WorldWideScience

Sample records for particles surface modification

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

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

    2009-01-01

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

  2. Superhydrophobic surfaces fabricated by surface modification of alumina particles

    Science.gov (United States)

    Richard, Edna; Aruna, S. T.; Basu, Bharathibai J.

    2012-10-01

    The fabrication of superhydrophobic surfaces has attracted intense interest because of their widespread potential applications in various industrial fields. Recently, some attempts have been carried out to prepare superhydrophobic surfaces using metal oxide nanoparticles. In the present work, superhydrophobic surfaces were fabricated with low surface energy material on alumina particles with different sizes. It was found that particle size of alumina is an important factor in achieving stable superhydrophobic surface. It was possible to obtain alumina surface with water contact angle (WCA) of 156° and a sliding angle of Superhydrophobicity of the modified alumina is attributed to the combined effect of the micro-nanostructure and low surface energy of fatty acid on the surface. The surface morphology of the alumina powder and coatings was determined by FESEM. The stability of the coatings was assessed by conducting water immersion test. Effect of heat treatment on WCA of the coating was also studied. The transition of alumina from hydrophilic to superhydrophobic state was explained using Wenzel and Cassie models. The method is shown to have potential application for creating superhydrophobic surface on cotton fabrics.

  3. Charged particle modification of surfaces in the outer solar system

    International Nuclear Information System (INIS)

    Johnson, R.E.

    1987-01-01

    Voyager reflectance spectra data have indicated clear leading/trailing differences in the albedo of the icy Galilean and Saturian satellites. For the Galilean satellites, these have been analyzed by Nelson, et al. and, more recently, by McEwen. They have described the longitudinal dependence of this data and attempted to interpret this in terms of plasma and meteorite modification of the surface. Primary attention has been paid to Europa at which the leading/trailing differences are the largest. This data was reanalyzed extracting the single grain albedo (w) and constructing the Espat-function, W = (1-w)/w from this. Because w is near unity, W is approximately 2(alpha)D where alpha is the absorption coefficient and D is the grain size. In doing so, a direct comparison to the longitudinal plasma bombardment flux was found for the first time. This occurs primarily in the UV and is probably due to an absorption associated with implanted S, as the UV band of Voyager overlaps the IUE data of Lane et al. The relative importance of grain size effects and implant impurity effects can now be studied

  4. Surface modification and particles size distribution control in nano-CdS/polystyrene composite film

    International Nuclear Information System (INIS)

    Min Zhirong; Ming Qiuzhang; Hai Chunliang; Han Minzeng

    2003-01-01

    Preparation of nano-CdS particles with surface thiol modification by microemulsion method and their influences on the particle size distribution in highly filled polystyrene-based composites were studied. The modified nano-CdS was characterized by X-ray photoelectron spectroscopy (XPS), light absorption and emission measurements to reveal the morphologies of the surface modifier, which are consistent with the surface molecules packing calculation. The morphologies of the surface modifier exerted a great influence not only on the optical performance of the particles themselves, but also on the size distribution of the particle in polystyrene matrix. A monolayer coverage with tightly packed thiol molecules was believed to be most effective in promoting a uniform particle size distribution and eliminating the surface defects that cause radiationless recombination. Control of the particles size distribution in polystyrene can be attained by adjusting surface coverage status of the thiol molecules based on the strong interaction between the surface modifier and the matrix

  5. Effect of Surface Modification and Macrophage Phenotype on Particle Internalization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Daniel [Iowa State University; Phan, Ngoc [Iowa State University; Isely, Christopher [Iowa State University; Bruene, Lucas [Iowa State University; Bratlie, Kaitlin M [Ames Laboratory

    2014-11-10

    Material properties play a key role in the cellular internalization of polymeric particles. In the present study, we have investigated the effects of material characteristics such as water contact angle, zeta potential, melting temperature, and alternative activation of complement on particle internalization for pro-inflammatory, pro-angiogenic, and naïve macrophages by using biopolymers (~600 nm), functionalized with 13 different molecules. Understanding how material parameters influence particle internalization for different macrophage phenotypes is important for targeted delivery to specific cell populations. Here, we demonstrate that material parameters affect the alternative pathway of complement activation as well as particle internalization for different macrophage phenotypes. Here, we show that the quantitative structure–activity relationship method (QSAR) previously used to predict physiochemical properties of materials can be applied to targeting different macrophage phenotypes. These findings demonstrated that targeted drug delivery to macrophages could be achieved by exploiting material parameters.

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

    International Nuclear Information System (INIS)

    Kamiya, Hidehiro; Iijima, Motoyuki

    2010-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hidehiro Kamiya and Motoyuki Iijima

    2010-01-01

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

  8. Surface modification of Chlorella vulgaris cells using magnetite particles

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

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

  9. Functionality of porous silicon particles: Surface modification for biomedical applications

    International Nuclear Information System (INIS)

    Gallach, D.; Recio Sanchez, G.; Munoz Noval, A.; Manso Silvan, M.; Ceccone, G.; Martin Palma, R.J.; Torres Costa, V.; Martinez Duart, J.M.

