treatment of husks with MAPP and γ-APS. The present work suggested that the method of preparing rice husk particles had a great impact on their surface properties, and would therefore affect the interfacial adhesion in rice husk-thermoplastic composites

  19. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kanjanakawinkul, Watchara [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Rades, Thomas [School of Pharmacy, University of Otago, Dunedin 9054 (New Zealand); Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark); Puttipipatkhachorn, Satit [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand); Pongjanyakul, Thaned, E-mail: thaned@kku.ac.th [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2013-04-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties.

  20. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    International Nuclear Information System (INIS)

    Kanjanakawinkul, Watchara; Rades, Thomas; Puttipipatkhachorn, Satit; Pongjanyakul, Thaned

    2013-01-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties

  1. Functionalization of a Hydrophilic Commercial Membrane Using Inorganic-Organic Polymers Coatings for Membrane Distillation

    Directory of Open Access Journals (Sweden)

    Lies Eykens

    2017-06-01

    Full Text Available Membrane distillation is a thermal separation technique using a microporous hydrophobic membrane. One of the concerns with respect to the industrialization of the technique is the development of novel membranes. In this paper, a commercially available hydrophilic polyethersulfone membrane with a suitable structure for membrane distillation was modified using available hydrophobic coatings using ORMOCER® technology to obtain a hydrophobic membrane that can be applied in membrane distillation. The surface modification was performed using a selection of different components, concentrations, and application methods. The resulting membranes can have two hydrophobic surfaces or a hydrophobic and hydrophilic surface depending on the application method. An extensive characterization procedure confirmed the suitability of the coating technique and the obtained membranes for membrane distillation. The surface contact angle of water could be increased from 27° up to 110°, and fluxes comparable to membranes commonly used for membrane distillation were achieved under similar process conditions. A 100 h test demonstrated the stability of the coating and the importance of using sufficiently stable base membranes.

  2. Preparation and Evaluation of Dexamethasone (DEX/Growth and Differentiation Factor-5 (GDF-5 Surface-Modified Titanium Using β-Cyclodextrin-Conjugated Heparin (CD-Hep for Enhanced Osteogenic Activity In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Dae Hyeok Yang

    2017-08-01

    Full Text Available The most ideal implant models in the dental and orthopedic fields to minimize the failure rate of implantation involve the improvement of osseointegration with host bone. Therefore, a focus of this study is the preparation of surface-modified titanium (Ti samples of disc and screw types using dexamethasone (DEX and/or growth and differentiation factor-5 (GDF-5, as well as the evaluation of their efficacies on bone formation in vitro and in vivo. X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM and contact angle measurement were used to evaluate the surface chemical composition, surface morphology and wettability, respectively. The results showed that implant surfaces were successfully modified with DEX and/or GDF-5, and had rough surfaces along with hydrophilicity. DEX, GDF-5 or DEX/GDF-5 on the surface-modified samples were rapidly released within one day and released for 28 days in a sustained manner. The proliferation and bone formation of MC3T3-E1 cells cultured on pristine and surface-modified implants in vitro were examined by cell counting kit-8 (CCK-8 assay, as well as the measurements of alkaline phosphatase (ALP activity and calcium deposition, respectively. MC3T3-E1 cells cultured on DEX/GDF-5–Ti showed noticeable ALP activity and calcium deposition in vitro. Active bone formation and strong osseointegration occurred at the interface between DEX/GDF-5–Ti and host bone, as evaluated by micro computed-tomography (micro CT analysis. Surface modification using DEX/GDF-5 could be a good method for advanced implants for orthopaedic and dental applications.

  3. Hydrophilic-Core Microcapsules and Their Formation

    Science.gov (United States)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor)

    2016-01-01

    Hydrophilic-core microcapsules and methods of their formation are provided. A hydrophilic-core microcapsule may include a shell that encapsulates water with the core substance dissolved or dispersed therein. The hydrophilic-core microcapsules may be formed from an emulsion having hydrophilic-phase droplets dispersed in a hydrophobic phase, with shell-forming compound contained in the hydrophilic phase or the hydrophobic phase and the core substance contained in the hydrophilic phase. The shells of the microcapsules may be capable of being broken down in response to being contacted by an alkali, e.g., produced during corrosion, contacting the shell.

  4. Surface characterization and corrosion behavior of micro-arc oxidized Ti surface modified with hydrothermal treatment and chitosan coating

    International Nuclear Information System (INIS)

    Neupane, Madhav Prasad; Park, Il Song; Lee, Min Ho

    2014-01-01

    In the present work, we describe the surface modification of commercially pure titanium (CP-Ti) by a composite/multilayer coating approach for biomedical applications. CP-Ti samples were treated by micro-arc oxidation (MAO) and subsequently some of the samples were coated with chitosan (Chi) by dip coating method, while others were subjected to hydrothermal treatment (HT) followed by chitosan coating. The MAO, MAO/Chi, and MAO/HT/Chi coated Ti were characterized and their characteristics were compared with CP-Ti. X-ray diffraction and scanning electron microscopy were used to assess the structural and morphological characteristics. The average surface roughness was determined using a surface profilometer. The corrosion resistance of untreated and surface modified Ti in commercial saline at 298 K was evaluated by potentiodynamic polarization test. The results indicated that the chitosan coating is very well integrated with the MAO and MAO/HT coating by physically interlocking itself with the coated layer and almost sealed all the pores. The surface roughness of hydrothermally treated and chitosan coated MAO film was superior evidently to that with other sample groups. The corrosion studies demonstrated that the MAO, hydrothermally treated and chitosan coated sample enhanced the corrosion resistance of titanium. The result indicates that fabrication of hydrothermally treated MAO surface coatings with chitosan is a significant approach to protect the titanium from corrosion, hence enhancing the potential use of titanium as bio-implants. - Highlights: • Micro-arc oxidized (MAO) and hydrothermally treated (HT) Ti surfaces are coated with chitosan (Chi). • The MAO/HT/Chi surface exhibits pores sealing and enhanced the surface roughness. • The MAO/HT/Chi surface significantly increase the corrosion resistance. • The MAO/HT/Chi can be a potential surface of titanium for bio-implants

  5. Surface characteristics analysis of dry EDMed AISI D2 steel using modified tool design

    Energy Technology Data Exchange (ETDEWEB)

    Pragadish, N.; Kumar, M. Pradeep [Anna University, Chennai (China)

    2015-04-15

    A modified tool design is proposed which helps in drilling holes without any central core, and also enables the effective removal of the debris particles. Experiments were conducted on AISI D2 Steel using copper electrode as tool in both conventional EDM and dry EDM processes and the performance of both processes is compared. Experiments were designed using Taguchi's L27 orthogonal array. Discharge current (I), gap voltage (V), pulse on time (T{sub ON}), gas pressure (P) and tool rotational speed (N) were chosen as the various input parameters, and their effect on the material removal rate (MRR), surface roughness (SR), surface morphology, microstructure and elemental composition of the machined surface is analyzed. The experimental results show better surface characteristics in the surface machined under dry EDM process.

  6. Surface characteristics analysis of dry EDMed AISI D2 steel using modified tool design

    International Nuclear Information System (INIS)

    Pragadish, N.; Kumar, M. Pradeep

    2015-01-01

    A modified tool design is proposed which helps in drilling holes without any central core, and also enables the effective removal of the debris particles. Experiments were conducted on AISI D2 Steel using copper electrode as tool in both conventional EDM and dry EDM processes and the performance of both processes is compared. Experiments were designed using Taguchi's L27 orthogonal array. Discharge current (I), gap voltage (V), pulse on time (T ON ), gas pressure (P) and tool rotational speed (N) were chosen as the various input parameters, and their effect on the material removal rate (MRR), surface roughness (SR), surface morphology, microstructure and elemental composition of the machined surface is analyzed. The experimental results show better surface characteristics in the surface machined under dry EDM process.

  7. Electrochemical Biosensor Based on Boron-Doped Diamond Electrodes with Modified Surfaces

    Directory of Open Access Journals (Sweden)

    Yuan Yu

    2012-01-01

    Full Text Available Boron-doped diamond (BDD thin films, as one kind of electrode materials, are superior to conventional carbon-based materials including carbon paste, porous carbon, glassy carbon (GC, carbon nanotubes in terms of high stability, wide potential window, low background current, and good biocompatibility. Electrochemical biosensor based on BDD electrodes have attracted extensive interests due to the superior properties of BDD electrodes and the merits of biosensors, such as specificity, sensitivity, and fast response. Electrochemical reactions perform at the interface between electrolyte solutions and the electrodes surfaces, so the surface structures and properties of the BDD electrodes are important for electrochemical detection. In this paper, the recent advances of BDD electrodes with different surfaces including nanostructured surface and chemically modified surface, for the construction of various electrochemical biosensors, were described.

  8. Effects of modified surfaces produced at plasma-facing surface on hydrogen release behavior in the LHD

    Directory of Open Access Journals (Sweden)

    Y. Nobuta

    2017-08-01

    Full Text Available In the present study, an additional deuterium (D ion irradiation was performed against long-term samples mounted on the helical coil can and in the outer private region in the LHD during the 17th experimental campaign. Based on the release behavior of the D and hydrogen (H retained during the experimental campaign, the difference of release behavior at the top surface and in bulk of modified surfaces is discussed. Almost all samples on the helical coil can were erosion-dominant and some samples were covered with boron or carbon, while a very thick carbon films were formed in the outer private region. In the erosion-dominant area, the D desorbed at much lower temperatures compared to that of H retained during the LHD plasma operation. For the samples covered with boron, the D tended to desorb at lower temperatures compared to H. For the carbon deposition samples, the D desorbed at much higher temperatures compared to no deposition and boron-covered samples, which was very similar to that of H. The D retention capabilities at the top surface of carbon and boron films were 2–3 times higher than no deposition area. The results indicate that the retention and release behavior at the top surface of the modified layer can be different from that of bulk substrate material.

  9. Surface Modified Characteristics of the Tetracalcium Phosphate as Light-Cured Composite Resin Fillers

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Chen

    2014-01-01

    Full Text Available The objectives of this study are to characterize the properties of light-cured composite resins that are reinforced with whisker surface-modified particles of tetracalcium phosphate (TTCP and to investigate the influence of thermal cycling on the reinforced composites properties. The characteristics of ultimate diametral tensile strength (DTS, moduli, pH values, and fracture surfaces of the samples with different amounts of surface-modified TTCP (30%–60% were determined before and after thermal cycling between 5°C and 55°C in deionized water for 600 cycles. The trends of all groups were ductile prior to thermal cycling and the moduli of all groups increased after thermal cycling. The ductile property of the control group without filler was not significantly affected. Larger amounts of fillers caused the particles to aggregate, subsequently decreasing the resin’s ability to disperse external forces and leading to brittleness after thermal cycling. Therefore, the trend of composite resins with larger amounts of filler would become more brittle and exhibited higher moduli after thermal cycling. This developed composite resin with surface modified-TTCP fillers has the potential to be successful dental restorative materials.

  10. Protein arrangement on modified diamond-like carbon surfaces – An ARXPS study

    Energy Technology Data Exchange (ETDEWEB)

    Oosterbeek, Reece N., E-mail: reece.oosterbeek@auckland.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, Private Bag 92019 (New Zealand); Seal, Christopher K. [Light Metals Research Centre, The University of Auckland, Private Bag 92019 (New Zealand); Hyland, Margaret M. [Department of Chemical and Materials Engineering, The University of Auckland, Private Bag 92019 (New Zealand)

    2014-12-01

    Highlights: • DLC coatings were modified by Ar{sup +} ion sputtering and laser graphitisation. • The surface properties of the coatings were measured, and it was found that the above methods increased sp{sup 2} content and altered surface energy. • ARXPS was used to observe protein arrangement on the surface. • Polar CO/CN groups were seen to be segregated towards the interface, indicating they play an important role in bonding. • This segregation increased with increasing polar surface energy, indicating an increased net attraction between polar groups. - Abstract: Understanding the nature of the interface between a biomaterial implant and the biological fluid is an essential step towards creating improved implant materials. This study examined a diamond-like carbon coating biomaterial, the surface energy of which was modified by Ar{sup +} ion sputtering and laser graphitisation. The arrangement of proteins was analysed by angle resolved X-ray photoelectron spectroscopy, and the effects of the polar component of surface energy on this arrangement were observed. It was seen that polar groups (such as CN, CO) are more attracted to the coating surface due to the stronger polar interactions. This results in a segregation of these groups to the DLC–protein interface; at increasing takeoff angle (further from to DLC–protein interface) fewer of these polar groups are seen. Correspondingly, groups that interact mainly by dispersive forces (CC, CH) were found to increase in intensity as takeoff angle increased, indicating they are segregated away from the DLC–protein interface. The magnitude of the segregation was seen to increase with increasing polar surface energy, this was attributed to an increased net attraction between the solid surface and polar groups at higher polar surface energy (γ{sub S}{sup p})

  11. Protein arrangement on modified diamond-like carbon surfaces – An ARXPS study

    International Nuclear Information System (INIS)

    Oosterbeek, Reece N.; Seal, Christopher K.; Hyland, Margaret M.

    2014-01-01

    Highlights: • DLC coatings were modified by Ar + ion sputtering and laser graphitisation. • The surface properties of the coatings were measured, and it was found that the above methods increased sp 2 content and altered surface energy. • ARXPS was used to observe protein arrangement on the surface. • Polar CO/CN groups were seen to be segregated towards the interface, indicating they play an important role in bonding. • This segregation increased with increasing polar surface energy, indicating an increased net attraction between polar groups. - Abstract: Understanding the nature of the interface between a biomaterial implant and the biological fluid is an essential step towards creating improved implant materials. This study examined a diamond-like carbon coating biomaterial, the surface energy of which was modified by Ar + ion sputtering and laser graphitisation. The arrangement of proteins was analysed by angle resolved X-ray photoelectron spectroscopy, and the effects of the polar component of surface energy on this arrangement were observed. It was seen that polar groups (such as CN, CO) are more attracted to the coating surface due to the stronger polar interactions. This results in a segregation of these groups to the DLC–protein interface; at increasing takeoff angle (further from to DLC–protein interface) fewer of these polar groups are seen. Correspondingly, groups that interact mainly by dispersive forces (CC, CH) were found to increase in intensity as takeoff angle increased, indicating they are segregated away from the DLC–protein interface. The magnitude of the segregation was seen to increase with increasing polar surface energy, this was attributed to an increased net attraction between the solid surface and polar groups at higher polar surface energy (γ S p )

  12. Development of the removal technology for toxic heavy metal ions by surface-modified activated carbon

    International Nuclear Information System (INIS)

    Park, Geun Il; Song, Kee Chan; Kim, Kwang Wook; Kim, In Tae; Cho, Il Hoon; Kim, Joon Hyung

    2001-01-01

    Adsorption capacities of both radionuclides(uranium, cobalt) and toxic heavy metals (lead, cadmium and chromium) using double surface-modified activated carbon in wide pH ranges are extensively evaluated. Surface-modified activated carbons are classified as AC(as-received carbon), OAC(single surface-modified carbon with nitric acid solution) and OAC-Na(double surface-modified carbon with various alkali solutions). It is established that optimal condition for the second surface modification of OAC is to use the mixed solution of both NaOH and NaCl with total concentration of 0.1 N based on adsorption efficiencies of uranium and cobalt. Variations of adsorption efficiencies in pH ranges of 2∼10 and the adsorption capacities in batch adsorber and fixed bed for removal of both radionuclides and toxic heavy metals using OAC-Na were shown to be superior to that of the AC and OAC even in a low pH range. Capacity factors of OAC-Na for the removal of various metal ions are also excellent to that of AC or OAC. Quantitative analysis of capacity factors for each ions showed that adsorption capacity of OAC-Na increased by 30 times for uranium, 60 times for cobalt, 9 times for lead, 30 times for cadmium, 3 times for chromium compared to that of AC at pH 5, respectively. Adsorption capacity of OAC-Na is comparable to that of XAD-16-TAR used as commercial ion exchange resin

  13. Structure–Property Relationships of Inorganically Surface-Modified Zeolite Molecular Sieves for Nanocomposite Membrane Fabrication

    KAUST Repository

    Lydon, Megan E.

    2012-05-03

    A multiscale experimental study of the structural, compositional, and morphological characteristics of aluminosilicate (LTA) and pure-silica (MFI) zeolite materials surface-modified with MgO xH y nanostructures is presented. These characteristics are correlated with the suitability of such materials in the fabrication of LTA/Matrimid mixed-matrix membranes (MMMs) for CO 2/CH 4 separations. The four functionalization methods studied in this work produce surface nanostructures that may appear superficially similar under SEM observation but in fact differ considerably in shape, size, surface coverage, surface area/roughness, degree of attachment to the zeolite surface, and degree of zeolite pore blocking. The evaluation of these characteristics by a combination of TEM, HRTEM, N 2 physisorption, multiscale compositional analysis (XPS, EDX, and ICP-AES elemental analysis), and diffraction (ED and XRD) allows improved understanding of the origin of disparate gas permeation properties observed in MMMs made with four types of surface-modified zeolite LTA materials, as well as a rational selection of the method expected to result in the best enhancement of the desired properties (in the present case, CO 2/CH 4 selectivity increase without sacrificing permeability). A method based on ion exchange of the LTA with Mg 2+, followed by base-induced precipitation and growth of MgO xH y nanostructures, deemed "ion exchange functionalization" here, offers modified particles with the best overall characteristics resulting in the most effective MMMs. LTA/Matrimid MMMs containing ion exchange functionalized particles had a considerably higher CO 2/CH 4 selectivity (∼40) than could be obtained with the other functionalization techniques (∼30), while maintaining a CO 2 permeability of ∼10 barrers. A parallel study on pure silica MFI surface nanostructures is also presented to compare and contrast with the zeolite LTA case. © 2012 American Chemical Society.

  14. Wear characterization of a tool steel surface modified by melting and gaseous alloying

    International Nuclear Information System (INIS)

    Rizvi, S.A.

    1999-01-01

    Hot forging dies are subjected to laborious service conditions and so there is a need to explore means of improving die life to increase productivity and quality of forgings. Surface modification in order to produce wear resistant surface is an attractive method as it precludes the need to use expensive and highly alloyed steels. In this study, a novel, inexpensive surface modification technique is used to improve the tri biological properties of an H13 tool steel. Surface melting was achieved using a tungsten heat source and gaseous alloying produced under a shield of argon, carbon dioxide, carbon dioxide-argon mixture and nitrogen gases. The change in wear behaviour was compared through micro-hardness indentation measurements and using a dry sliding pin-on-plate wear testing machine. This study shows superior wear behaviour of the modified surfaces when compared to the untreated surfaces. The increase in wear resistance is attributed to the formation of carbides when surfaces are melted under a carbon dioxide shield. However, in the case of nitrogen and argon gaseous alloying, an increase in wear resistance can be attributed to an increase in surface hardness which in turn effects surface deformation behaviour. (author)

  15. Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

    Directory of Open Access Journals (Sweden)

    Cesar GAITAN-FONSECA

    2013-01-01

    Full Text Available Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS. Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA. The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT. Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

  16. Surface and protein analyses of normal human cell attachment on PIII-modified chitosan membranes

    International Nuclear Information System (INIS)

    Saranwong, N.; Inthanon, K.; Wongkham, W.; Wanichapichart, P.; Suwannakachorn, D.; Yu, L.D.

    2012-01-01

    Surface of chitosan membrane was modified with argon (Ar) and nitrogen (N) plasma immersion ion implantation (PIII) for human skin fibroblasts F1544 cell attachment. The modified surfaces were characterized by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Cell attachment patterns were evaluated by scanning electron microscopy (SEM). The enzyme-linked immunosorbent assay (ELISA) was used to quantify levels of focal adhesion kinase (FAK). The results showed that Ar PIII had an enhancement effect on the cell attachment while N-PIII had an inhibition effect. Filopodial analysis revealed more microfilament cytoplasmic spreading on the edge of cells attached on the Ar-treated membranes than N-treated membranes. Higher level FAK was found in Ar-treated membranes than that in N-treated membranes.

  17. Acute and subchronic toxicity analysis of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles

    Science.gov (United States)

    Venkatasubbu, Gopinath Devanand; Ramasamy, S; Gaddam, Pramod Reddy; Kumar, J

    2015-01-01

    Nanoparticles are widely used for targeted drug delivery applications. Surface modification with appropriate polymer and ligands is carried out to target the drug to the affected area. Toxicity analysis is carried out to evaluate the safety of the surface modified nanoparticles. In this study, paclitaxel attached, folic acid functionalized, polyethylene glycol modified hydroxyapatite and titanium dioxide nanoparticles were used for targeted drug delivery system. The toxicological behavior of the system was studied in vivo in rats and mice. Acute and subchronic studies were carried out. Biochemical, hematological, and histopathological analysis was also done. There were no significant alterations in the biochemical parameters at a low dosage. There was a small change in alkaline phosphatase (ALP) level at a high dosage. The results indicate a safe toxicological profile. PMID:26491315

  18. Fabrication of TiO_2-modified polytetrafluoroethylene ultrafiltration membranes via plasma-enhanced surface graft pretreatment

    International Nuclear Information System (INIS)

    Qian, Yingjia; Chi, Lina; Zhou, Weili; Yu, Zhenjiang; Zhang, Zhongzhi; Zhang, Zhenjia; Jiang, Zheng

    2016-01-01

    Graphical abstract: - Highlights: • Multifunctional TiO_2/PAA/PTFE ultrafiltration membrane was fabricated via tight coating of TiO_2 functional layer onto the plasma-assisted graft of PAA on PTFE. • The high water flux rate, remarkable enhanced ultrafiltration performance and excellent self-cleaning ability were demonstrated. • The formation of COO−Ti bidentate coordination between TiO_2 and PAA was responsible for the successful coating. - Abstract: Surface hydrophilic modification of polymer ultrafiltration membrane using metal oxide represents an effective yet highly challenging solution to improve water flux and antifouling performance. Via plasma-enhanced graft of poly acryl acid (PAA) prior to coating TiO_2, we successfully fixed TiO_2 functional thin layer on super hydrophobic polytetrafluoroethylene (PTFE) ultrafiltration (UF) membranes. The characterization results evidenced TiO_2 attached on the PTFE-based UF membranes through the chelating bidentate coordination between surface-grafted carboxyl group and Ti"4"+. The TiO_2 surface modification may greatly reduce the water contact angle from 115.8° of the PTFE membrane to 35.0° without degradation in 30-day continuous filtration operations. The novel TiO_2/PAA/PTFE membranes also exhibited excellent antifouling and self-cleaning performance due to the intrinsic hydrophilicity and photocatalysis properties of TiO_2, which was further confirmed by the photo-degradation of MB under Xe lamp irradiation.

  19. Fabrication of TiO2-modified polytetrafluoroethylene ultrafiltration membranes via plasma-enhanced surface graft pretreatment

    Science.gov (United States)

    Qian, Yingjia; Chi, Lina; Zhou, Weili; Yu, Zhenjiang; Zhang, Zhongzhi; Zhang, Zhenjia; Jiang, Zheng

    2016-01-01

    Surface hydrophilic modification of polymer ultrafiltration membrane using metal oxide represents an effective yet highly challenging solution to improve water flux and antifouling performance. Via plasma-enhanced graft of poly acryl acid (PAA) prior to coating TiO2, we successfully fixed TiO2 functional thin layer on super hydrophobic polytetrafluoroethylene (PTFE) ultrafiltration (UF) membranes. The characterization results evidenced TiO2 attached on the PTFE-based UF membranes through the chelating bidentate coordination between surface-grafted carboxyl group and Ti4+. The TiO2 surface modification may greatly reduce the water contact angle from 115.8° of the PTFE membrane to 35.0° without degradation in 30-day continuous filtration operations. The novel TiO2/PAA/PTFE membranes also exhibited excellent antifouling and self-cleaning performance due to the intrinsic hydrophilicity and photocatalysis properties of TiO2, which was further confirmed by the photo-degradation of MB under Xe lamp irradiation.

  20. Chemisorption of SO2 at the surface of In2O3 modified by zink

    International Nuclear Information System (INIS)

    Vinokurova, M.V.; Derlyukova, L.E.; Vinokurov, A.A.

    2005-01-01

    Chemisorption of SO 2 and O 2 at the surface of In 2 O 3 involving zink addition (0.4-2.7 at.%) are investigated in the temperature range 22-200 Deg C. No less than three forms of sorbed SO 2 are available at the surface of modified In 2 O 3 . Temperature effects on the ratio of forms of SO 2 sorption and, consequently, on varying the electric conductivity. Previous sorption of O 2 is favorable to the formation of donor form of chemisorbed SO 2 [ru

  1. Small-Angle Neutron Scattering Investigation of Growth Modifiers on Hydrate Crystal Surfaces

    Science.gov (United States)

    Sun, Thomas; Hutter, Jeffrey L.; Lin, M.; King, H. E., Jr.

    1998-03-01

    Hydrates are crystals consisting of small molecules enclathrated within an ice-like water cage. Suppression of their growth is important in the oil industry. The presence of small quantities of specific polymers during hydrate crystallization can induce a transition from an octahedral to planar growth habit. This symmetry breaking is surprising because of the suppression of two 111 planes relative to the other six crystallographically equivalent faces. To better understand the surface effects leading to this behavior, we have studied the surface adsorption of these growth-modifing polymers onto the hydrate crytals using SANS. The total hydrate surface area, as measured by Porod scattering, increases in the presence of the growth modifier, but, no significant increase in polymer concentration on the crystal surfaces is found. Implications for possible growth mechanisms will be discussed.

  2. Titania nanotube arrays surface-modified with ZnO for enhanced photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Nageri, Manoj; Kalarivalappil, Vijila; Vijayan, Baiju K.; Kumar, Viswanathan, E-mail: vkumar10@yahoo.co.in

    2016-05-15

    Highlights: • Heterostructures of TNA/ZnO synthesised through potentiostatic anodisation followed by hydrothermal method. • Evaluation of morphological features of the heterostructure with hydrothermal processing time. • Correlation of photocatalytic activity of the hetrostructure with its morphology and surface texture. - Abstract: Well ordered titanium dioxide nanotube arrays (TNA) of average diameter 129 nm and wall thickness of 25 nm were fabricated through potentiostatic anodisation of titanium (Ti) metal substrates. Such TNA were subsequently surface-modified with various amounts of zinc oxide (ZnO) nanopowders using hydrothermal technique to obtain heterogeneous TNA/ZnO nanostructures. The crystalline phase and surface microstructure of the heterostructures were determined by X-ray diffraction, Raman spectroscopy and scanning electron microscopy respectively. The morphology of the heterostructures strongly depended on the hydrothermal conditions employed. The photocatalytic activity of the heterostructures have also been investigated and correlated with their surface morphology and texture.

  3. Modified surface of titanium dioxide nanoparticles-based biosensor for DNA detection

    Science.gov (United States)

    Nadzirah, Sh.; Hashim, U.; Rusop, M.

    2018-05-01

    A new technique was used to develop a simple and selective picoammeter DNA biosensor for identification of E. coli O157:H7. This biosensor was fabricated from titanium dioxide nanoparticles that was synthesized by sol-gel method and spin-coated on silicon dioxide substrate via spinner. 3-Aminopropyl triethoxy silane (APTES) was used to modify the surface of TiO2. Simple surface modification approach has been applied; which is single dropping of APTES onto the TiO2 nanoparticles surface. Carboxyl modified probe DNA has been bind onto the surface of APTES/TiO2 without any amplifier element. Electrical signal has been used as the indicator to differentiate each step (surface modification of TiO2 and probe DNA immobilization). The I-V measurements indicate extremely low current (pico-ampere) flow through the device which is 2.8138E-10 A for pure TiO2 nanoparticles, 2.8124E-10 A after APTES modification and 3.5949E-10 A after probe DNA immobilization.

  4. Effect of Amelogenin Coating of a Nano-Modified Titanium Surface on Bioactivity

    Directory of Open Access Journals (Sweden)

    Chisato Terada

    2018-04-01

    Full Text Available The interactions between implants and host tissues depend on several factors. In particular, a growing body of evidence has demonstrated that the surface texture of an implant influences the response of the surrounding cells. The purpose of this study is to develop new implant materials aiming at the regeneration of periodontal tissues as well as hard tissues by coating nano-modified titanium with amelogenin, which is one of the main proteins contained in Emdogain®. We confirmed by quartz crystal microbalance evaluation that amelogenin is easy to adsorb onto the nano-modified titanium surface as a coating. Scanning electron microscopy, scanning probe microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy analyses confirmed that amelogenin coated the nano-modified titanium surface following alkali-treatment. In vitro evaluation using rat bone marrow and periodontal ligament cells revealed that the initial adhesion of both cell types and the induction of hard tissue differentiation such as cementum were improved by amelogenin coating. Additionally, the formation of new bone in implanted surrounding tissues was observed in in vivo evaluation using rat femurs. Together, these results suggest that this material may serve as a new implant material with the potential to play a major role in the advancement of clinical dentistry.

  5. Interaction between Palladium Nanoparticles and Surface-Modified Carbon Nanotubes: Role of Surface Functionalities

    DEFF Research Database (Denmark)

    Zhang, Bingsen; Shao, Lidong; Zhang, Wei

    2014-01-01

    degrees C. We focus on probing the effects of oxygen and nitrogen-containing functional groups on supported palladium nanoparticles (NPs) in the model catalytic system. The stability of palladium NPs supported on CNTs depends strongly on the surface properties of CNTs. Moreover, the oxygen...... feature, instability, and subtle response of the components upon application of an external field. Herein, we use insitu TEM, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy techniques to record the interaction in palladium on carbon nanotubes (CNTs) from room temperature to 600...

  6. Micro-PIV/LIF measurements on electrokinetically-driven flow in surface modified microchannels

    International Nuclear Information System (INIS)

    Ichiyanagi, Mitsuhisa; Sasaki, Seiichi; Sato, Yohei; Hishida, Koichi

    2009-01-01

    Effects of surface modification patterning on flow characteristics were investigated experimentally by measuring electroosmotic flow velocities, which were obtained by micron-resolution particle image velocimetry using a confocal microscope. The depth-wise velocity was evaluated by using the continuity equation and the velocity data. The microchannel was composed of a poly(dimethylsiloxane) chip and a borosilicate cover-glass plate. Surface modification patterns were fabricated by modifying octadecyltrichlorosilane (OTS) on the glass surface. OTS can decrease the electroosmotic flow velocity compared to the velocity in the glass microchannel. For the surface charge varying parallel to the electric field, the depth-wise velocity was generated at the boundary area between OTS and the glass surfaces. For the surface charge varying perpendicular to the electric field, the depth-wise velocity did not form because the surface charge did not vary in the stream-wise direction. The surface charge pattern with the oblique stripes yielded a three-dimensional flow in a microchannel. Furthermore, the oblique patterning was applied to a mixing flow field in a T-shaped microchannel, and mixing efficiencies were evaluated from heterogeneity degree of fluorescent dye intensity, which was obtained by laser-induced fluorescence. It was found that the angle of the oblique stripes is an important factor to promote the span-wise and depth-wise momentum transport and contributes to the mixing flow in a microchannel

  7. A surface-chemistry study of barium ferrite nanoplates with DBSa-modified surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lisjak, Darja, E-mail: darja.lisjak@ijs.si [Jožef Stefan Institute, Ljubljana (Slovenia); Ovtar, Simona; Kovač, Janez [Jožef Stefan Institute, Ljubljana (Slovenia); Gregoratti, Luca; Aleman, Belen; Amati, Matteo [Elettra – Sincrotrone Trieste S.C.p.A. di interesse nazionale, Trieste (Italy); Fanetti, Mattia [University of Nova Gorica, Nova Gorica (Slovenia); Istituto Officina dei Materiali CNR, Area Science Park, Trieste (Italy); Makovec, Darko [Jožef Stefan Institute, Ljubljana (Slovenia)

    2014-06-01

    Barium ferrite (BaFe{sub 12}O{sub 19}) is a ferrimagnetic oxide with a high magnetocrystalline anisotropy that can be exploited in magnetically aligned ceramics or films for self-biased magnetic applications. Magnetic alignment of the films can be achieved by the directed assembly of barium ferrite nanoplates. In this investigation the nanoplates were synthesized hydrothermally and suspended in 1-butanol using dodecylbenzene sulphonic acid (DBSa) as a surfactant. They were then deposited in an electric or magnetic field on flat substrates and exhibited a significant preferential alignment in the plane of the substrate, allowing a differentiation between the analysis of their basal and side planes using scanning photoelectron microscopy with a lateral resolution down to 100 nm. The surface chemistry of the nanoplates was additionally studied with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. For a comparison, bare barium ferrite nanoplates were also analyzed after decomposing the DBSa at 460 °C. The deviation of the surface chemistry from the stoichiometric composition was observed and the adsorption of the DBSa molecules on the nanoplates was confirmed with all three methods. Different types of bonding (physi- or chemisorption) were possible and considered with respect to the assembly of the barium ferrite nanoplates into anisotropic magnetic films.

  8. Improvement of surface acidity and structural regularity of Zr-modified mesoporous MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.F. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico)]. E-mail: chenlf2001@yahoo.com; Norena, L.E. [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico); Navarrete, J. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Wang, J.A. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico)

    2006-06-10

    This work reports the synthesis and surface characterization of a Zr-modified mesoporous MCM-41 solid with an ordered hexagonal arrangement, prepared through a templated synthesis route, using cetyltrimethylammonium chloride as the template. The surface features, crystalline structure, textural properties and surface acidity of the materials were characterized by in situ Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), N{sub 2} physisorption isotherms, {sup 29}Si MAS-NMR and in situ FT-IR of pyridine adsorption. It is evident that the surfactant cations inserted into the network of the solids during the preparation could be removed by calcination of the sample above 500 deg. C. The resultant material showed a large surface area of 680.6 m{sup 2} g{sup -1} with a uniform pore diameter distribution in a very narrow range centered at approximately 2.5 nm. Zirconium incorporation into the Si-MCM-41 framework, confirmed by {sup 29}Si MAS-NMR analysis, increased not only the wall thickness of the mesopores but also the long-range order of the periodically hexagonal structure. Both, Lewis and Broensted acid sites, were formed on the surface of the Zr-modified MCM-41 solid. Compared to Si-MCM-41 on which only very weak Lewis acid sites were formed, the densities of both Lewis and Broensted acid sites and the strength of the acidity on the Zr-modified sample were significantly increased, indicating that the incorporation of zirconium greatly enhances the acidity of the material.

  9. Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balances

    Science.gov (United States)

    Tang, G.; Bartlein, P. J.

    2012-08-01

    Satellite-based data, such as vegetation type and fractional vegetation cover, are widely used in hydrologic models to prescribe the vegetation state in a study region. Dynamic global vegetation models (DGVM) simulate land surface hydrology. Incorporation of satellite-based data into a DGVM may enhance a model's ability to simulate land surface hydrology by reducing the task of model parameterization and providing distributed information on land characteristics. The objectives of this study are to (i) modify a DGVM for simulating land surface water balances; (ii) evaluate the modified model in simulating actual evapotranspiration (ET), soil moisture, and surface runoff at regional or watershed scales; and (iii) gain insight into the ability of both the original and modified model to simulate large spatial scale land surface hydrology. To achieve these objectives, we introduce the "LPJ-hydrology" (LH) model which incorporates satellite-based data into the Lund-Potsdam-Jena (LPJ) DGVM. To evaluate the model we ran LH using historical (1981-2006) climate data and satellite-based land covers at 2.5 arc-min grid cells for the conterminous US and for the entire world using coarser climate and land cover data. We evaluated the simulated ET, soil moisture, and surface runoff using a set of observed or simulated data at different spatial scales. Our results demonstrate that spatial patterns of LH-simulated annual ET and surface runoff are in accordance with previously published data for the US; LH-modeled monthly stream flow for 12 major rivers in the US was consistent with observed values respectively during the years 1981-2006 (R2 > 0.46, p 0.52). The modeled mean annual discharges for 10 major rivers worldwide also agreed well (differences day method for snowmelt computation, the addition of the solar radiation effect on snowmelt enabled LH to better simulate monthly stream flow in winter and early spring for rivers located at mid-to-high latitudes. In addition, LH

  10. Permanent hydrophilic modification of polypropylene and poly(vinyl alcohol) films by vacuum ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Belmonte, Guilherme Kretzmann [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Charles, German [Centro de Química Aplicada (CEQUIMAP), Facultad de Ciencias Químicas, Unversidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Strumia, Miriam Cristina [Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IPQA-Conicet, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Weibel, Daniel Eduardo, E-mail: danielw@iq.ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil)

    2016-09-30

    Highlights: • Polypropylene and Poly(vinyl alcohol) were surface modified by vacuum ultraviolet (VUV) irradiation. • The hydrophilicity of the treated films was permanent and resisted aging for several months. • Grafting of styrene monomer was only observed in the VUV irradiated regions. • The obtained results showed the potential in the use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region. - Abstract: Polypropylene (PP) and Poly(vinyl alcohol) (PVA) both synthetics polymers but one of them biodegradable, were surface modified by vacuum ultraviolet (VUV) irradiation. After VUV irradiation in an inert nitrogen atmosphere, the films were exposed to oxygen gas. The treated films were characterized by water contact angle measurements (WCA), optical profilometry, FTIR-ATR, XPS, UPS and NEXAFS techniques. PP and PVA VUV-treated films reached superhydrophilic conditions (WCAs <10°) in about 30 min of irradiation under our experimental conditions. It was observed that when the WCAs reached about 35–40° the hydrophilicity was permanent in both polymers. These results contrasted with typical plasma treatments were a rapid hydrophobic recovery with aging time is usually observed. UPS and XPS data showed the presence of new functionalities on the PP and PVA surfaces that were assigned to COO, C=O, C−O and C=C functional groups. Finally, grafting of styrene (ST) as a typical monomer was tested on PP films. It was confirmed that only in the VUV irradiated region an efficient grafting of ST or polymerized ST was found. Outside the irradiated regions no ST grafted was observed. Our results showed the potential use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region.

  11. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    Science.gov (United States)

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

  12. Removal of selenium species from waters using various surface-modified natural particles and waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Nevzat O.; Tozum, Seda [Department of Environmental Engineering, Suleyman Demirel University, Isparta (Turkey)

    2012-07-15

    Waste red mud and natural pumice/volcanic slag particles were surface modified and their selenium adsorption from waters was investigated. Acid activation/heat treatment of original red mud (ORM) particles significantly increased their micropore and external surface area and cumulative volume of pores. Iron oxide coating of pumice/slags and acid activation of ORM decreased their pH{sub pzc} values and increased surface acidity. Selenite/selenate adsorption on iron oxide surfaces and acid activated red mud (AARM) was very fast with approximately first-order adsorption kinetics. Iron oxide coating of pumice/slag and acid activation of ORM particles significantly enhanced their selenite and selenate uptakes. Maximum Se adsorption capacities as high as 6.3 (mg Se/g adsorbent) were obtained by AARM. The extent of selenate uptakes by the surface modified particles was generally lower than those of selenite. Due to competition among Se species and other background water matrix for iron oxide adsorption sites, reduced selenite/selenate uptakes were found in natural water compared to single solute tests. Higher Se uptakes by iron oxide surfaces were found at pH 7.5 compared to pH 8.9, due to increased electrostatic repulsion among iron oxides and Se species at higher pH. The most effective adsorbents among the tested 17 different particles for Se uptake were AARM and iron oxide coated pumice. Se concentrations less than drinking water standards (5-10 {mu}g/L) can be achieved by these particles. These low-cost, natural, or recyclable waste particles appear to be promising adsorbents for Se removal after their surface modification. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Adsorption characteristics of N-nitrosodimethylamine from aqueous solution on surface-modified activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Xiaodong, Dai [Chemistry and Chemical Engineering School, China University of Petroleum, Dongying 257061, Shandong (China); Institute for Sustainability and Innovation, Victoria University, Melbourne, VIC 8001 (Australia); Zou, Linda [SA Water Centre for Water Management and Reuse, University of South Australia, Adelaide, SA5095 (Australia); Zifeng, Yan [Chemistry and Chemical Engineering School, China University of Petroleum, Dongying 257061, Shandong (China); Millikan, Mary [Institute for Sustainability and Innovation, Victoria University, Melbourne, VIC 8001 (Australia)

    2009-08-30

    This study investigated the removal of N-nitrosodimethylamine (NDMA) by an adsorption mechanism using commercially available activated carbons and surface-modified activated carbons. The effects of the modification on the properties of the activated carbon were studied by N{sub 2} adsorption/desorption, Diffuse Reflectance Infrared Fourier Transmission (DRIFT) analysis and X-Ray Photoelectron Spectroscopy (XPS). Adsorption experiments revealed that the activated carbons demonstrated a greater capacity for NDMA adsorption capacity than can be achieved using zeolite. The equilibrium data was fitted to the Freundlich equation and it was found that the adsorption capacity was significantly influenced by the micropore size, relative pore volume and surface characteristics. Adsorption experiments were conducted using unmodified and modified activated carbons. The results indicated that the adsorption capacity of NDMA can be significantly improved by heat treatment and doping of TiO{sub 2} particles. This was because the surface treatments yielded more hydrophobic sites and fewer oxygen-containing surface functional groups, and consequently an increased capacity for NDMA adsorption.

  14. Adsorption characteristics of N-nitrosodimethylamine from aqueous solution on surface-modified activated carbons

    International Nuclear Information System (INIS)

    Dai Xiaodong; Zou, Linda; Yan Zifeng; Millikan, Mary

    2009-01-01

    This study investigated the removal of N-nitrosodimethylamine (NDMA) by an adsorption mechanism using commercially available activated carbons and surface-modified activated carbons. The effects of the modification on the properties of the activated carbon were studied by N 2 adsorption/desorption, Diffuse Reflectance Infrared Fourier Transmission (DRIFT) analysis and X-Ray Photoelectron Spectroscopy (XPS). Adsorption experiments revealed that the activated carbons demonstrated a greater capacity for NDMA adsorption capacity than can be achieved using zeolite. The equilibrium data was fitted to the Freundlich equation and it was found that the adsorption capacity was significantly influenced by the micropore size, relative pore volume and surface characteristics. Adsorption experiments were conducted using unmodified and modified activated carbons. The results indicated that the adsorption capacity of NDMA can be significantly improved by heat treatment and doping of TiO 2 particles. This was because the surface treatments yielded more hydrophobic sites and fewer oxygen-containing surface functional groups, and consequently an increased capacity for NDMA adsorption.

  15. Modified SIMPLE algorithm for the numerical analysis of incompressible flows with free surface

    International Nuclear Information System (INIS)

    Mok, Jin Ho; Hong, Chun Pyo; Lee, Jin Ho

    2005-01-01

    While the SIMPLE algorithm is most widely used for the simulations of flow phenomena that take place in the industrial equipment or the manufacturing processes, it is less adopted for the simulations of the free surface flow. Though the SIMPLE algorithm is free from the limitation of time step, the free surface behavior imposes the restriction on the time step. As a result, the explicit schemes are faster than the implicit scheme in terms of computation time when the same time step is applied to, since the implicit scheme includes the numerical method to solve the simultaneous equations in its procedure. If the computation time of SIMPLE algorithm can be reduced when it is applied to the unsteady free surface flow problems, the calculation can be carried out in the more stable way and, in the design process, the process variables can be controlled based on the more accurate data base. In this study, a modified SIMPLE algorithm is presented for the free surface flow. The broken water column problem is adopted for the validation of the modified algorithm (MoSIMPLE) and for comparison to the conventional SIMPLE algorithm

  16. Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Henan; Zheng, Yang; Li, Yan, E-mail: liyan@buaa.edu.cn; Jiang, Chengbao

    2017-05-01

    Highlights: • Fe{sub 2}O{sub 3}/ZnO oxides were formed on the surface of Zn implanted pure Fe samples. • The corrosion rate of the pure Fe in SBF was increased after Zn implantation. • Cytocompatibility of the pure Fe was improved by Zn ion implantation. - Abstract: Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40–60 nm and Fe{sub 2}O{sub 3}/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (E{sub corr}) and a 10-fold increase in the corrosion current density (i{sub corr}) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

  17. Microstructure and erosion characteristic of nodular cast iron surface modified by tungsten inert gas

    International Nuclear Information System (INIS)

    Abboud, Jaafar Hadi

    2012-01-01

    Highlights: ► Local surface melting. ► Significant improvement in erosion resistance. ► The ductile behaviour was found. -- Abstract: The surface of nodular cast iron has been melted and rapidly solidified by Tungsten Inert Gas (TIG) process to produce a chilled structure of high hardness and better erosion resistance. Welding currents of magnitude 100, 150, and 200 A at a constant voltage of 72 have been used to melt the surface of nodular cast iron. Microstructural characterization, hardness measurements, and erosion wear tests have been performed on these modified surfaces as well as on the untreated material. Microstructural characterization has shown that surface melting resulted in complete or partial dissolution of the graphite nodules and resolidification of primary austenite dendrites, which undergo further decomposition into ferrite and cementite, and interdendritic of acicular eutectic; their microhardness measured across the melted depth ranged between 600 and 800 Hv. The scale of the dendrites and the interdendritic eutectic became coarser when a higher current is used. The results also indicated that remelting process by TIG improved erosion resistance by three to four times. Eroded surface observations of the as-received and TIG melted samples showed a ductile behavior with a maximum erosion rate at 30°. The fine microstructures obtained by the rapid cooling and the formation of a large amount of eutectic cementite instead of the graphite have contributed greatly to the plastic flow and consequently to the better erosion resistance of the TIG surface melted samples.

  18. Thermally controlled growth of surface nanostructures on ion-modified AIII-BV semiconductor crystals

    Science.gov (United States)

    Trynkiewicz, Elzbieta; Jany, Benedykt R.; Wrana, Dominik; Krok, Franciszek

    2018-01-01

    The primary motivation for our systematic study is to provide a comprehensive overview of the role of sample temperature on the pattern evolution of several AIII-BV semiconductor crystal (001) surfaces (i.e., InSb, InP, InAs, GaSb) in terms of their response to low-energy Ar+ ion irradiation conditions. The surface morphology and the chemical diversity of such ion-modified binary materials has been characterized by means of scanning electron microscopy (SEM). In general, all surface textures following ion irradiation exhibit transitional behavior from small islands, via vertically oriented 3D nanostructures, to smoothened surface when the sample temperature is increased. This result reinforces our conviction that the mass redistribution of adatoms along the surface plays a vital role during the formation and growth process of surface nanostructures. We would like to emphasize that this paper addresses in detail for the first time the topic of the growth kinetics of the nanostructures with regard to thermal surface diffusion, while simultaneously offering some possible approaches to supplementing previous studies and therein gaining a new insight into this complex issue. The experimental results are discussed with reference to models of the pillars growth, abutting on preferential sputtering, the self-sustained etch masking effect and the redeposition process recently proposed to elucidate the observed nanostructuring mechanism.

  19. Development of breathable hydrophobic/hydrophilic functional textiles

    NARCIS (Netherlands)

    Agrawal, P. (Pramod); Brink, G.J. (Ger)

    2013-01-01

    The proposed bi-functional protective structure intended to have hydrophilic interior towards the skin surface and hydrophobic exterior for protection, ensuring fast transfer of moisture between body and external environment. The sandwich structure is prepared using 100% wool jersey and varieties of

  20. On the PEEK composites reinforced by surface-modified nano-silica

    International Nuclear Information System (INIS)

    Lai, Y.H.; Kuo, M.C.; Huang, J.C.; Chen, M.

    2007-01-01

    The nano-sized silica fillers reinforced poly(ether ether ketone) (PEEK) composites were fabricated by means of compression molding technique. The nano-sized silica, measuring 30 nm in size, was firstly modified by surface pretreatment with stearic acid. The performances and properties of the resulting PEEK/SiO 2 nanocomposites were examined in terms of tensile loading, hardness, dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The modified nano-silica was seen to disperse more uniformly than the unmodified counterpart. The XRD patterns of the modified silica reinforced PEEK composites reveal a systematic shift toward higher angles, suggesting the smaller d-spacing of the PEEK crystallites. The coefficient of thermal expansion (CTE) becomes lowered when the content of the nano-silica increases. Furthermore, the CTE of the modified silica filled PEEK nanocomposites shows the higher CTE values. A logic model is proposed. The increment of the dynamic modulus for the PEEK nanocomposites is up to 40% at elevated temperatures from 100 to 250 deg. C, indicating the apparent improvement of elevated temperature mechanical properties

  1. Aflatoxin Toxicity Reduction in Feed by Enhanced Binding to Surface-Modified Clay Additives

    Science.gov (United States)

    Jaynes, William F.; Zartman, Richard E.

    2011-01-01

    Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (Kd = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (Kd = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (Kd = 13,800) and carnitine (Kd = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (Kd = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (Kd = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (Kd = 1340) or the untreated montmorillonite (Kd = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity. PMID:22069725

  2. Bio-active molecules modified surfaces enhanced mesenchymal stem cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Mobasseri, Rezvan; Tian, Lingling; Soleimani, Masoud; Ramakrishna, Seeram; Naderi-Manesh, Hossein

    2017-01-01

    Surface modification of the substrate as a component of in vitro cell culture and tissue engineering, using bio-active molecules including extracellular matrix (ECM) proteins or peptides derived ECM proteins can modulate the surface properties and thereby induce the desired signaling pathways in cells. The aim of this study was to evaluate the behavior of human bone marrow mesenchymal stem cells (hBM-MSCs) on glass substrates modified with fibronectin (Fn), collagen (Coll), RGD peptides (RGD) and designed peptide (R-pept) as bio-active molecules. The glass coverslips were coated with fibronectin, collagen, RGD peptide and R-peptide. Bone marrow mesenchymal stem cells were cultured on different substrates and the adhesion behavior in early incubation times was investigated using scanning electron microscopy (SEM) and confocal microscopy. The MTT assay was performed to evaluate the effect of different bio-active molecules on MSCs proliferation rate during 24 and 72 h. Formation of filopodia and focal adhesion (FA) complexes, two steps of cell adhesion process, were observed in MSCs cultured on bio-active molecules modified coverslips, specifically in Fn coated and R-pept coated groups. SEM image showed well adhesion pattern for MSCs cultured on Fn and R-pept after 2 h incubation, while the shape of cells cultured on Coll and RGD substrates indicated that they might experience stress condition in early hours of culture. Investigation of adhesion behavior, as well as proliferation pattern, suggests R-peptide as a promising bio-active molecule to be used for surface modification of substrate in supporting and inducing cell adhesion and proliferation. - Highlights: • Bioactive molecules modified surface is a strategy to design biomimicry scaffold. • Bi-functional Tat-derived peptide (R-pept) enhanced MSCs adhesion and proliferation. • R-pept showed similar influences to fibronectin on FA formation and attachment.

  3. Surface modified superparamagnetic nanoparticles: Interaction with fibroblasts in primary cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Chapa Gonzalez, Christian; Roacho Pérez, Jorge A.; Martínez Pérez, Carlos A.; Olivas Armendáriz, Imelda [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Jimenez Vega, Florinda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Castrejon Parga, Karen Y. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico); Garcia Casillas, Perla E., E-mail: pegarcia@uacj.mx [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua, México (Mexico)

    2014-12-05

    Highlights: • An inorganic layer before an organic material shell onto MNPs improves cell viability. • The coating type and the concentration of nanoparticles directly affect cell viability. • Modified magnetite nanoparticles with organic and inorganic materials was developed. - Abstract: The development of a variety of medical applications such as drug delivery, cell labeling, and medical imaging have been possible owing to the unique features exhibited by magnetic nanoparticles. Nanoparticle–cell interaction is related to the surface aspects of nanoparticle, which may be described based on their chemistry or inorganic/organic characteristics. The coating on particle surface reduces the inter-particle interactions and provides properties such as biocompatibility. Among the coating materials used for nanoparticles employed in biomedical applications, oleic acid is one of the most utilized due to its biocompatibility. However, a major drawback with this naturally occurring fatty acid is that it is easily oxidized by cells and this reduces their performance in biomedical applications. In order to avoid the direct contact of the cell with the magnetite particle, coating with an inorganic material prior to the oleic acid shell would be effective. This would retard the magnetite dissociation thereby improve the cell viability. Here we report our investigation on the effect of surface modified magnetite nanoparticles (MNPs) on the cell viability using primary cultures incubated with those particles. We prepared magnetite nanoparticles by chemical co-precipitation method; nanoparticle surface was first modified by silanol condensation followed by chemisorption of oleic acid. All nanostructures have a particle size less than 100 nm, depending on the material coating and superparamagnetic behavior. The saturated magnetizations (M{sub s}) of the magnetite samples coated with oleic acid (MAO; 49.15 emu/g) and double shell silica-oleic acid (MSAO; 46.16 emu/g) are

  4. Significant electrical control of amorphous oxide thin film transistors by an ultrathin Ti surface polarity modifier

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Byungsu [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Samsung Display Co. Ltd., Tangjeong, Chungcheongnam-Do 336-741 (Korea, Republic of); Choi, Yonghyuk; Shin, Seokyoon [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jeon, Heeyoung [Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Seo, Hyungtak, E-mail: hseo@ajou.ac.kr [Department of Materials Science and Engineering and Energy Systems Research, Ajou University, Suwon 443-739 (Korea, Republic of); Jeon, Hyeongtag, E-mail: hjeon@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-01-27

    We demonstrate an enhanced electrical stability through a Ti oxide (TiO{sub x}) layer on the amorphous InGaZnO (a-IGZO) back-channel; this layer acts as a surface polarity modifier. Ultrathin Ti deposited on the a-IGZO existed as a TiO{sub x} thin film, resulting in oxygen cross-binding with a-IGZO surface. The electrical properties of a-IGZO thin film transistors (TFTs) with TiO{sub x} depend on the surface polarity change and electronic band structure evolution. This result indicates that TiO{sub x} on the back-channel serves as not only a passivation layer protecting the channel from ambient molecules or process variables but also a control layer of TFT device parameters.

  5. Observation of modified radiative properties of cold atoms in vacuum near a dielectric surface

    International Nuclear Information System (INIS)

    Ivanov, V V; Cornelussen, R A; Heuvell, H B van Linden van den; Spreeuw, R J C

    2004-01-01

    We have observed a distance-dependent absorption linewidth of cold 87 Rb atoms close to a dielectric-vacuum interface. This is the first observation of modified radiative properties in vacuum near a dielectric surface. A cloud of cold atoms was created using a magneto-optical trap (MOT) and optical molasses cooling. Evanescent waves (EW) were used to observe the behaviour of the atoms near the surface. We observed an increase of the absorption linewidth by up to 25% with respect to the free-space value. Approximately half the broadening can be explained by cavity quantum electrodynamics (CQED) as an increase of the natural linewidth and inhomogeneous broadening. The remainder we attribute to local Stark shifts near the surface. By varying the characteristic EW length we have observed a distance dependence characteristic for CQED

  6. Luminescence stability of porous Si terminated by hydrophilic organic molecules

    Science.gov (United States)

    Matsumoto, Kimihisa; Kamiguchi, Masao; Kamiya, Kazuhide; Nomura, Takashi; Suzuki, Shinya

    2016-02-01

    The effects of the surface termination of a porous Si surface by propionic acid and by undecylenic acid on their hydrophilicity and luminescence stability were studied. In the measurements of the contact angle of water droplets on porous Si films, the hydrophilicity of porous Si is improved by the surface termination each types of organic molecule. The PL intensity of as-prepared porous Si decreased with increasing aging time in ambient air. As PL quenching involves PL blue shift and increasing Si-O bonds density, nonradiative recombination centers are formed in the surface oxide. After the hydrosilylation process of propionic acid and undecylenic acid, PL intensity decreased and became 30% that of as-prepared porous Si film. However, the PL intensity was stable and exceeded that of the as-prepared film after 1000 min of aging in the ambient air. The PL stabilities are contributed to the termination by organic molecules that inhibits surface oxidation.

  7. Chemical modification of poly(vinyl alcohol): evaluation of hydrophilic/lipophilic balance

    International Nuclear Information System (INIS)

    Aranha, Isabele B.; Lucas, Elizabete F.

    2001-01-01

    Poly(vinyl alcohol) terpolymers have been obtained by reaction of partially hydrolized poly(vinyl alcohol) with different acid chlorides. The objective is the preparation of polymers with slight differences in their hydrophilic/lipophilic balance and in the interfacial activities of their solutions. The chemical modifications were characterized by means of 1 H NMR and the polymer properties were evaluated in terms of changes in solubility and surface tension. By chemical modification, polymers with low percentage of hydrophobic group were obtained. The water-soluble polymers obtained did not have the surface tension of their solutions altered. The solubility of the modified polymers decreased markedly, even with low contents of hydrophobic groups. (author)

  8. Modified polarized geometrical attenuation model for bidirectional reflection distribution function based on random surface microfacet theory.

    Science.gov (United States)

    Liu, Hong; Zhu, Jingping; Wang, Kai

    2015-08-24

    The geometrical attenuation model given by Blinn was widely used in the geometrical optics bidirectional reflectance distribution function (BRDF) models. Blinn's geometrical attenuation model based on symmetrical V-groove assumption and ray scalar theory causes obvious inaccuracies in BRDF curves and negatives the effects of polarization. Aiming at these questions, a modified polarized geometrical attenuation model based on random surface microfacet theory is presented by combining of masking and shadowing effects and polarized effect. The p-polarized, s-polarized and unpolarized geometrical attenuation functions are given in their separate expressions and are validated with experimental data of two samples. It shows that the modified polarized geometrical attenuation function reaches better physical rationality, improves the precision of BRDF model, and widens the applications for different polarization.

  9. Influence of surface modified basalt fiber on strength of cinder lightweight aggregate concrete

    Science.gov (United States)

    Xiao, Liguang; Li, Jiheng; Liu, Qingshun

    2017-12-01

    In order to improve the bonding and bridging effect between volcanic slag lightweight aggregate concrete cement and basalt fiber, The basalt fiber was subjected to etching and roughening treatment by NaOH solution, and the surface of the basalt fiber was treated with a mixture of sodium silicate and micro-silica powder. The influence of modified basalt fiber on the strength of volcanic slag lightweight aggregate concrete was systematically studied. The experimental results show that the modified basalt fiber volcanic slag lightweight aggregate concrete has a flexural strength increased by 47%, the compressive strength is improved by 16% and the toughness is increased by 27% compared with that of the non-fiber.

  10. Surface-enhanced Raman difference between bombesin and its modified analogues on the colloidal and electrochemically roughen silver surfaces.

    Science.gov (United States)

    Podstawka, Edyta; Ozaki, Yukihiro

    2008-10-01

    In this article, surface-enhanced Raman scattering (SERS) spectra of bombesin (BN) and its six modified analogues ([D-Phe(12)]BN, [Tyr(4)]BN, [Tyr(4),D-Phe(12)]BN, [D-Phe(12),Leu(14)]BN, [Leu(13)-(R)-Leu(14)]BN, and [Lys(3)]BN) on a colloidal silver surface are reported and compared with SERS spectra of these species immobilized onto an ellectrochemically roughen silver electrode. Changes in enhancement and wavenumber of proper bands upon adsorption on different silver surfaces are consistent with BN and its analogues adsorption primarily through Trp(8). Slightly different adsorption states of these molecules are observed depending upon natural amino acids substitution. For example, the indole ring in all the peptides interacts with silver nanoparticles in a edge-on orientation. It is additionally coordinated to the silver through the N(1)--H bond for all the peptides, except [Phe(12)]BN. This is in contrary to the results obtained for the silver roughen electrode that show direct but not strong N(1)--H/Ag interaction for all peptides except [D-Phe(12),Leu(14)]BN and [Leu(13)-(R)-Leu(14)]BN. For BN only C==O is not involved in the chemical coordination with the colloidal surface. [Lys(3)]BN and BN also adsorb with the C--N bond of NH(2) group normal and horizontal, respectively, to the colloidal surface, whereas C--NH(2) in other peptides is tilted to this surface. Also, the Trp(8) --CH(2)-- moiety of only [Tyr(4)]BN, [Lys(3)]BN, and [Tyr(4),D-Phe(12)]BN coordinates to Ag, whereas the Phe(12) ring of [Phe(12)]BN, [Tyr(4),D-Phe(12)]BN, and [D-Phe(12),Leu(14)]BN assists in the peptides binding only on the colloidal silver. (c) 2008 Wiley Periodicals, Inc.

  11. Modified titanium surface with gelatin nano gold composite increases osteoblast cell biocompatibility

    International Nuclear Information System (INIS)

    Lee, Young-Hee; Bhattarai, Govinda; Aryal, Santosh; Lee, Nan-Hee; Lee, Min-Ho; Kim, Tae-Gun; Jhee, Eun-Chung; Kim, Hak-Yong; Yi, Ho-Keun

    2010-01-01

    This study examined the gelatin nano gold (GnG) composite for surface modification of titanium in addition to insure biocompatibility on dental implants or biomaterials. The GnG composite was constructed by gelatin and hydrogen tetrachloroaurate in presence of reducing agent, sodium borohydrate (NabH 4 ). The GnG composite was confirmed by UV-VIS spectroscopy and transmission electron microscopy (TEM). A dipping method was used to modify the titanium surface by GnG composite. Surface was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The MC-3T3 E1 cell viability was assessed by trypan blue and the expression of proteins to biocompatibility were analyzed by Western blotting. The GnG composite showed well dispersed character, the strong absorption at 530 nm, roughness, regular crystal and clear C, Na, Cl, P, and Au signals onto titanium. Further, this composite allowed MC-3T3 E1 growth and viability compared to gelatin and pure titanium. It induced ERK activation and the expression of cell adherent molecules, FAK and SPARC, and growth factor, VEGF. However, GnG decreased the level of SAPK/JNK. This shows that GnG composite coated titanium surfaces have a good biocompatibility for osteoblast growth and attachment than in intact by simple and versatile dipping method. Furthermore, it offers good communication between cell and implant surfaces by regulating cell signaling and adherent molecules, which are useful to enhance the biocompatibility of titanium surfaces.

  12. An in vitro bacterial adhesion assessment of surface-modified medical-grade PVC.

    Science.gov (United States)

    Asadinezhad, Ahmad; Novák, Igor; Lehocký, Marián; Sedlarík, Vladimir; Vesel, Alenka; Junkar, Ita; Sáha, Petr; Chodák, Ivan

    2010-06-01

    Medical-grade polyvinyl chloride was surface modified by a multistep physicochemical approach to improve bacterial adhesion prevention properties. This was fulfilled via surface activation by diffuse coplanar surface barrier discharge plasma followed by radical graft copolymerization of acrylic acid through surface-initiated pathway to render a structured high density brush. Three known antibacterial agents, bronopol, benzalkonium chloride, and chlorhexidine, were then individually coated onto functionalized surface to induce biological properties. Various modern surface probe techniques were employed to explore the effects of the modification steps. In vitro bacterial adhesion and biofilm formation assay was performed. Escherichia coli strain was found to be more susceptible to modifications rather than Staphylococcus aureus as up to 85% reduction in adherence degree of the former was observed upon treating with above antibacterial agents, while only chlorhexidine could retard the adhesion of the latter by 50%. Also, plasma treated and graft copolymerized samples were remarkably effective to diminish the adherence of E. coli. Copyright 2010 Elsevier B.V. All rights reserved.

  13. [Study on preparation and physicochemical properties of surface modified sintered bone].

    Science.gov (United States)

    Li, Jingfeng; Zheng, Qixin; Guo, Xiaodong

    2012-06-01

    The aim of this study is to investigate a new method for preparing a biomimetic bone material-surface modified sintered bovine cancellous bone, and to improve its bioactivity as a tissue engineering bone. The prepared sintered bovine cancellous bones with the same size were randomly divided into two groups, immersing in 1 and 1. 5 times simulated body fluid (SBF), respectively. The three time periods of soak time were 7, 14, and 21 days. After sintered bone was dried, the surface morphology of sintered bone and surface mineralization composition were observed under scanning electron microscopy (SEM). By comparing the effect of surface modification of sintered bone materials, we chose the most ideal material and studied its pore size, the rate of the porosity, the compress and bend intensity. And then the material and the sintered bone material without surface modification were compared. The study indicated that sintered bone material immersed in SBF (1.5 times) for 14 days showed the best effect of surface modification, retaining the original physico-chemical properties of sintered bone.

  14. Protein arrangement on modified diamond-like carbon surfaces - An ARXPS study

    Science.gov (United States)

    Oosterbeek, Reece N.; Seal, Christopher K.; Hyland, Margaret M.

    2014-12-01

    Understanding the nature of the interface between a biomaterial implant and the biological fluid is an essential step towards creating improved implant materials. This study examined a diamond-like carbon coating biomaterial, the surface energy of which was modified by Ar+ ion sputtering and laser graphitisation. The arrangement of proteins was analysed by angle resolved X-ray photoelectron spectroscopy, and the effects of the polar component of surface energy on this arrangement were observed. It was seen that polar groups (such as CN, CO) are more attracted to the coating surface due to the stronger polar interactions. This results in a segregation of these groups to the DLC-protein interface; at increasing takeoff angle (further from to DLC-protein interface) fewer of these polar groups are seen. Correspondingly, groups that interact mainly by dispersive forces (CC, CH) were found to increase in intensity as takeoff angle increased, indicating they are segregated away from the DLC-protein interface. The magnitude of the segregation was seen to increase with increasing polar surface energy, this was attributed to an increased net attraction between the solid surface and polar groups at higher polar surface energy (γSp).

  15. Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

    Science.gov (United States)

    Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

    2017-05-01

    Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

  16. Modified Titanium Surface-Mediated Effects on Human Bone Marrow Stromal Cell Response

    Directory of Open Access Journals (Sweden)

    Amol Chaudhari

    2013-11-01

    Full Text Available Surface modification of titanium implants is used to enhance osseointegration. The study objective was to evaluate five modified titanium surfaces in terms of cytocompatibility and pro-osteogenic/pro-angiogenic properties for human mesenchymal stromal cells: amorphous microporous silica (AMS, bone morphogenetic protein-2 immobilized on AMS (AMS + BMP, bio-active glass (BAG and two titanium coatings with different porosity (T1; T2. Four surfaces served as controls: uncoated Ti (Ti, Ti functionalized with BMP-2 (Ti + BMP, Ti surface with a thickened titanium oxide layer (TiO2 and a tissue culture polystyrene surface (TCPS. The proliferation of eGFP-fLuc (enhanced green fluorescence protein-firefly luciferase transfected cells was tracked non-invasively by fluorescence microscopy and bio-luminescence imaging. The implant surface-mediated effects on cell differentiation potential was tracked by determination of osteogenic and angiogenic parameters [alkaline phosphatase (ALP; osteocalcin (OC; osteoprotegerin (OPG; vascular endothelial growth factor-A (VEGF-A]. Unrestrained cell proliferation was observed on (unfunctionalized Ti and AMS surfaces, whereas BAG and porous titanium coatings T1 and T2 did not support cell proliferation. An important pro-osteogenic and pro-angiogenic potential of the AMS + BMP surface was observed. In contrast, coating the Ti surface with BMP did not affect the osteogenic differentiation of the progenitor cells. A significantly slower BMP-2 release from AMS compared to Ti supports these findings. In the unfunctionalized state, Ti was found to be superior to AMS in terms of OPG and VEGF-A production. AMS is suggested to be a promising implant coating material for bioactive agents delivery.

  17. Surface Photochemistry: Benzophenone as a Probe for the Study of Modified Cellulose Fibres

    Directory of Open Access Journals (Sweden)

    L. F. Vieira Ferreira

    2007-01-01

    Full Text Available This work reports the use of benzophenone, a very well characterized probe, to study new hosts (i.e., modified celluloses grafted with alkyl chains bearing 12 carbon atoms by surface esterification. Laser-induced room temperature luminescence of air-equilibrated or argon-purged solid powdered samples of benzophenone adsorbed onto the two modified celluloses, which will be named C12-1500 and C12-1700, revealed the existence of a vibrationally structured phosphorescence emission of benzophenone in the case where ethanol was used for sample preparation, while a nonstructured emission of benzophenone exists when water was used instead of ethanol. The decay times of the benzophenone emission vary greatly with the solvent used for sample preparation and do not change with the alkylation degree in the range of 1500–1700 micromoles of alkyl chains per gram of cellulose. When water was used as a solvent for sample preparation, the shortest lifetime for the benzophenone emission was observed; this result is similar to the case of benzophenone adsorbed onto the “normal” microcrystalline cellulose surface, with this latter case previously reported by Vieira Ferreira et al. in 1995. This is due to the more efficient hydrogen abstraction reaction from the glycoside rings of cellulose when compared with hydrogen abstraction from the alkyl chains of the modified celluloses. Triplet-triplet transient absorption of benzophenone was obtained in both cases and is the predominant absorption immediately after laser pulse, while benzophenone ketyl radical formation occurs in a microsecond time scale both for normal and modified celluloses.

  18. 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

    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...

  19. Multivalent-Counterion-Induced Surfactant Multilayer Formation at Hydrophobic and Hydrophilic Solid-Solution Interfaces.

    Science.gov (United States)

    Penfold, Jeffrey; Thomas, Robert K; Li, Peixun; Xu, Hui; Tucker, Ian M; Petkov, Jordan T; Sivia, Devinderjit S

    2015-06-23

    Surface multilayer formation from the anionic-nonionic surfactant mixture of sodium dodecyl dioxyethylene sulfate, SLES, and monododecyl dodecaethylene glycol, C12E12, by the addition of multivalent Al(3+) counterions at the solid-solution interface is observed and characterized by neutron reflectivity, NR. The ability to form surface multilayer structures on hydrophobic and hydrophilic silica and cellulose surfaces is demonstrated. The surface multilayer formation is more pronounced and more well developed on the hydrophilic and hydrophobic silica surfaces than on the hydrophilic and hydrophobic cellulose surfaces. The less well developed multilayer formation on the cellulose surfaces is attributed to the greater surface inhomogeneities of the cellulose surface which partially inhibit lateral coherence and growth of the multilayer domains at the surface. The surface multilayer formation is associated with extreme wetting properties and offers the potential for the manipulation of the solid surfaces for enhanced adsorption and control of the wetting behavior.

  20. Electrochemical characteristics of Shewanella loihica on carbon nanotubes-modified graphite surfaces

    International Nuclear Information System (INIS)

    Zhang, Xiaoming; Epifanio, Monica; Marsili, Enrico

    2013-01-01

    Highlights: • We deposited CNT coatings on graphite electrode by electrophoretic deposition. • CNT coating increased extracellular electron transfer in Shewanella loihica biofilms. • Thick electroactive biofilms hinder the electroactivity of CNT coatings. -- Abstract: High specific surface and electrocatalytic activity of the electrode surface favour extracellular electron transfer from electrochemically active biofilms to polarized electrodes. We coated layer-by-layer carbon nanotubes (CNTs) on graphite electrodes through electrophoretic deposition, thus increasing the electrocatalytic activity. After determining the optimal number of CNT layers through electrochemical methods, we grew Shewanella loihica PV-4 biofilms on the CNT-coated electrodes to quantify the increase in extracellular electron transfer rate compared with unmodified electrodes. Current density on CNT-modified electrodes was 1.7 times higher than that observed on unmodified electrodes after 48 h from inoculation. Rapid microbial cells attachment on CNT-coated electrodes, as determined from scanning electronic microscopy, explained the rapid increase of the current. Also, the CNT reduced the charge transfer resistance of the graphite electrodes, as measured by Electrochemical Impedance Spectroscopy. However, the electrocatalytic activity of the CNT-coated electrode decreased as the biofilm grew thicker and covered the CNT-coating. These result confirmed that surface-modified electrodes improve the electron transfer rate in thin biofilms (<5 μm), but are not feasible for power production in microbial fuel cells, where the biofilm thickness is much higher

  1. The electrochemical behavior and surface structure of titanium electrodes modified by ion beams

    International Nuclear Information System (INIS)

    Huang, G.F.; Xie, Z.; Huang, W.Q.; Yang, S.B.; Zhao, L.H.

    2004-01-01

    Industrial grade titanium modified by ion implantation and sputtering was used as electrodes. The effect of ion beam modification on the electrochemical behavior and surface structure of electrodes was investigated. Also discussed is the hydrogen evolution process of the electrode in acidic solution. Several ions such as Fe + , C + , W + , Ni + and others, were implanted into the electrode. The electrochemical tests were carried out in 1N H 2 SO 4 solution at 30±1 deg. C. The electrode potential was measured versus a saturate calomel electrode as a function of immersion time. The cathodic polarization curves were measured by the stable potential static method. The surface layer composition and the chemical state of the electrodes were also investigated by Auger electron spectrometer (AES) and X-ray photoelectron spectroscopy (XPS) technique. The results show that: (1) the stability of modified electrodes depends on the active elements introduced by ion implantation and sputtering deposition. (2) The hydrogen evolution activity of industrial grade titanium may be improved greatly by ion beam modification. (3) Ion beam modification changed the composition and the surface state of electrodes over a certain depth range and forms an activity layer having catalytic hydrogen evolution, which inhibited the absorption of hydrogen and formation of titanium hydride. Thus promoted hydrogen evolution and improved the hydrogen evolution catalytic activity in industrial grade titanium

  2. Studies on surface grafting of AAc/SSS binary monomers onto polytetrafluoroethylene by dielectric barrier discharge initiation

    International Nuclear Information System (INIS)

    Xi Zhenyu; Xu Youyi; Zhu Liping; Liu Fu; Zhu Baoku

    2008-01-01

    Polytetrafluoroethylene (PTFE) films were pre-treated by dielectric barrier discharge in atmospheric pressure with air as carrier gas. And then the hydrophilic sulfonate groups were introduced by the single step grafting method with binary monomer solution of acrylic acid (AAc) and sodium 4-styrenesulfonate (SSS). The effects of binary monomer ratio, reaction solution concentration and polymerization time on the degree of grafting were investigated. The surface chemical change was determined by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). Morphological changes on the film surface were described using field emitting scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface hydrophilicity of the modified film was characterized through water contact angle measurement. It was found that the water contact angle of the film surface reduced significantly when compared with the original one, indicating the introduction of hydrophilic groups and improvement of the surface hydrophilicity

  3. Investigation of the biofouling properties of several algae on different textured chemical modified silicone surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jihai [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, Wenjie, E-mail: zhaowj@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Peng, Shusen; Zeng, Zhixiang; Zhang, Xin [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wu, Xuedong, E-mail: xdwu@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xue, Qunji [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2014-08-30

    Highlights: • Engineered pillars, pits and grooves spaced 3–12 μm apart were fabricated on siloxane modified acrylic resin films. • The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. • The feature size and geometry displayed a substantial correlation with the antifouling properties. • A comparatively physical fouling deterrent mechanism was analyzed. - Abstract: Engineered pillars, pits and grooves spaced 3, 6, 9 and 12 μm apart were fabricated on siloxane modified acrylic resin films. The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. These films showed various antifouling performances to Ulothrix, Closterium and Navicula. For Navicula (length: 10–12 μm), the feature size and geometry displayed a substantial correlation with the antifouling properties. The film with pillars spaced 3 μm reduced Navicula settlement by 73% compared to the control surface. For Closterium (length: 45–55 μm), their responses were governed by the same underlying thermodynamic principles as wettability, the largest reduction in Closterium, 81%, was obtained on the surface with grooves spaced 12 μm apart. For Ulothrix (length: 5–8 mm), the surface also showed the best antifouling performance, the reduction ratio of the settlement on the surface with grooves spaced 12 μm apart could even reach 92%. At last, physical fouling deterrent mechanisms for the films with various textures were analyzed in detail. The feature size and geometry display a substantial correlation with the antifouling properties when the size of fouling algae is close to the textures. With the increasing size for algae, antifouling performance was getting better on surface with pillars or grooves because the algae are bridged between two or more features other than stabilizing its entire mass on one single feature or able to settle between features.

  4. Investigation of the biofouling properties of several algae on different textured chemical modified silicone surfaces

    International Nuclear Information System (INIS)

    Xu, Jihai; Zhao, Wenjie; Peng, Shusen; Zeng, Zhixiang; Zhang, Xin; Wu, Xuedong; Xue, Qunji

    2014-01-01

    Highlights: • Engineered pillars, pits and grooves spaced 3–12 μm apart were fabricated on siloxane modified acrylic resin films. • The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. • The feature size and geometry displayed a substantial correlation with the antifouling properties. • A comparatively physical fouling deterrent mechanism was analyzed. - Abstract: Engineered pillars, pits and grooves spaced 3, 6, 9 and 12 μm apart were fabricated on siloxane modified acrylic resin films. The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. These films showed various antifouling performances to Ulothrix, Closterium and Navicula. For Navicula (length: 10–12 μm), the feature size and geometry displayed a substantial correlation with the antifouling properties. The film with pillars spaced 3 μm reduced Navicula settlement by 73% compared to the control surface. For Closterium (length: 45–55 μm), their responses were governed by the same underlying thermodynamic principles as wettability, the largest reduction in Closterium, 81%, was obtained on the surface with grooves spaced 12 μm apart. For Ulothrix (length: 5–8 mm), the surface also showed the best antifouling performance, the reduction ratio of the settlement on the surface with grooves spaced 12 μm apart could even reach 92%. At last, physical fouling deterrent mechanisms for the films with various textures were analyzed in detail. The feature size and geometry display a substantial correlation with the antifouling properties when the size of fouling algae is close to the textures. With the increasing size for algae, antifouling performance was getting better on surface with pillars or grooves because the algae are bridged between two or more features other than stabilizing its entire mass on one single feature or able to settle between features

  5. Effects of various surfactants on the dispersion stability and electrical conductivity of surface modified graphene

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, Md. Elias [WCU Program, Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kuila, Tapas [Surface Engineering and Tribology, CSIR – Central Mechanical Engineering Research Institute, Durgapur 721 302 (India); Nayak, Ganesh Chandra [Department of Applied Chemistry, ISM Dhanbad, Dhanbad 826 004, Jharkhand (India); Kim, Nam Hoon [Department of Hydrogen and Fuel Cell Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Ku, Bon-Cheol [Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Dunsan-ri, Bongdong-eup, Wanju-gun, Jeollabuk-do 864-9 (Korea, Republic of); Lee, Joong Hee, E-mail: jhl@chonbuk.ac.kr [WCU Program, Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Department of Hydrogen and Fuel Cell Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2013-06-15

    Highlights: ► Water dispersible graphene has been prepared using ionic and non-ionic surfactants. ► XPS and FTIR spectra analysis confirm surface modification and reduction of GO. ► The highest water dispersibility is observed in the graphene modified with of SDBS. ► The best properties of modified graphene is achieved with GO/surfactant ratio of two. -- Abstract: Ionic and non-ionic surfactant functionalized, water dispersible graphene were prepared to investigate the effects on the dispersion stability and electrical conductivity of graphene. In this study, sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate and 4-(1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol (Triton X-100) were used as ionic and non-ionic surfactants. The effects of surfactant concentrations on the dispersibility and electrical conductivity of the surface modified graphene were investigated. The dispersion stability of SDBS functionalized graphene (SDBS-G) was found to be best in water at 1.5 mg ml{sup −1}. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis indicate that the presence of surfactants does not prevent the reduction of graphene oxide (GO). These measurements also demonstrated that the surfactants were present on the surface of graphene, resulting in the formation of functionalized graphene. The thickness of different functionalized graphene was measured by Atomic force microscopy and varied significantly with different surfactants. The thermal properties of the functionalized graphene were also found to be dependent on the nature of the surfactants. The electrical conductivity of SDBS-G (108 S m{sup −1}) was comparatively higher than SDS and Triton X-100 functionalized graphene.

  6. Optical, Physical, and Chemical Properties of Surface Modified Titanium Dioxide Powders

    Science.gov (United States)

    2011-02-01

    PROPERTIES OF SURFACE MODIFIED TITANIUM DIOXIDE POWDERS fwn Scivrxc fa SciWcrrs Brendan G. DeLacy RESEARCH AND TECHNOLOGY DIRECTORATE David R. Redding ...NUMBER 5c PROGRAM ELEMENT NUMBER 6. AUTHOR(S) DeLacy, Brendan G. (SAIC) Redding , David R. (ECBC); and Matthews. Joshua 5d. PROJECT NUMBER...X3,300?t>5flm* ** aJI ^-15 SEf Figure 7 - SEM Image #1 of CR-470 •i i .#1. • ^ iW i > hp ^•R^^^Ay *£ $ ^< W^# K HB8 %^ vj\\ X

  7. Behaviour of human endothelial cells on surface modified NiTi alloy.

    Science.gov (United States)

    Plant, Stuart D; Grant, David M; Leach, Lopa

    2005-09-01

    Intravascular stents are being designed which utilise the shape memory properties of NiTi alloy. Despite the clinical advantages afforded by these stents their application has been limited by concerns about the large nickel ion content of the alloy. In this study, the surface chemistry of NiTi alloy was modified by mechanical polishing and oxidising heat treatments and subsequently characterised using X-ray photon spectroscopy (XPS). The effect of these surfaces on monolayer formation and barrier integrity of human umbilical vein endothelial cells (HUVEC) was then assessed by confocal imaging of the adherens junctional molecule VE-cadherin, perijunctional actin and permeability to 42kDa dextrans. Dichlorofluoroscein assays were used to measure oxidative stress in the cells. XPS analysis of NiTi revealed its surface to be dominated by TiO(2). However, where oxidation had occurred after mechanical polishing or post polishing heat treatments at 300 and 400 degrees C in air, a significant amount of metallic nickel or nickel oxide species (10.5 and 18.5 at%) remained on the surface. Exposure of HUVECs to these surfaces resulted in increased oxidative stress within the cells, loss of VE-cadherin and F-actin and significantly increased paracellular permeability. These pathological phenomena were not found in cells grown on NiTi which had undergone heat treatment at 600 degrees C. At this temperature thickening of the TiO(2) layer had occurred due to diffusion of titanium ions from the bulk of the alloy, displacing nickel ions to sub-surface areas. This resulted in a significant reduction in nickel ions detectable on the sample surface (4.8 at%). This study proposes that the integrity of human endothelial monolayers on NiTi is dependent upon the surface chemistry of the alloy and that this can be manipulated, using simple oxidising heat treatments.

  8. Surface science and model catalysis with ionic liquid-modified materials.

    Science.gov (United States)

    Steinrück, H-P; Libuda, J; Wasserscheid, P; Cremer, T; Kolbeck, C; Laurin, M; Maier, F; Sobota, M; Schulz, P S; Stark, M

    2011-06-17

    Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A multi-scale modeling of surface effect via the modified boundary Cauchy-Born model

    Energy Technology Data Exchange (ETDEWEB)

    Khoei, A.R., E-mail: arkhoei@sharif.edu; Aramoon, A.

    2012-10-01

    In this paper, a new multi-scale approach is presented based on the modified boundary Cauchy-Born (MBCB) technique to model the surface effects of nano-structures. The salient point of the MBCB model is the definition of radial quadrature used in the surface elements which is an indicator of material behavior. The characteristics of quadrature are derived by interpolating data from atoms laid in a circular support around the quadrature, in a least-square scene. The total-Lagrangian formulation is derived for the equivalent continua by employing the Cauchy-Born hypothesis for calculating the strain energy density function of the continua. The numerical results of the proposed method are compared with direct atomistic and finite element simulation results to indicate that the proposed technique provides promising results for modeling surface effects of nano-structures. - Highlights: Black-Right-Pointing-Pointer A multi-scale approach is presented to model the surface effects in nano-structures. Black-Right-Pointing-Pointer The total-Lagrangian formulation is derived by employing the Cauchy-Born hypothesis. Black-Right-Pointing-Pointer The radial quadrature is used to model the material behavior in surface elements. Black-Right-Pointing-Pointer The quadrature characteristics are derived using the data at the atomistic level.

  10. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

    2016-07-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

  11. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    International Nuclear Information System (INIS)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C.

    2016-01-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

  12. Photoluminescence investigation of ZnO quantum dots surface modified with silane coupling agent as a capping agent

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, E., E-mail: e.moghaddam@merc.ac.ir; Youzbashi, A.A; Kazemzadeh, A.; Eshraghi, M.J.

    2015-12-15

    This report presents the luminescence measurement results of surface modified zinc oxide quantum dots (ZnO QDs) performed with different concentrations of 3-aminopropyltriethoxysilane (APTES) as a capping agent. Surface modification was performed by an in situ procedure on the surface of ZnO QDs in a sol gel solution route. The modified samples were characterized by various analytical techniques such as XRD, TEM, FT-IR, and UV–vis spectroscopy. Surface modification efficiency was experimentally investigated by variation of the photoluminescence) PL (emission intensities observed by changing the capping agent concentration. In order to investigate the effectiveness of the capping agent on the stability of the QDs, The PL spectra of the surface modified ZnO QDs were compared with that of unmodified ZnO QDs. Molecular layer of this type and similar silane based molecules with a variety of surface terminations that have the same molecular attachment schemes should enable interface engineering in optimizing the chemical selectivity of ZnO biosensors or electrical and optical properties of ZnO-polymer hybrid films. - Highlights: • Surface modification of ZnO QDs resulted in the small- size QDs (around 2 nm). • Surface modification resulted in the enhancement of the UV emission upon quenching the visible emission. • Surface modification efficiency was decreased with reduction of the QD size • Intensified stability of the surface modified ZnO QDs was obtained from surface modification.

  13. Modified polarimetric bidirectional reflectance distribution function with diffuse scattering: surface parameter estimation

    Science.gov (United States)

    Zhan, Hanyu; Voelz, David G.

    2016-12-01

    The polarimetric bidirectional reflectance distribution function (pBRDF) describes the relationships between incident and scattered Stokes parameters, but the familiar surface-only microfacet pBRDF cannot capture diffuse scattering contributions and depolarization phenomena. We propose a modified pBRDF model with a diffuse scattering component developed from the Kubelka-Munk and Le Hors et al. theories, and apply it in the development of a method to jointly estimate refractive index, slope variance, and diffuse scattering parameters from a series of Stokes parameter measurements of a surface. An application of the model and estimation approach to experimental data published by Priest and Meier shows improved correspondence with measurements of normalized Mueller matrix elements. By converting the Stokes/Mueller calculus formulation of the model to a degree of polarization (DOP) description, the estimation results of the parameters from measured DOP values are found to be consistent with a previous DOP model and results.

  14. Potential dependent adhesion forces on bare and underpotential deposition modified electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, J.M.; Hsieh, S.J.; Monahan, J.; Gewirth, A.A. [Univ. of Illinois, Urbana, IL (United States)

    1998-12-03

    Adhesion force measurements are used to determine the potential dependence of the force of adhesion between a Si{sub 3}N{sub 4} cantilever and a Au(111) surface modified by the underpotential deposition (upd) of Bi or Cu in acid solution or by oxide formation. The measured work of adhesion is near zero for most of the potential region examined in Bi upd but rises after the formation of a full Bi monolayer. The work of adhesion is high at positive potentials for Cu upd but then decreases as the Cu partial and full monolayers are formed. The work of adhesion is low in the oxide region on Au(111) but rises following the sulfate disordering transition at 1.1 V vs NHE. These results are interpreted in terms of the degree of solvent order on the electrode surface.

  15. Dithiocarbamate Self-Assembled Monolayers as Efficient Surface Modifiers for Low Work Function Noble Metals

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Dominik; Schäfer, Tobias; Schulz, Philip; Jung, Sebastian; Rittich, Julia; Mokros, Daniel; Segger, Ingolf; Maercks, Franziska; Effertz, Christian; Mazzarello, Riccardo; Wuttig, Matthias

    2016-09-06

    Tuning the work function of the electrode is one of the crucial steps to improve charge extraction in organic electronic devices. Here, we show that N,N-dialkyl dithiocarbamates (DTC) can be effectively employed to produce low work function noble metal electrodes. Work functions between 3.1 and 3.5 eV are observed for all metals investigated (Cu, Ag, and Au). Ultraviolet photoemission spectroscopy (UPS) reveals a maximum decrease in work function by 2.1 eV as compared to the bare metal surface. Electronic structure calculations elucidate how the complex interplay between intrinsic dipoles and dipoles induced by bond formation generates such large work function shifts. Subsequently, we quantify the improvement in contact resistance of organic thin film transistor devices with DTC coated source and drain electrodes. These findings demonstrate that DTC molecules can be employed as universal surface modifiers to produce stable electrodes for electron injection in high performance hybrid organic optoelectronics.

  16. Iron carbide on titania surface modified with group VA oxides as Fischer-Tropsch catalysts

    International Nuclear Information System (INIS)

    Wachs, I.E.; Fiato, R.A.; Chersich, C.C.

    1986-01-01

    A catalyst is described comprising iron carbide supported on a surface modified titania wherein the support comprises an oxide of a metal selected form the group consisting of niobium, vanadium, tantalum or mixture thereof supported on the titania wherein at least a portion of the supported oxide of niobium, vanandium, tantalum or mixture is in a non-crystalline form. The amount of the supported oxide ranges from about 0.5 to 25 weight percent metal oxide on the titania support based on the total support composition and the catalyst contains at least about 2 milligrams of iron, calculated as Fe/sub 2/O/sub 3/, per square meter of support surface

  17. Bone induction by surface-double-modified true bone ceramics in vitro and in vivo

    International Nuclear Information System (INIS)

    Li, Jingfeng; Chen, Liaobin; Deng, Yu; Zheng, Qixin; Guo, Xiaodong; Zou, Zhenwei; Liu, Yudong; Lan, Shenghui

    2013-01-01

    True bone ceramic (TBC), obtained by twice sintering fresh bovine cancellous bone at high temperatures, is an osteoconductive and bioactive bone substitute material that exhibits excellent biocompatibility with hard tissue. The authors have previously synthesized a novel BMP-2-related peptide, P24, and found that it could enhance the osteoblastic differentiation of cells. The objective of the present study was to construct a double-modified TBC via mineralization into simulated body fluid and P24 incorporation for enhanced bone formation. In vitro experiments revealed that surface mineralization-modified (SMM) TBC scaffolds demonstrated efficiency for sustained release of P24. The P24/SMM-TBC composite exhibited increased osteogenic activity by cell adhesion rate determination, MTT assay, alkaline phosphatase staining, and calcium nodule staining with alizarin red compared with SMM-TBC and TBC. In vivo studies showed that the P24/SMM-TBC composite scaffold promoted significant bone defect repair, in marked contrast to stand-alone SMM-TBC and TBC, based on the results of radiographic evaluation and histological examination. These findings indicate that SMM-TBC is a good scaffold for the controlled release of P24 and that the P24/SMM-TBC composite could improve the adhesion, proliferation and differentiation of cells and repair bone defects. The double-modified P24/SMM-TBC composite biomaterial shows potential for clinical application in bone tissue engineering. (paper)

  18. Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Jin, E-mail: jinxxwang@263.net [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Nan [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-11-15

    Highlights: • The dopamine/PEI film with controlled amine density was successfully prepared. • The DNA aptamer was assembled onto the film via electrostatic incorporation. • The A@DPfilmscanspecificallyandeffectivelycaptureEPCs. • The A@DP film can support the survival of ECs, control the hyperplasia of SMCs. • The dynamic/co-culture models are useful for studying cells competitive adhesion. - Abstract: Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

  19. Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

    International Nuclear Information System (INIS)

    Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si; Wang, Jin; Huang, Nan

    2016-01-01

    Highlights: • The dopamine/PEI film with controlled amine density was successfully prepared. • The DNA aptamer was assembled onto the film via electrostatic incorporation. • The A@DPfilmscanspecificallyandeffectivelycaptureEPCs. • The A@DP film can support the survival of ECs, control the hyperplasia of SMCs. • The dynamic/co-culture models are useful for studying cells competitive adhesion. - Abstract: Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

  20. A modified captive bubble method for determining advancing and receding contact angles

    International Nuclear Information System (INIS)

    Xue, Jian; Shi, Pan; Zhu, Lin; Ding, Jianfu; Chen, Qingmin; Wang, Qingjun

    2014-01-01

    Graphical abstract: - Highlights: • A modified captive bubble method for determining advancing and receding contact angle is proposed. • We have designed a pressure chamber with a pressure control system to the original experimental. • The modified method overcomes the deviation of the bubble in the traditional captive bubble method. • The modified captive bubble method allows a smaller error from the test. - Abstract: In this work, a modification to the captive bubble method was proposed to test the advancing and receding contact angle. This modification is done by adding a pressure chamber with a pressure control system to the original experimental system equipped with an optical angle mater equipped with a high speed CCD camera, a temperature control system and a computer. A series of samples with highly hydrophilic, hydrophilic, hydrophobic and superhydrophobic surfaces were prepared. The advancing and receding contact angles of these samples with highly hydrophilic, hydrophilic, and hydrophobic surfaces through the new methods was comparable to the result tested by the traditional sessile drop method. It is proved that this method overcomes the limitation of the traditional captive bubble method and the modified captive bubble method allows a smaller error from the test. However, due to the nature of the captive bubble technique, this method is also only suitable for testing the surface with advancing or receding contact angle below 130°

  1. A modified captive bubble method for determining advancing and receding contact angles

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Jian; Shi, Pan; Zhu, Lin [Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Eduction, Nanjing 210093 (China); Ding, Jianfu [Security and Disruptive Technologies, National Research Council Canada, 1200 Montreal Road, Ottawa, K1A 0R6, Ontario (Canada); Chen, Qingmin [Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Eduction, Nanjing 210093 (China); Wang, Qingjun, E-mail: njuwqj@nju.edu.cn [Key Laboratory of High Performance Polymer Materials and Technology (Nanjing University), Ministry of Eduction, Nanjing 210093 (China)

    2014-03-01

    Graphical abstract: - Highlights: • A modified captive bubble method for determining advancing and receding contact angle is proposed. • We have designed a pressure chamber with a pressure control system to the original experimental. • The modified method overcomes the deviation of the bubble in the traditional captive bubble method. • The modified captive bubble method allows a smaller error from the test. - Abstract: In this work, a modification to the captive bubble method was proposed to test the advancing and receding contact angle. This modification is done by adding a pressure chamber with a pressure control system to the original experimental system equipped with an optical angle mater equipped with a high speed CCD camera, a temperature control system and a computer. A series of samples with highly hydrophilic, hydrophilic, hydrophobic and superhydrophobic surfaces were prepared. The advancing and receding contact angles of these samples with highly hydrophilic, hydrophilic, and hydrophobic surfaces through the new methods was comparable to the result tested by the traditional sessile drop method. It is proved that this method overcomes the limitation of the traditional captive bubble method and the modified captive bubble method allows a smaller error from the test. However, due to the nature of the captive bubble technique, this method is also only suitable for testing the surface with advancing or receding contact angle below 130°.

  2. Neutral hydrophilic cathode catalyst binders for microbial fuel cells

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Improving oxygen reduction in microbial fuel cell (MFC) cathodes requires a better understanding of the effects of the catalyst binder chemistry and properties on performance. A series of polystyrene-b-poly(ethylene oxide) (PS-b-PEO) polymers with systematically varying hydrophilicity were designed to determine the effect of the hydrophilic character of the binder on cathode performance. Increasing the hydrophilicity of the PS-b-PEO binders enhanced the electrochemical response of the cathode and MFC power density by ∼15%, compared to the hydrophobic PS-OH binder. Increased cathode performance was likely a result of greater water uptake by the hydrophilic binder, which would increase the accessible surface area for oxygen reduction. Based on these results and due to the high cost of PS-b-PEO, the performance of an inexpensive hydrophilic neutral polymer, poly(bisphenol A-co-epichlorohydrin) (BAEH), was examined in MFCs and compared to a hydrophilic sulfonated binder (Nafion). MFCs with BAEH-based cathodes with two different Pt loadings initially (after 2 cycles) had lower MFC performance (1360 and 630 mW m-2 for 0.5 and 0.05 mg Pt cm-2) than Nafion cathodes (1980 and 1080 mW m -2 for 0.5 and 0.05 mg Pt cm-2). However, after long-term operation (22 cycles, 40 days), power production of each cell was similar (∼1200 and 700-800 mW m-2 for 0.5 and 0.05 mg Pt cm-2) likely due to cathode biofouling that could not be completely reversed through physical cleaning. While binder chemistry could improve initial electrochemical cathode performance, binder materials had less impact on overall long-term MFC performance. This observation suggests that long-term operation of MFCs will require better methods to avoid cathode biofouling. © 2011 The Royal Society of Chemistry.

  3. Performance enhancement in organic photovoltaic solar cells using iridium (Ir) ultra-thin surface modifier (USM)

    Science.gov (United States)

    Pandey, Rina; Lim, Ju Won; Kim, Jung Hyuk; Angadi, Basavaraj; Choi, Ji Won; Choi, Won Kook

    2018-06-01

    In this study, Iridium (Ir) metallic layer as an ultra-thin surface modifier (USM) was deposited on ITO coated glass substrate using radio frequency magnetron sputtering for improving the photo-conversion efficiency of organic photovoltaic cells. Ultra-thin Ir acts as a surface modifier replacing the conventional hole transport layer (HTL) PEDOT:PSS in organic photovoltaic (OPV) cells with two different active layers P3HT:PC60BM and PTB7:PC70BM. The Ir USM (1.0 nm) coated on ITO glass substrate showed transmittance of 84.1% and work function of >5.0 eV, which is higher than that of ITO (4.5-4.7 eV). The OPV cells with Ir USM (1.0 nm) exhibits increased power conversion efficiency of 3.70% (for P3HT:PC60BM active layer) and 7.28% (for PTB7:PC70BM active layer) under 100 mW/cm2 illumination (AM 1.5G) which are higher than those of 3.26% and 6.95% for the same OPV cells but with PEDOT:PSS as HTL instead of Ir USM. The results reveal that the chemically stable Ir USM layer could be used as an alternative material for PEDOT:PSS in organic photovoltaic cells.

  4. Surface treatment of NiTi shape memory alloy by modified advanced oxidation process

    Institute of Scientific and Technical Information of China (English)

    CHU Cheng-lin; WANG Ru-meng; YIN Li-hong; PU Yue-pu; DONG Yin-sheng; GUO Chao; SHENG Xiao-bo; LIN Ping-hua; CHU Paul-K

    2009-01-01

    A modified advanced oxidation process(AOP) utilizing a UV/electrochemically-generated peroxide system was used to fabricate titania films on chemically polished NiTi shape memory alloy(SMA). The microstructure and biomedical properties of the film were characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), inductively-coupled plasma mass spectrometry(ICPMS), hemolysis analysis, and blood platelet adhesion test. It is found that the modified AOP has a high processing effectiveness and can result in the formation of a dense titania film with a Ni-free zone near its top surface. In comparison, Ni can still be detected on the outer NiTi surface by the conventional AOP using the UV/H2O2 system. The depth profiles of O, Ni, Ti show that the film possesses a smooth graded interface structure next to the NiTi substrate and this structure enhances the mechanical stability of titania film. The titania film can dramatically reduce toxic Ni ion release and also improve the hemolysis resistance and thromboresistance of biomedical NiTi SMA.

  5. Catalytic Micromotors Moving Near Polyelectrolyte-Modified Substrates: The Roles of Surface Charges, Morphology, and Released Ions.

    Science.gov (United States)

    Wei, Mengshi; Zhou, Chao; Tang, Jinyao; Wang, Wei

    2018-01-24

    Synthetic microswimmers, or micromotors, are finding potential uses in a wide range of applications, most of which involve boundaries. However, subtle yet important effects beyond physical confinement on the motor dynamics remain less understood. In this letter, glass substrates were functionalized with positively and negatively charged polyelectrolytes, and the dynamics of micromotors moving close to the modified surfaces was examined. Using acoustic levitation and numerical simulation, we reveal how the speed of a chemically propelled micromotor slows down significantly near a polyelectrolyte-modified surface by the combined effects of surface charges, surface morphology, and ions released from the films.

  6. Surface-modified reduced graphene oxide electrodes for capacitors by ionic liquids and their electrochemical properties

    International Nuclear Information System (INIS)

    Kim, Jieun; Kim, Seok

    2014-01-01

    Highlights: • Reduced graphene oxide surface was modified by introduction of ionic liquids. • Microstructure and capacitance of modified electrode were dependent on the ionic liquids contents. • Modification gives electrode better charge transport and higher specific capacitance. • Modified electrode showed the better capacitive performance such as rate capability and cycle stability. - Abstract: In this work, reduced graphene oxide (rGO)/ionic liquids (IL) composites with different weight ratios of IL to rGO were synthesized by a simple method. In these composites, IL contributed to the exfoliation of rGO sheets and to the improvement of the electrochemical properties of the resulting composites by enhancing the ion diffusion and charge transport. The structure of the composites was examined by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM images showed that IL was coated on the surface of rGO in a translucent manner. The electrochemical analysis of the prepared composites was carried out by performing cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). Among the prepared composites, the one with a weight ratio of rGO to IL of 1:7 showed the highest specific capacitance of 147.5 F g −1 at a scan rate of 10 mV s −1 . In addition, the rate capability and cycle performance of the composites were enhanced compared to pristine rGO. These enhanced properties make the composites suitable as electrode materials for the better performance supercapacitors

  7. Fabrication of TiO{sub 2}-modified polytetrafluoroethylene ultrafiltration membranes via plasma-enhanced surface graft pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Yingjia [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Chi, Lina, E-mail: lnchi@sjtu.edu.cn [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Zhou, Weili; Yu, Zhenjiang [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang, Zhongzhi [College of Chemical Engineering, China University of Petroleum, Beijing 102249 (China); Zhang, Zhenjia [School of Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Jiang, Zheng, E-mail: z.jiang@soton.ac.uk [Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2016-01-01

    Graphical abstract: - Highlights: • Multifunctional TiO{sub 2}/PAA/PTFE ultrafiltration membrane was fabricated via tight coating of TiO{sub 2} functional layer onto the plasma-assisted graft of PAA on PTFE. • The high water flux rate, remarkable enhanced ultrafiltration performance and excellent self-cleaning ability were demonstrated. • The formation of COO−Ti bidentate coordination between TiO{sub 2} and PAA was responsible for the successful coating. - Abstract: Surface hydrophilic modification of polymer ultrafiltration membrane using metal oxide represents an effective yet highly challenging solution to improve water flux and antifouling performance. Via plasma-enhanced graft of poly acryl acid (PAA) prior to coating TiO{sub 2}, we successfully fixed TiO{sub 2} functional thin layer on super hydrophobic polytetrafluoroethylene (PTFE) ultrafiltration (UF) membranes. The characterization results evidenced TiO{sub 2} attached on the PTFE-based UF membranes through the chelating bidentate coordination between surface-grafted carboxyl group and Ti{sup 4+}. The TiO{sub 2} surface modification may greatly reduce the water contact angle from 115.8° of the PTFE membrane to 35.0° without degradation in 30-day continuous filtration operations. The novel TiO{sub 2}/PAA/PTFE membranes also exhibited excellent antifouling and self-cleaning performance due to the intrinsic hydrophilicity and photocatalysis properties of TiO{sub 2}, which was further confirmed by the photo-degradation of MB under Xe lamp irradiation.

  8. Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balances

    Directory of Open Access Journals (Sweden)

    G. Tang

    2012-08-01

    Full Text Available Satellite-based data, such as vegetation type and fractional vegetation cover, are widely used in hydrologic models to prescribe the vegetation state in a study region. Dynamic global vegetation models (DGVM simulate land surface hydrology. Incorporation of satellite-based data into a DGVM may enhance a model's ability to simulate land surface hydrology by reducing the task of model parameterization and providing distributed information on land characteristics. The objectives of this study are to (i modify a DGVM for simulating land surface water balances; (ii evaluate the modified model in simulating actual evapotranspiration (ET, soil moisture, and surface runoff at regional or watershed scales; and (iii gain insight into the ability of both the original and modified model to simulate large spatial scale land surface hydrology. To achieve these objectives, we introduce the "LPJ-hydrology" (LH model which incorporates satellite-based data into the Lund-Potsdam-Jena (LPJ DGVM. To evaluate the model we ran LH using historical (1981–2006 climate data and satellite-based land covers at 2.5 arc-min grid cells for the conterminous US and for the entire world using coarser climate and land cover data. We evaluated the simulated ET, soil moisture, and surface runoff using a set of observed or simulated data at different spatial scales. Our results demonstrate that spatial patterns of LH-simulated annual ET and surface runoff are in accordance with previously published data for the US; LH-modeled monthly stream flow for 12 major rivers in the US was consistent with observed values respectively during the years 1981–2006 (R2 > 0.46, p < 0.01; Nash-Sutcliffe Coefficient > 0.52. The modeled mean annual discharges for 10 major rivers worldwide also agreed well (differences < 15% with observed values for these rivers. Compared to a degree-day method for snowmelt computation, the addition of the solar radiation effect on snowmelt

  9. Mechanical, Thermal Degradation, and Flammability Studies on Surface Modified Sisal Fiber Reinforced Recycled Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Arun Kumar Gupta

    2012-01-01

    Full Text Available The effect of surface treated sisal fiber on the mechanical, thermal, flammability, and morphological properties of sisal fiber (SF reinforced recycled polypropylene (RPP composites was investigated. The surface of sisal fiber was modified with different chemical reagent such as silane, glycidyl methacrylate (GMA, and O-hydroxybenzene diazonium chloride (OBDC to improve the compatibility with the matrix polymer. The experimental results revealed an improvement in the tensile strength to 11%, 20%, and 31.36% and impact strength to 78.72%, 77%, and 81% for silane, GMA, and OBDC treated sisal fiber reinforced recycled Polypropylene (RPP/SF composites, respectively, as compared to RPP. The thermogravimetric analysis (TGA, differential scanning calorimeter (DSC, and heat deflection temperature (HDT results revealed improved thermal stability as compared with RPP. The flammability behaviour of silane, GMA, and OBDC treated SF/RPP composites was studied by the horizontal burning rate by UL-94. The morphological analysis through scanning electron micrograph (SEM supports improves surface interaction between fiber surface and polymer matrix.

  10. Dispersing surface-modified imogolite nanotubes in polar and non-polar solvents

    Science.gov (United States)

    Li, Ming; Brant, Jonathan A.

    2018-02-01

    Furthering the development of nanocomposite structures, namely membranes for water treatment applications, requires that methods be developed to ensure nanoparticle dispersion in polar and non-polar solvents, as both are widely used in associated synthesis techniques. Here, we report on a two-step method to graft polyvinylpyrrolidone (PVP), and a one-step method for octadecylphosphonic acid (OPA), onto the outer surfaces of imogolite nanotubes. The goal of these approaches was to improve and maintain nanotube dispersion in polymer compatible polar and non-polar solvents. The PVP coating modified the imogolite surface charge from positive to weakly negative at pH ≤ 9; the OPA made it weakly positive at acidic pH values to negative at pH ≥ 7. The PVP surface coating stabilized the nanotubes through steric hindrance in polar protic, dipolar aprotic, and chloroform. In difference to the PVP, the OPA surface coating allowed the nanotubes to be dispersed in n-hexane and chloroform, but not in the polar solvents. The lack of miscibility in the polar solvents, as well as the better dispersion in n-hexane, was attributed to the stronger hydrophobicity of the OPA polymer relative to the PVP. [Figure not available: see fulltext.

  11. NOx Direct Decomposition: Potentially Enhanced Thermodynamics and Kinetics on Chemically Modified Ferroelectric Surfaces

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2014-03-01

    NOx are regulated pollutants produced during automotive combustion. As part of an effort to design catalysts for NOx decomposition that operate in oxygen rich environment and permit greater fuel efficiency, we study chemistry of NOx on (001) ferroelectric surfaces. Changing the polarization at such surfaces modifies electronic properties and leads to switchable surface chemistry. Using first principles theory, our previous work has shown that addition of catalytic RuO2 monolayer on ferroelectric PbTiO3 surface makes direct decomposition of NO thermodynamically favorable for one polarization. Furthermore, the usual problem of blockage of catalytic sites by strong oxygen binding is overcome by flipping polarization that helps desorb the oxygen. We describe a thermodynamic cycle for direct NO decomposition followed by desorption of N2 and O2. We provide energy barriers and transition states for key steps of the cycle as well as describing their dependence on polarization direction. We end by pointing out how a switchable order parameter of substrate,in this case ferroelectric polarization, allows us to break away from some standard compromises for catalyst design(e.g. the Sabatier principle). This enlarges the set of potentially catalytic metals. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  12. Uniform surface-to-line integral reduction of physical optics for curved surfaces by modified edge representation with higher-order correction

    Science.gov (United States)

    Lyu, Pengfei; Ando, Makoto

    2017-09-01

    The modified edge representation is one of the equivalent edge currents approximation methods for calculating the physical optics surface radiation integrals in diffraction analysis. The Stokes' theorem is used in the derivation of the modified edge representation from the physical optics for the planar scatterer case, which implies that the surface integral is rigorously reduced into the line integral of the modified edge representation equivalent edge currents, defined in terms of the local shape of the edge. On the contrary, for curved surfaces, the results of radiation integrals depend upon the global shape of the scatterer. The physical optics surface integral consists of two components, from the inner stationary phase point and the edge. The modified edge representation is defined independently from the orientation of the actual edge, and therefore, it could be available not only at the edge but also at the arbitrary points on the scatterer except the stationary phase point where the modified edge representation equivalent edge currents becomes infinite. If stationary phase point exists inside the illuminated region, the physical optics surface integration is reduced into two kinds of the modified edge representation line integrations, along the edge and infinitesimally small integration around the inner stationary phase point, the former and the latter give the diffraction and reflection components, respectively. The accuracy of the latter has been discussed for the curved surfaces and published. This paper focuses on the errors of the former and discusses its correction. It has been numerically observed that the modified edge representation works well for the physical optics diffraction in flat and concave surfaces; errors appear especially for the observer near the reflection shadow boundary if the frequency is low for the convex scatterer. This paper gives the explicit expression of the higher-order correction for the modified edge representation.

  13. Spatio-selective surface modification of glass assisted by laser-induced deposition of gold nanoparticles

    International Nuclear Information System (INIS)

    Takahashi, Hironobu; Niidome, Yasuro; Hisanabe, Hideyuki; Kuroiwa, Keita; Kimizuka, Nobuo; Yamada, Sunao

    2006-01-01

    Using pulsed laser irradiation (532 nm), dodecanethiol-capped gold nanoparticles (DT-Au) were deposited on the laser-irradiated region of a hydrophobic glass substrate modified with dimethyloctadecylchlorosilane (DMOS). After removal of deposited DT-Au, the laser-deposited region on the substrate was hydrophilic, as verified by static water contact angles. X-ray photoelectron spectroscopy suggested that the naked glass surface was not exposed at the hydrophilic region. Immersion of the substrate into gold nanorod (NR) solution selectively immobilized NRs on the hydrophilic surface via electrostatic interactions, indicating that the hydrophilic region was an anionic surface. From these results, it is expected that some immobilized DMOS groups on the laser-irradiated region of the substrate were oxidized during DT-Au deposition and fragmentation of the deposited DT-Au

  14. Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balance

    Science.gov (United States)

    Tang, G.; Bartlein, P. J.

    2012-01-01

    Water balance models of simple structure are easier to grasp and more clearly connect cause and effect than models of complex structure. Such models are essential for studying large spatial scale land surface water balance in the context of climate and land cover change, both natural and anthropogenic. This study aims to (i) develop a large spatial scale water balance model by modifying a dynamic global vegetation model (DGVM), and (ii) test the model's performance in simulating actual evapotranspiration (ET), soil moisture and surface runoff for the coterminous United States (US). Toward these ends, we first introduced development of the "LPJ-Hydrology" (LH) model by incorporating satellite-based land covers into the Lund-Potsdam-Jena (LPJ) DGVM instead of dynamically simulating them. We then ran LH using historical (1982-2006) climate data and satellite-based land covers at 2.5 arc-min grid cells. The simulated ET, soil moisture and surface runoff were compared to existing sets of observed or simulated data for the US. The results indicated that LH captures well the variation of monthly actual ET (R2 = 0.61, p 0.46, p 0.52) with observed values over the years 1982-2006, respectively. The modeled spatial patterns of annual ET and surface runoff are in accordance with previously published data. Compared to its predecessor, LH simulates better monthly stream flow in winter and early spring by incorporating effects of solar radiation on snowmelt. Overall, this study proves the feasibility of incorporating satellite-based land-covers into a DGVM for simulating large spatial scale land surface water balance. LH developed in this study should be a useful tool for studying effects of climate and land cover change on land surface hydrology at large spatial scales.

  15. Competitive protein adsorption to polymer surface from human serum

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Larsen, Niels Bent

    2008-01-01

    Surface modification by "soft" plasma polymerisation to obtain a hydrophilic and non-fouling polymer surface has been validated using radioactive labelling. Adsorption to unmodified and modified polymer surfaces, from both single protein and human serum solutions, has been investigated. By using...... different radioisotopes, albumin and Immunoglobulin G (IgG) adsorption has been monitored simultaneously during competitive adsorption processes, which to our knowledge has not been reported in the literature before. Results show that albumin and IgG adsorption is dependent on adsorption time...... and on the presence and concentration of other proteins in bulk solutions during adsorption. Generally, lower albumin and IgG adsorption was observed on the modified and more hydrophilic polymer surfaces, but otherwise the modified and unmodified polymer surfaces showed the same adsorption characteristics....

  16. Study on the surface of fluorosilicone acrylate RGP contact lens treated by low-temperature nitrogen plasma

    International Nuclear Information System (INIS)

    Ren Li; Yin Shiheng; Zhao Lianna; Wang Yingjun; Chen Hao; Qu Jia

    2008-01-01

    In order to improve the surface hydrophilicity of fluorosilicone acrylate rigid gas permeable (RGP) contact lens, low temperature nitrogen plasma was used to modify the lens surface. Effects of plasma conditions on the surface structures and properties were investigated. Results indicated that the surface hydrophilicity of RGP contact lens was significantly improved after treatment. X-ray photoelectron spectroscopy (XPS) results showed that the nitrogen element was successfully incorporated into the surface. Furthermore, some new bonds such as N-C=O, F - and silicate were formed on the lens surface after nitrogen plasma treatment, which could result in the improvement of the surface hydrophilicity. Scanning electronic microscope (SEM) results indicated that nitrogen plasma with moderate power could make the surface smoother in some degree, while plasma with higher power could etch the surface

  17. Chemical Sensors Based on IR Spectroscopy and Surface-Modified Waveguides

    Science.gov (United States)

    Lopez, Gabriel P.; Niemczyk, Thomas

    1999-01-01

    Sol-gel processing techniques have been used to apply thin porous films to the surfaces of planar infrared (IR) waveguides to produce widely useful chemical sensors. The thin- film coating serves to diminish the concentration of water and increase the concentration of the analyte in the region probed by the evanescent IR wave. These porous films are composed of silica, and therefore, conventional silica surface modification techniques can be used to give the surface a specific functional character. The sol-gel film was surface-modified to make the film highly hydrophobic. These sensors were shown to be capable of detecting non-polar organic analytes, such as benzonitrile, in aqueous solution with detection limits in the ppb range. Further, these porous sol-gel structures allow the analytes to diffuse into and out of the films rapidly, thus reaching equilibrium in less than ten seconds. These sensors are unique because of the fact that their operation is based on the measurement of an IR absorption spectrum. Thus, these sensors are able to identify the analytes as well as measure concentration with high sensitivity. These developments have been documented in previous reports and publications. Recently, we have also targeted detection of the polar organic molecules acetone and isopropanol in aqueous solution. Polar organics are widely used in industrial and chemical processes, hence it is of interest to monitor their presence in effluents or decontamination process flows. Although large improvements in detection limits were expected with non-polar organic molecules in aqueous solutions using very hydrophobic porous sol-gel films on silicon attenuated total reflectance (Si ATR) waveguides, it was not as clear what the detection enhancements might be for polar organic molecules. This report describes the use of modified sol-gel-coated Si ATR sensors for trace detection and quantitation of small polar organic molecules in aqueous solutions. The detection of both acetone

  18. Carbon monoxide oxidation on a Au(111 surface modified by spontaneously deposited Ru

    Directory of Open Access Journals (Sweden)

    ROLF-JÜRGEN BEHM

    2001-04-01

    Full Text Available The spontaneous deposition of Ru on Au(111 was performed in 10-3 M RuCl3 + 0.5 M H2SO4 solution. The obtained surface was characterized by STM under potential control in 0.5 M H2SO4 solution. The coverage of the Au(111 terraces by deposited Ru was estimated by STM to be 0.02 ML. Step decoration could be noticed in the STM images, which indicates that the steps, as lined defects, are active sites for the nucleation of Ru monolayer islands, while the random distribution of Ru nuclei, observed on the terraces indicates point defects as active sites. The electrocatalytic activity of Au(111 surface modified by spontaneously deposited Ru was studied towards CO oxidation. The significant enhancement in the reaction rate compared to CO oxidation on a pure Au(111 surface, indicated that the edges of the deposited Ru islands were the active sites for the reaction.

  19. Directed self-assembly of nanogold using a chemically modified nanopatterned surface

    Science.gov (United States)

    Nidetz, Robert; Kim, Jinsang

    2012-02-01

    Electron-beam lithography (EBL) was used to define an aminosilane nanopatterned surface in order to electrostatically self-assemble gold nanoparticles (Au NPs). The chemically modified nanopatterned surfaces were immersed into a Au NP solution to allow the Au NPs to self-assemble. Equilibrium self-assembly was achieved in only 20 min. The number of Au NPs that self-assembled on an aminosilane dot was controlled by manipulating the diameters of both the Au NPs and the dots. Adding salt to the Au NP solution enabled the Au NPs to self-assemble in greater numbers on the same sized dot. However, the preparation of the Au NP solution containing salt was sensitive to spikes in the salt concentration. These spikes led to aggregation of the Au NPs and non-specific deposition of Au NPs on the substrate. The Au NP patterned surfaces were immersed in a sodium hydroxide solution in order to lift-off the patterned Au NPs, but no lift-off was observed without adequate physical agitation. The van der Waals forces are too strong to allow for lift-off despite the absence of electrostatic forces.

  20. Directed self-assembly of nanogold using a chemically modified nanopatterned surface

    International Nuclear Information System (INIS)

    Nidetz, Robert; Kim, Jinsang

    2012-01-01

    Electron-beam lithography (EBL) was used to define an aminosilane nanopatterned surface in order to electrostatically self-assemble gold nanoparticles (Au NPs). The chemically modified nanopatterned surfaces were immersed into a Au NP solution to allow the Au NPs to self-assemble. Equilibrium self-assembly was achieved in only 20 min. The number of Au NPs that self-assembled on an aminosilane dot was controlled by manipulating the diameters of both the Au NPs and the dots. Adding salt to the Au NP solution enabled the Au NPs to self-assemble in greater numbers on the same sized dot. However, the preparation of the Au NP solution containing salt was sensitive to spikes in the salt concentration. These spikes led to aggregation of the Au NPs and non-specific deposition of Au NPs on the substrate. The Au NP patterned surfaces were immersed in a sodium hydroxide solution in order to lift-off the patterned Au NPs, but no lift-off was observed without adequate physical agitation. The van der Waals forces are too strong to allow for lift-off despite the absence of electrostatic forces. (paper)

  1. Study on surface adhesion of Plasma modified Polytetrafluoroethylene hollow fiber membrane

    Science.gov (United States)

    Chen, Jiangrong; Zhang, Huifeng; Liu, Guochang; Guo, Chungang; Lv, Jinglie; Zhangb, Yushan

    2018-01-01

    Polytetrafluoroethylene (PTFE) is popular membrane material because of its excellent thermal stability, chemical stability and mechanical stability. However, the low surface energy and non-sticky property of PTFE present challenges for modification. In the present study, plasma treatment was performed to improve the surface adhesion of PTFE hollow fiber membrane. The effect of discharge voltage, treatment time on the adhesion of PTFE hollow fiber membrane was symmetrically evaluated. Results showed that the plasma treatment method contributed to improve the surface activity and roughness of PTFE hollow fiber membrane, and the adhesion strength depend significantly on discharge voltage, which was beneficial to seepage pressure of PTFE hollow fiber membrane module. The adhesion strength of PTFE membrane by plasma treated at 220V for 3min reached as high as 86.2 N, far surpassing the adhesion strength 12.7 N of pristine membrane. Furthermore, improvement of content of free radical and composition analysis changes of the plasma modified PTFE membrane were investigated. The seepage pressure of PTFE membrane by plasma treated at 220V for 3min was 0.375 MPa, which means that the plasma treatment is an effective technique to improve the adhesion strength of membrane.

  2. Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing time.

    Science.gov (United States)

    Yap, A U J; Ong, S B; Yap, W Y; Tan, W S; Yeo, J C

    2002-01-01

    This study compared the surface texture of resin-modified glass ionomer cements after immediate and delayed finishing with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of 64 freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (3M-ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-fluted tungsten carbide burs. The teeth were then randomly divided into four groups of 16 teeth. Half of the teeth in each group were finished immediately, while the remaining half were finished after one-week storage in distilled water at 37 degrees C. The following finishing/polishing systems were employed: (a) Robot Carbides; (b) Super-Snap system; (c) OneGloss and (d) CompoSite Polishers. The mean surface roughness (microm; n=8) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Ra values were generally lower in both vertical and horizontal axis with delayed finishing/polishing. Although significant differences in RaV and RaH values were observed among several systems with immediate finishing/polishing, only one (Fuji II LC: RaH - Super-Snap < Robot Carbides) was observed with delayed finishing.

  3. Neutral hydrophilic coatings for capillary electrophoresis prepared by controlled radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Fabián H.; Gómez, Jorge E.; Espinal, José H.; Sandoval, Junior E., E-mail: junior.sandoval@correounivalle.edu.co

    2016-12-15

    In the present study, porous silica particles as well as impervious fused-silica wafers and capillary tubes were modified with hydrophilic polymers (hydroxylated polyacrylamides and polyacrylates), using a surface-confined grafting procedure based on atom transfer radical polymerization (ATRP) which was also surface-initiated from α-bromoisobutyryl groups. Initiator immobilization was achieved by hydrosilylation of allyl alcohol on hydride silica followed by esterification of the resulting propanol-bonded surface with α-bromoisobutyryl bromide. Elemental analysis, IR and NMR spectroscopies on silica micro-particles, atomic force microscopy, ellipsometry and profilometry on fused-silica wafers, as well as CE on fused-silica tubes were used to characterize the chemically modified silica substrate at different stages. We studied the effect of monomer concentration as well as cross-linker on the ability of the polymer film to reduce electroosmosis and to prevent protein adsorption (i. e., its non-fouling capabilities) and found that the former was rather insensitive to both parameters. Surface deactivation towards adsorption was somewhat more susceptible to monomer concentration and appeared also to be favored by a low concentration of the cross-linker. The results show that hydrophilic polyacrylamide and polyacrylate coatings of controlled thickness can be prepared by ATRP under very mild polymerization conditions (aqueous solvent, room temperature and short reaction times) and that the coated capillary tubes exhibit high efficiencies for protein separations (0.3–0.6 million theoretical plates per meter) as well as long-term hydrolytic stability under the inherently harsh conditions of capillary isoelectric focusing. Additionally, there was no adsorption of lysozyme on the coated surface as indicated by a complete recovery of the basic enzyme. Furthermore, since polymerization is confined to the inner capillary surface, simple precautions (e.g., solution

  4. Modified PAMAM dendrimer with 4-carbomethoxypyrrolidone surface groups reveals negligible toxicity against three rodent cell-lines

    DEFF Research Database (Denmark)

    Janaszewska, Anna; Ciolkowski, Michal; Wróbel, Dominika

    2013-01-01

    Modification of the surface groups of dendrimers is one of the methods to improve their biocompatibility. This article presents results of experiments related to the toxicity of a modified polyamidoamine (PAMAM) dendrimer of the fourth generation with 4-carbomethoxypyrrolidone surface groups (PAM...

  5. A modified Poisson-Boltzmann surface excess calculation with a field dependent dielectric constant

    International Nuclear Information System (INIS)

    Gordillo, G.J.; Molina, F.V.; Posadas, D.

    1990-01-01

    The Unequal Radius Modified Gouy-Chapman (URMGC) was applied to mixtures of electrolytes. It was considered that the two anions, (1) and (2), have different radius, r 1 and r 2 , being r 2 smaller than r 1 . The dielectric constant was taken as a function of the electric field, using the theoretical Booth equation, or as a linear dependence varying between 6 and 78 when r 2 1 . The results show that the surface excess of anion 2 is much greater than the one predicted by Gouy-Chapman theory when the proportion of 2 increases in the mixture, while both the other anion and the cation show negative deviation. This effect is more evident in mixtures than in the case of single electrolytes, and has a maximum for a composition that depends on the chosen parameters for the model. (Author) [es

  6. Path Loss Prediction Over the Lunar Surface Utilizing a Modified Longley-Rice Irregular Terrain Model

    Science.gov (United States)

    Foore, Larry; Ida, Nathan

    2007-01-01

    This study introduces the use of a modified Longley-Rice irregular terrain model and digital elevation data representative of an analogue lunar site for the prediction of RF path loss over the lunar surface. The results are validated by theoretical models and past Apollo studies. The model is used to approximate the path loss deviation from theoretical attenuation over a reflecting sphere. Analysis of the simulation results provides statistics on the fade depths for frequencies of interest, and correspondingly a method for determining the maximum range of communications for various coverage confidence intervals. Communication system engineers and mission planners are provided a link margin and path loss policy for communication frequencies of interest.

  7. Metal Recovery and Preconcentration by Edta and Dtpa Modified Silica Surfaces

    Directory of Open Access Journals (Sweden)

    Eveliina Repo

    2017-03-01

    Full Text Available This study focuses on the adsorption and preconcentration of various metals by silica gel surfaces modified with aminopolycarboxylic acids namely ethylenediaminetetraacetic acid or diethylenetriamine-pentaacetic acid. The adsorption performance of the studied materials was determined in mixed metal solutions and the adsorption isotherm studies were conducted for cobalt, nickel, cadmium, and lead. The results were modeled using various theoretical isotherm equations, which suggested that two different adsorption sites were involved in metal removal although lead showed clearly different adsorption behavior attributed to its lowest hydration tendency. Efficient regeneration of the adsorbents and preconcentration of metals was conducted with nitric acid. Results indicated that the metals under study could be analyzed rather accurately after preconcentration from both pure, saline and ground water samples.

  8. Combined slurry and cavitation erosion resistance of surface modified SS410 stainless steel

    Science.gov (United States)

    Amarendra, H. J.; Pratap, M. S.; Karthik, S.; Punitha Kumara, M. S.; Rajath, H. C.; Ranjith, H.; Shubhatunga, S. V.

    2018-03-01

    Slurry erosion and combined slurry and cavitation erosion resistance of thermal spray coatings are studied and compared with the as-received martensitic stainless steel material. 70Ni-Cr coatings are deposited on SS 410 material through plasma thermal spray process. The synergy effect of the combined slurry and cavitation erosion resistance of plasma thermal spray coatings were investigated in a slurry pot tester in the presence of bluff bodies known as Cavitation Inducers. Results showed the combined slurry and cavitation erosion resistance of martensitic stainless steel - 410 can be improved by plasma thermal spray coating. It is observed that the plasma spray coated specimens are better erosion resistant than the as- received material, subjected to erosion test under similar conditions. As-received and the surface modified steels are mechanically characterized for its hardness, bending. Morphological studies are conducted through scanning electron microscope.

  9. Optimization of Nanocomposite Modified Asphalt Mixtures Fatigue Life using Response Surface Methodology

    Science.gov (United States)

    Bala, N.; Napiah, M.; Kamaruddin, I.; Danlami, N.

    2018-04-01

    In this study, modelling and optimization of materials polyethylene, polypropylene and nanosilica for nanocomposite modified asphalt mixtures has been examined to obtain optimum quantities for higher fatique life. Response Surface Methodology (RSM) was applied for the optimization based on Box Behnken design (BBD). Interaction effects of independent variables polymers and nanosilica on fatique life were evaluated. The result indicates that the individual effects of polymers and nanosilica content are both important. However, the content of nanosilica used has more significant effect on fatique life resistance. Also, the mean error obtained from optimization results is less than 5% for all the responses, this indicates that predicted values are in agreement with experimental results. Furthermore, it was concluded that asphalt mixture design with high performance properties, optimization using RSM is a very effective approach.

  10. The surface characteristics of hyperbranched polyamide modified corncob and its adsorption property for Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hai, E-mail: linhai@ces.ustb.edu.cn [School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants, Beijing 100083 (China); Han, Shaoke; Dong, Yingbo; He, Yinhai [School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants, Beijing 100083 (China)

    2017-08-01

    Highlights: • An anion adsorbent was synthesized by hyperbranched polyamide modified corncob (HPMC). • The surface characteristics of samples (RCC, HPMC, HPMC-Cr) were studied. • Langmuir isotherm provided more fit and maximum adsorption capacity was 131.6 mg/g. • The adsorption process was chemisorption, controlled by intra-particle diffusion and film diffusion. • Adsorption is fast, stable, spontaneous and endothermic. - Abstract: A low-cost anion adsorbent for Cr(VI) effectively removing was synthesized by hyperbranched polyamide modified corncob (HPMC). Samples were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy, Fourier transform infrared (FTIR) and zeta potential analysis. Kinetics, isotherms and thermodynamics studies of HPMC for Cr(VI) adsorption were investigated in batch static experiments, in the temperature range of 25–45 °C, pH = 2.0. Results showed that the adsorption was rapid and stable, with the uptake capacity higher than 80% after 30 min. Adsorption behavior and rate-controlling mechanisms were analyzed using three kinetic models (pseudo-first order, pseudo-second order, intra-particle kinetic model). Kinetic studies showed that the adsorption of HPMC to Cr(VI) relied the pseudo-second-order model, and controlled both by the intra-particle diffusion and film diffusion. Equilibrium data was tested by Langmuir and Freundlich adsorption isotherm models. Langmuir model was more suitable to indicate a homogeneous distribution of active sites on HPMC and monolayer adsorption. The maximum adsorption capacity from the Langmuir model, q{sub max}, was 131.6 mg/g at pH 2.0 and 45 °C for HPMC. Thermodynamic parameters revealed spontaneous and endothermic nature of the Cr(VI) adsorption onto HPMC.

  11. Surface modified natural zeolite as a carrier for sustained diclofenac release: A preliminary feasibility study.

    Science.gov (United States)

    de Gennaro, Bruno; Catalanotti, Lilia; Cappelletti, Piergiulio; Langella, Alessio; Mercurio, Mariano; Serri, Carla; Biondi, Marco; Mayol, Laura

    2015-06-01

    In view of zeolite potentiality as a carrier for sustained drug release, a clinoptilolite-rich rock from California (CLI_CA) was superficially modified with cetylpyridinium chloride and loaded with diclofenac sodium (DS). The obtained surface modified natural zeolites (SMNZ) were characterized by confocal scanning laser microscopy (CLSM), powder X-ray diffraction (XRPD) and laser light scattering (LS). Their flowability properties, drug adsorption and in vitro release kinetics in simulated intestinal fluid (SIF) were also investigated. CLI_CA is a Na- and K-rich clinoptilolite with a cationic exchange ability that fits well with its zeolite content (clinoptilolite=80 wt%); the external cationic exchange capacity is independent of the cationic surfactant used. LS and CLSM analyses have shown a wide distribution of volume diameters of SMNZ particles that, along with their irregular shape, make them cohesive with scarce flow properties. CLSM observation has revealed the localization of different molecules in/on SMNZ by virtue of their chemical nature. In particular, cationic and polar probes prevalently localize in SMNZ bulk, whereas anionic probes preferentially arrange themselves on SMNZ surface and the loading of a nonpolar molecule in/on SMNZ is discouraged. The adsorption rate of DS onto SMNZ was shown by different kinetic models highlighting the fact that DS adsorption is a pseudo-second order reaction and that the diffusion through the boundary layer is the rate-controlling step of the process. DS release in an ionic medium, such as SIF, can be sustained for about 5h through a mechanism prevalently governed by anionic exchange with a rapid final phase. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Influence of spacer length on heparin coupling efficiency and fibrinogen adsorption of modified titanium surfaces

    Directory of Open Access Journals (Sweden)

    Gbureck Uwe

    2007-07-01

    Full Text Available Abstract Background Chemical bonding of the drug onto surfaces by means of spacer molecules is accompanied with a reduction of the biological activity of the drug due to a constricted mobility since normally only short spacer molecule like aminopropyltrimethoxysilane (APMS are used for drug coupling. This work aimed to study covalent attachment of heparin to titanium(oxide surfaces by varying the length of the silane coupling agent, which should affect the biological potency of the drug due to a higher mobility with longer spacer chains. Methods Covalent attachment of heparin to titanium metal and TiO2 powder was carried out using the coupling agents 3-(Trimethoxysilyl-propylamine (APMS, N- [3-(Trimethoxysilylpropyl]ethylenediamine (Diamino-APMS and N1- [3-(Trimethoxy-silyl-propyl]diethylenetriamine (Triamino-APMS. The amount of bound coupling agent and heparin was quantified photometrically by the ninhydrin reaction and the tolidine-blue test. The biological potency of heparin was determined photometrically by the chromogenic substrate Chromozym TH and fibrinogen adsorption to the modified surfaces was researched using the QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring technique. Results Zeta-potential measurements confirmed the successful coupling reaction; the potential of the unmodified anatase surface (approx. -26 mV shifted into the positive range (> + 40 mV after silanisation. Binding of heparin results in a strongly negatively charged surface with zeta-potentials of approx. -39 mV. The retaining biological activity of heparin was highest for the spacer molecule Triamino-APMS. QCM-D measurements showed a lower viscosity for adsorbed fibrinogen films on heparinised surfaces by means of Triamino-APMS. Conclusion The remaining activity of heparin was found to be highest for the covalent attachment with Triamino-APMS as coupling agent due to the long chain of this spacer molecule and therefore the highest mobility of the drug

  13. Surface chemical and biological characterization of flax fabrics modified with silver nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Paladini, F.; Picca, R.A.; Sportelli, M.C.; Cioffi, N.; Sannino, A.; Pollini, M.

    2015-01-01

    Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag 2 O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. - Highlights: • Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications. • Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution. • Flax fabrics were characterized from a biological and surface chemical point of view. • Scaling up of the process was confirmed

  14. Role of surface chemistry in modified ACF (activated carbon fiber)-catalyzed peroxymonosulfate oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shiying, E-mail: ysy@ouc.edu.cn [Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100 (China); College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (MEGE), Qingdao 266100 (China); Li, Lei [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); Xiao, Tuo [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); China City Environment Protection Engineering Limited Company, Wuhan 430071 (China); Zheng, Di; Zhang, Yitao [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China)

    2016-10-15

    Highlights: • ACF can efficiently activate peroxymonosulfate to degrade organic pollutants. • Basic functional groups may mainly increase the adsorption capacity of ACF. • C1, N1, N2 have promoting effect on the ACF catalyzed PMS oxidation. • Modification by heat after nitric acid is also a way of ACF regeneration. - Abstract: A commercial activated carbon fiber (ACF-0) was modified by three different methods: nitration treatment (ACF-N), heat treatment (ACF-H) and heat treatment after nitration (ACF-NH), and the effects of textural and chemical properties on the ability of the metal-free ACF-catalyzed peroxymonosulfate (PMS) oxidation of Reactive Black 5 (RB5), an azo dye being difficultly adsorbed onto ACF, in aqueous solution were investigated in this work. Surface density of functional groups, surface area changes, surface morphology and the chemical state inside ACF samples were characterized by Boehm titration, N{sub 2} adsorption, scanning electron microscopy in couple with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), respectively. XPS spectra deconvolution was applied to figure out the importance of surface nitrogen-containing function groups. We found that π-π, pyridine and amine have promoting effect on the catalytic oxidation while the −NO{sub 2} has inhibitory effect on the ACF/PMS systems for RB5 destroy. Sustainability and renewability of the typical ACF-NH for catalytic oxidation of RB5 were also discussed in detail. Information about our conclusions are useful to control and improve the performance of ACF-catalyzed PMS oxidation for organic pollutants in wastewater treatment.

  15. Oxidized template-synthesized mesoporous carbon with pH-dependent adsorption activity: A promising adsorbent for removal of hydrophilic ionic liquid

    Science.gov (United States)

    Zhang, Ling; Cao, Wugang; Alvarez, Pedro J. J.; Qu, Xiaolei; Fu, Heyun; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2018-05-01

    Aiming to remove ionic liquid pollutants from water, an ordered mesoporous carbon CMK-3 (OMC) was prepared and modified by oxidation with nitric acid. A commercial microporous activated carbon adsorbent, Filtrasorb-300 (AC), was used as benchmark. Boehm titration showed that oxidized OMC had a substantially higher oxygen content than oxidized AC. Adsorption of the hydrophilic imidazolium-based ionic liquid 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) on OMC and AC was well-described by the Freundlich isotherm model. Surface oxidation markedly enhanced [Bmim]Cl adsorption by both OMC and AC. Nevertheless, [Bmim]Cl adsorption was much higher on oxidized OMC than on oxidized AC. Increasing pH had negligible influence on [Bmim]Cl adsorption on pristine OMC, but enhanced adsorption on oxidized OMC. Regeneration tests showed stable performance of oxidized OMC over five adsorption-desorption cycles. Thus, oxidized OMC can be a highly effective adsorbent for the removal of hydrophilic ionic liquids from water.

  16. Improvement of epoxy resin properties by incorporation of TiO2 nanoparticles surface modified with gallic acid esters

    International Nuclear Information System (INIS)

    Radoman, Tijana S.; Džunuzović, Jasna V.; Jeremić, Katarina B.; Grgur, Branimir N.; Miličević, Dejan S.; Popović, Ivanka G.; Džunuzović, Enis S.

    2014-01-01

    Highlights: • Nanocomposites of epoxy resin and TiO 2 nanoparticles surface modified with gallates. • The T g of epoxy resin was increased by incorporation of surface modified TiO 2 . • WVTR of epoxy resin decreased in the presence of surface modified TiO 2 nanoparticles. • WVTR of nanocomposites was reduced with increasing gallates hydrophobic chain length. • Modified TiO 2 nanoparticles react as oxygen scavengers, inhibiting steel corrosion. - Abstract: Epoxy resin/titanium dioxide (epoxy/TiO 2 ) nanocomposites were obtained by incorporation of TiO 2 nanoparticles surface modified with gallic acid esters in epoxy resin. TiO 2 nanoparticles were obtained by acid catalyzed hydrolysis of titanium isopropoxide and their structural characterization was performed by X-ray diffraction and transmission electron microscopy. Three gallic acid esters, having different hydrophobic part, were used for surface modification of the synthesized TiO 2 nanoparticles: propyl, hexyl and lauryl gallate. The gallate chemisorption onto surface of TiO 2 nanoparticles was confirmed by Fourier transform infrared and ultraviolet–visible spectroscopy, while the amount of surface-bonded gallates was determined using thermogravimetric analysis. The influence of the surface modified TiO 2 nanoparticles, as well as the length of hydrophobic part of the gallate used for surface modification of TiO 2 nanoparticles, on glass transition temperature, barrier, dielectric and anticorrosive properties of epoxy resin was investigated by differential scanning calorimetry, water vapor transmission test, dielectric spectroscopy, electrochemical impedance spectroscopy and polarization measurements. Incorporation of surface modified TiO 2 nanoparticles in epoxy resin caused increase of glass transition temperature and decrease of the water vapor permeability of epoxy resin. The water vapor transmission rate of epoxy/TiO 2 nanocomposites was reduced with increasing hydrophobic part chain length of

  17. Polyethylene/hydrophilic polymer blends for biomedical applications.

    Science.gov (United States)

    Brynda, E; Houska, M; Novikova, S P; Dobrova, N B

    1987-01-01

    Polyethylene blends with poly(2-hydroxyethyl methacrylate) [poly(HEMA)] or poly(2,3-dihydroxypropyl methacrylate) [poly(DHPMA)] were prepared by swelling polyethylene with HEMA or 2,3-epoxypropyl methacrylate (EPMA) and by polymerization of the respective monomers. Poly(EPMA) in blends was hydrolysed to poly(DHPMA) with acetic acid. The blends had similar surface and bulk compositions. Swelling with water and surface wettability were proportional to the content of the hydrophilic component; at the same content the polyethylene/poly(DHPMA) blends appeared more hydrophilic than those of polyethylene/poly(HEMA). Thrombus formation in contact with blood examined ex vivo and in vivo was considerably slower on the blends than on unmodified polyethylene. The tests indicated optima in composition; the best biological response was achieved with the blends containing about 14% poly(HEMA) or 16% poly(DHPMA).

  18. Growth and Functionality of Cells Cultured on Conducting and Semi-Conducting Surfaces Modified with Self-Assembled Monolayers (SAMs

    Directory of Open Access Journals (Sweden)

    Rajendra K. Aithal

    2016-02-01

    Full Text Available Bioengineering of dermal and epidermal cells on surface modified substrates is an active area of research. The cytotoxicity, maintenance of cell phenotype and long-term functionality of human dermal fibroblast (HDF cells on conducting indium tin oxide (ITO and semi-conducting, silicon (Si and gallium arsenide (GaAs, surfaces modified with self-assembled monolayers (SAMs containing amino (–NH2 and methyl (–CH3 end groups have been investigated. Contact angle measurements and infrared spectroscopic studies show that the monolayers are conformal and preserve their functional end groups. Morphological analyses indicate that HDFs grow well on all substrates except GaAs, exhibiting their normal spindle-shaped morphology and exhibit no visible signs of stress or cytoplasmic vacuolation. Cell viability analyses indicate little cell death after one week in culture on all substrates except GaAs, where cells died within 6 h. Cells on all surfaces proliferate except on GaAs and GaAs-ODT. Cell growth is observed to be greater on SAM modified ITO and Si-substrates. Preservation of cellular phenotype assessed through type I collagen immunostaining and positive staining of HDF cells were observed on all modified surfaces except that on GaAs. These results suggest that conducting and semi-conducting SAM-modified surfaces support HDF growth and functionality and represent a promising area of bioengineering research.

  19. Polysiloxane surface modified with bipyrazolic tripodal receptor for quantitative lead adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Radi, Smaail, E-mail: radi_smaail@yahoo.fr [Laboratoire de Chimie Organique, Macromoleculaire et Produits Naturels, Equipe de Chimie Bio-organique et Macromoleculaire, Unite Associee au CNRST URAC 25, Departement de Chimie, Faculte des Sciences, Universite Med I, BP 524, 60 000 Oujda (Morocco); Tighadouini, Said; Toubi, Yahya [Laboratoire de Chimie Organique, Macromoleculaire et Produits Naturels, Equipe de Chimie Bio-organique et Macromoleculaire, Unite Associee au CNRST URAC 25, Departement de Chimie, Faculte des Sciences, Universite Med I, BP 524, 60 000 Oujda (Morocco); Bacquet, Maryse [Universite des Sciences et Technologies de Lille, UMET: Unite Materiaux et Transformations UMR8207, Equipe Ingenierie des Systemes Polymeres, Batiment C6 salle 119-59655 Villeneuve d' Ascq (France)

    2011-01-15

    A new silica gel compound modified N,N-bis(3,5-dimethylpyrazol-1-ylmethyl) amine (SiN{sub 2}Pz) was synthesized and characterized by elemental analysis, FT-IR, {sup 13}C NMR of the solid state, nitrogen adsorption-desorption isotherm, BET surface area and BJH pore sizes. The new surface exhibits good chemical and thermal stability determined by thermogravimetry curves (TGA). The effect of pH and stirring time on the adsorption of Pb(II) were studied. The process of metal retention was followed by batch method and the optimum pH value for the quantitative adsorption of this toxic metal ion was 7. At this pH value, the new functionalized polysiloxane presents further improvements and shows higher affinity (123 mg of Pb{sup 2+}/g of silica) for the effective adsorption of Pb(II) compared to others described sorbents. The extracted amounts of Pb(II) were determined by atomic absorption measurements.

  20. Surface modified zeolite-based granulates for the sustained release of diclofenac sodium.

    Science.gov (United States)

    Serri, Carla; de Gennaro, Bruno; Quagliariello, Vincenzo; Iaffaioli, Rosario Vincenzo; De Rosa, Giuseppe; Catalanotti, Lilia; Biondi, Marco; Mayol, Laura

    2017-03-01

    In this study, a granulate for the oral controlled delivery of diclofenac sodium (DS), an anionic sparingly soluble nonsteroidal anti-inflammatory drug, has been realized by wet granulation, using a surface modified natural zeolite (SMNZ) as an excipient. The surface modification of the zeolite has been achieved by means of a cationic surfactant, so as to allow the loading of DS through ionic interaction and bestow a control over the drug release mechanism. The granules possessed a satisfactory dosage uniformity, a flowability suitable for an oral dosage form manufacturing, along with a sustained drug release up to 9h, driven by both ion exchange and transport kinetics. Furthermore, the obtained granulate did not elicit a significant cytotoxicity and could also induce a prolonged anti-inflammatory effect on RAW264.7 cells. Taking also into account that natural zeolites are generally abundant and economic, SMNZ can be considered as an attracting alternative excipient for the production of granules with sustained release features. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Comparative of fibroblast and osteoblast cells adhesion on surface modified nanofibrous substrates based on polycaprolactone.

    Science.gov (United States)

    Sharifi, Fereshteh; Irani, Shiva; Zandi, Mojgan; Soleimani, Masoud; Atyabi, Seyed Mohammad

    2016-12-01

    One of the determinant factors for successful bioengineering is to achieve appropriate nano-topography and three-dimensional substrate. In this research, polycaprolactone (PCL) nano-fibrous mat with different roughness modified with O 2 plasma was fabricated via electrospinning. The purpose of this study was to evaluate the effect of plasma modification along with surface nano-topography of mats on the quality of human fibroblast (HDFs) and osteoblast cells (OSTs)-substrate interaction. Surface properties were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle, Fourier-transformation infrared spectroscopy. We evaluated mechanical properties of fabricated mats by tensile test. The viability and proliferation of HDFs and OSTs on the substrates were followed by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT). Mineralization of the substrate was determined by alizarin red staining method and calcium content of OSTs was determined by calcium content kit. Cells morphology was studied by SEM analysis. The results revealed that the plasma-treated electrospun nano-fibrous substrate with higher roughness was an excellent designed substrate. A bioactive topography for stimulating proliferation of HDFs and OSTs is to accelerate the latter's differentiation time. Therefore, the PCL substrate with high density and major nano-topography were considered as a bio-functional and elegant bio-substrate for tissue regeneration applications.

  2. Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst

    Directory of Open Access Journals (Sweden)

    BILJANA M. BABIĆ

    2007-08-01

    Full Text Available A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst support for Pt nano-particles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (SBET > 400 m2 g-1 and large mesoporous volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV experiments at various scan rates (from 2 to 200 mV s-1 were performed in 0.5 mol dm-3 HClO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by 1/C vs. ν0.5 extrapolation method was found to be 386 F g-1. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction.

  3. Investigation of antibacterial and wettability behaviours of plasma-modified PMMA films for application in ophthalmology

    International Nuclear Information System (INIS)

    Rezaei, Fatemeh; Abbasi-Firouzjah, Marzieh; Shokri, Babak

    2014-01-01

    The main objective of this research is the experimental investigation of the surface properties of polymethyl methacrylate (PMMA) such as wettability and the roughness effect on Escherichia coli (gram negative) cell adhesion. Radio frequency (RF; 13.56 MHz) oxygen plasma was used to enhance the antibacterial and wettability properties of this polymer for biomedical applications, especially ophthalmology. The surface was activated by O 2 plasma to produce hydrophilic functional groups. Samples were treated with various RF powers from 10 to 80 W and different gas flow rates from 20 to 120 sccm. Optical emission spectroscopy was used to monitor the plasma process. The modified surface hydrophilicity, morphology and transparency characteristics were studied by water contact angle measurements, atomic force microscopy and UV–vis spectroscopy, respectively. Based on the contact angle measurements of three liquids, surface free energy variations were investigated. Moreover, the antibacterial properties were evaluated utilizing the method of plate counting of Escherichia coli. Also, in order to investigate stability of the plasma treatment, an ageing study was carried out by water contact angle measurements repeated in the days after the treatment. For biomedical applications, especially eye lenses, highly efficient antibacterial surfaces with appropriate hydrophilicity and transparency are of great importance. In this study, it is shown that the plasma process is a reliable and convenient method to achieve these purposes. A significant alteration in the hydrophilicity of a pristine PMMA surface was observed after treatment. Also, our results indicated that the plasma-modified PMMAs exhibit appropriate antibacterial performance. Moreover, surface hydrophilicity and surface charge have more influence on bacterial adhesion rate than surface roughness. UV–vis analysis results do not show a considerable difference for transparency of samples after plasma treatment

  4. Investigation of Electrochemical Behaviour of Quercetin on the Modified Electrode Surfaces with Procaine and Aminophenyl in Non-Aquous Medium

    Directory of Open Access Journals (Sweden)

    Ibrahim Ender Mulazimoglu

    2008-01-01

    Full Text Available In this study, cyclic voltammetry and electrochemical ımpedance spectroscopy have been used to investigate the electrochemical behaviour of quercetin (3,3′,4′,5,7-pentahydroxyflavone on the procaine and aminophenyl modified electrode. The modification of procaine and aminophenyl binded electrode surface with quercetin was performed in +0,3/+2,8 V (for procaine and +0,4/+1,5 V (for aminophenyl potential range using 100 mV s-1 scanning rate having 10 cycle. A solution of 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile was used as a non-aquous solvent. For the modification process a solution of 1 mM quercetin in 0.1 M tetrabutylammonium tetrafluoroborate was used. In order to obtain these two surface, a solution of 1 mM procaine and 1 mM nitrophenyl diazonium salt in 0.1 M tetrabutylammonium tetrafluoroborate was used. By using these solutions bare glassy carbon electrode surface was modified. Nitrophenyl was reduced to amine group in 0.1 M HCl medium on the nitrophenyl modified glassy carbon elelctrode surface. Procaine modified glassy carbon electrode surface was quite electroactive. Although nitrophenyl modified glassy carbon elelctrode surface was electroinactive, it was activated by reducing nitro group into amine group. For the characterization of the modified surface 1 mM ferrocene in 0.1 M tetrabutylammonium tetrafluoroborate for cyclic voltammetry and 1 mM ferricyanide/ferrocyanide (1:1 mixture in 0,1 M KCl for electrochemical impedance spectroscopy were used.

  5. Controlling hydrophilicity of polymer film by altering gas flow rate in atmospheric-pressure homogeneous plasma

    International Nuclear Information System (INIS)

    Kang, Woo Seok; Hur, Min; Lee, Jae-Ok; Song, Young-Hoon

    2014-01-01

    Graphical abstract: - Highlights: • Controlling hydrophilicity of polymer film by varying gas flow rate is proposed in atmospheric-pressure homogeneous plasma treatment. • Without employing additional reactive gas, requiring more plasma power and longer treatment time, hydrophilicity of polyimide films was improved after the low-gas-flow plasma treatment. • The gas flow rate affects the hydrophilic properties of polymer surface by changing the discharge atmosphere in the particular geometry of the reactor developed. • Low-gas-flow induced wettability control suggests effective and economical plasma treatment. - Abstract: This paper reports on controlling the hydrophilicity of polyimide films using atmospheric-pressure homogeneous plasmas by changing only the gas flow rate. The gas flow changed the discharge atmosphere by mixing the feed gas with ambient air because of the particular geometry of the reactor developed for the study, and a low gas flow rate was found to be favorable because it generated abundant nitrogen or oxygen species that served as sources of hydrophilic functional groups over the polymer surface. After low-gas-flow plasma treatment, the polymer surface exhibited hydrophilic characteristics with increased surface roughness and enhanced chemical properties owing to the surface addition of functional groups. Without adding any reactive gases or requiring high plasma power and longer treatment time, the developed reactor with low-gas-flow operation offered effective and economical wettability control of polyimide films

  6. Design and investigation of photo-induced super-hydrophilic materials for car mirrors

    International Nuclear Information System (INIS)

    Eiamchai, Pitak; Chindaudom, Pongpan; Horprathum, Mati; Patthanasettakul, Viyapol; Limsuwan, Pichet

    2009-01-01

    During the past decades, interests in various properties in titanium dioxide thin films have been growing rapidly. There have been several reports for TiO 2 thin films prepared on various media with photocatalytic and hydrophilic properties, in order to function as self-cleaning and/or anti-fogging materials. An obvious application is usually found in side-view car mirrors in the automobile industries. In this study, a number of photocatalytic TiO 2 films are prepared on soda-lime glasses for car mirrors by an electron-beam evaporation. The designs and development of the photocatalytic TiO 2 films, based on crystallinity, deposition rate, film thickness, film structure, and surface roughness are discussed. In comparison to the commercialized products, a systematic investigation procedure for the super-hydrophilic properties of the light-induced TiO 2 films for car mirrors has been developed, based on super-hydrophilicity, sustainability, self-cleaning property, and degradation of the samples. In addition, physical characterization by X-ray diffraction and surface roughness are also discussed. It has been found that most commercial products attain super-hydrophilicity only after exposed to ultraviolet and solar irradiation in less than 1 h. They can also maintain hydrophilicity after rigorous cleaning process. On the other hand, our prepared TiO 2 thin films demonstrate super-hydrophilic and photocatalytic properties after exposed to ultraviolet light for more than 2 h. According to the study, their anatase crystallinity, small grain size, and surface conditions all contributes to the excellent results. However, the prepared samples do not attain sufficient retention property to maintain their hydrophilicity. Conclusively, the designs of the TiO 2 films on car mirrors prove adequate to produce super-hydrophilic materials, which still degrade over normal usage. Nevertheless, our proposed investigation methods prove useful in quality evaluation in order to

  7. Adsorption of ibuprofen from aqueous solution on chemically surface-modified activated carbon cloths

    Directory of Open Access Journals (Sweden)

    Hanen Guedidi

    2017-05-01

    Full Text Available This study aims to investigate the performance of an activated carbon cloth for adsorption of ibuprofen. The cloth was oxidized by a NaOCl solution (0.13 mol L−1 or thermally treated under N2 (700 °C for 1 hour. The raw and modified cloths were characterized by N2 adsorption–desorption measurement at 77 K, CO2 adsorption at 273 K, Boehm titrations, pHPZC measurements, X-ray Photoelectron Spectroscopy analysis, and by infrared spectroscopy. The NaOCl treatment increases the acidic sites, mostly creating phenolic and carboxylic groups and decreases both the specific surface area and slightly the micropore volume. However, the thermal treatment at 700 °C under N2 induced a slight increase in the BET specific surface area and yielded to the only increase in the carbonyl group content. Ibuprofen adsorption studies of kinetics and isotherms were carried out at pH = 3 and 7. The adsorption properties were correlated to the cloth porous textures, surface chemistry and pH conditions. The isotherms of adsorption were better reproduced by Langmuir–Freundlich models at 298, 313 and 328 K. The adsorption of ibuprofen on the studied activated carbon cloths at pH 3 was an endothermic process. The pore size distributions of all studied ibuprofen-loaded fabrics were determined by DFT method to investigate the accessible porosity of the adsorbate. Both treatments do not influence the kind of micropores where the adsorption of ibuprofen occurred.

  8. Speciation of uranium in surface-modified, hydrothermally treated, (UO2)2+-exchanged smectite clays

    International Nuclear Information System (INIS)

    Giaquinta, D.M.; Soderholm, L.; Yuchs, S.E.; Wasserman, S.R.

    1997-01-01

    A successful solution to the problem of disposal and permanent storage of water soluble radioactive species must address two issues: exclusion of the radionuclides from the environment and the prevention of leaching from the storage media into the environment. Immobilization of radionuclides in clay minerals has been studied. In addition to the use of clays as potential waste forms, information about the interactions of radionuclides with clays and how such interactions affect their speciations is crucial for successful modeling of actinide-migration. X-ray absorption spectroscopy (XAS) is used to determine the uranium speciation in exchanged and surface-modified clays. The XAS data from uranyl-loaded bentonite clay are compared with those obtained after the particle surfaces have been coated with alkylsilanes. These silane films, which render the surface of the clay hydrophobic, are added in order to minimize the ability of external water to exchange with the water in the clay interlayer, thereby decreasing the release rate of the exchanged-uranium species. Mild hydrothermal conditions are used in an effort to mimic potential geologic conditions that may occur during long-term radioactive waste storage. The XAS spectra indicate that the uranyl monomer species remain unchanged in most samples, except in those samples that were both coated with an alkylsilane and hydrothermally treated. When the clay was coated with an organic film, formed by the acidic deposition of octadecyltrimethoxysilane, hydrothermal treatment results in the formation of aggregated uranium species in which the uranium is reduced from U VI to U IV

  9. Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing systems.

    Science.gov (United States)

    Yap, Adrian U J; Tan, W S; Yeo, J C; Yap, W Y; Ong, S B

    2002-01-01

    This study investigated the surface texture of two resin-modified glass ionomer cements (RMGICs) in the vertical and horizontal axis after treatment with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-flute tungsten carbide burs. The teeth were then randomly divided into four groups and finished/polished with (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Points (CS). The sample size for each material-finishing/polishing system combination was eight. The mean surface roughness (microm) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Mean RaV ranged from 0.59-1.31 and 0.83-1.52, while mean RaH ranged from 0.80-1.43 and 0.85-1.58 for Fuji II LC and Photac-Fil, respectively. Results of statistical analysis were as follows: Fuji II LC: RaV-RC, SS

  10. Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems

    Science.gov (United States)

    Omar, Omar; Simonsson, Hanna; Palmquist, Anders; Thomsen, Peter

    2016-01-01

    Osseointegrated implants inserted in the temporal bone are a vital component of bone-anchored hearing systems (BAHS). Despite low implant failure levels, early loading protocols and simplified procedures necessitate the application of implants which promote bone formation, bone bonding and biomechanical stability. Here, screw-shaped, commercially pure titanium implants were selectively laser ablated within the thread valley using an Nd:YAG laser to produce a microtopography with a superimposed nanotexture and a thickened surface oxide layer. State-of-the-art machined implants served as controls. After eight weeks’ implantation in rabbit tibiae, resonance frequency analysis (RFA) values increased from insertion to retrieval for both implant types, while removal torque (RTQ) measurements showed 153% higher biomechanical anchorage of the laser-modified implants. Comparably high bone area (BA) and bone-implant contact (BIC) were recorded for both implant types but with distinctly different failure patterns following biomechanical testing. Fracture lines appeared within the bone ~30–50 μm from the laser-modified surface, while separation occurred at the bone-implant interface for the machined surface. Strong correlations were found between RTQ and BIC and between RFA at retrieval and BA. In the endosteal threads, where all the bone had formed de novo, the extracellular matrix composition, the mineralised bone area and osteocyte densities were comparable for the two types of implant. Using resin cast etching, osteocyte canaliculi were observed directly approaching the laser-modified implant surface. Transmission electron microscopy showed canaliculi in close proximity to the laser-modified surface, in addition to a highly ordered arrangement of collagen fibrils aligned parallel to the implant surface contour. It is concluded that the physico-chemical surface properties of laser-modified surfaces (thicker oxide, micro- and nanoscale texture) promote bone bonding

  11. Nanocomposite fibers and film containing polyolefin and surface-modified carbon nanotubes

    Science.gov (United States)

    Chu,Benjamin; Hsiao, Benjamin S.

    2010-01-26

    Methods for modifying carbon nanotubes with organic compounds are disclosed. The modified carbon nanotubes have enhanced compatibility with polyolefins. Nanocomposites of the organo-modified carbon nanotubes and polyolefins can be used to produce both fibers and films having enhanced mechanical and electrical properties, especially the elongation-to-break ratio and the toughness of the fibers and/or films.

  12. Facile and scalable preparation of highly wear-resistance superhydrophobic surface on wood substrates using silica nanoparticles modified by VTES

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Shanshan; Liu, Ming [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Wu, Yiqiang, E-mail: wuyq0506@126.com [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Hunan Provincial Collaborative Innovation Center for High-efficiency Utilization of Wood and Bamboo Resources, Central South University of Forestry and Technology, Changsha 410004 (China); Luo, Sha [College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Qing, Yan,