    2010-01-01

    Porous silicon-based particles (PSps) with tailored physical and biological properties have recently attracted great attention given their biomedical potential. Within this context, the objective of the present work is to optimize the experimental parameters for the formation of biofunctional mesoporous PSps. Their functionality has been studied on the one hand by analyzing the fluorescence characteristics, such as tunable narrow band emission and fluorescence aging for PSps with different molecular capping. With regard to the biofunctional characteristics, two different molecular end-capping processes have been assayed: antifouling polyethylene glycol (PEG) and polar binding amino silanes (APTS), which were evaluated by X-ray photoelectron spectroscopy (XPS). Both PEG and APTS binding to the particles could be confirmed from the analysis of Si 2p and C 1s XPS core level spectra. The finding that these PSp-molecule conjugates allow the reduction of fluorescence degradation with time in solution is of interest for the development of cellular or tissue markers. From the morphological point of view, PEG termination is of special interest allowing the PSps after an ultrasonic treatment to get spherical shapes in the micron scale. The functionality as solid state dyes is preliminarily evaluated by direct fluorescence imaging.

  10. Functionality of porous silicon particles: Surface modification for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gallach, D.; Recio Sanchez, G.; Munoz Noval, A. [Departamento de Fisica Aplicada y Departamento de Biologia Molecular, Facultad de Ciencias, Cantoblanco, 28049 Madrid (Spain); Centro de Investigaciones Biomedicas en Red, Biomateriales, Bioingenieria y Nanomedicina (CIBERbbn) (Spain); Manso Silvan, M., E-mail: miguel.manso@uam.es [Departamento de Fisica Aplicada y Departamento de Biologia Molecular, Facultad de Ciencias, Cantoblanco, 28049 Madrid (Spain); Centro de Investigaciones Biomedicas en Red, Biomateriales, Bioingenieria y Nanomedicina (CIBERbbn) (Spain); Ceccone, G. [Institute for Health and Consumer Protection, European Commission, 21020 Ispra (Italy); Martin Palma, R.J.; Torres Costa, V.; Martinez Duart, J.M. [Departamento de Fisica Aplicada y Departamento de Biologia Molecular, Facultad de Ciencias, Cantoblanco, 28049 Madrid (Spain); Centro de Investigaciones Biomedicas en Red, Biomateriales, Bioingenieria y Nanomedicina (CIBERbbn) (Spain)

    2010-05-25

    Porous silicon-based particles (PSps) with tailored physical and biological properties have recently attracted great attention given their biomedical potential. Within this context, the objective of the present work is to optimize the experimental parameters for the formation of biofunctional mesoporous PSps. Their functionality has been studied on the one hand by analyzing the fluorescence characteristics, such as tunable narrow band emission and fluorescence aging for PSps with different molecular capping. With regard to the biofunctional characteristics, two different molecular end-capping processes have been assayed: antifouling polyethylene glycol (PEG) and polar binding amino silanes (APTS), which were evaluated by X-ray photoelectron spectroscopy (XPS). Both PEG and APTS binding to the particles could be confirmed from the analysis of Si 2p and C 1s XPS core level spectra. The finding that these PSp-molecule conjugates allow the reduction of fluorescence degradation with time in solution is of interest for the development of cellular or tissue markers. From the morphological point of view, PEG termination is of special interest allowing the PSps after an ultrasonic treatment to get spherical shapes in the micron scale. The functionality as solid state dyes is preliminarily evaluated by direct fluorescence imaging.

  11. Surface Modification of α-Fe Metal Particles by Chemical Surface Coating

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The structure of α-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  13. 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

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

    Directory of Open Access Journals (Sweden)

    Meina Xiao

    2018-06-01

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

  15. Transport of particles by surface waves: a modification of the classical bouncer model

    International Nuclear Information System (INIS)

    Ragulskis, M; Sanjuan, M A F

    2008-01-01

    We consider a ball under the influence of gravity on a platform. A propagating surface wave travels on the surface of the platform, while the platform remains motionless. This is a modification of the classical bouncing ball problem and describes the transport of particles by surface waves. Phase and velocity maps cannot be expressed in an explicit form owing to implicit formulations, and no formal analytical analysis is possible. Numerical analysis shows that the transition to chaos is produced via a period doubling route, which is a common property for classical bouncers. The bouncing process can be sensitive to the initial conditions, which can build the ground for control techniques that can dramatically increase the effectiveness of particle transport in practical applications

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

    Science.gov (United States)

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

    2015-05-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  18. Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

    Energy Technology Data Exchange (ETDEWEB)

    Buzi, Luxherta, E-mail: l.buzi@fz-juelich.de [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Université de Lorraine, Institut Jean Lamour, CNRS UMR 7198, Bvd. des Aiguillettes, F-54506 Vandoeuvre (France); Temmerman, Greg De [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Oost, Guido Van [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Möller, Sören [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany)

    2014-12-15

    Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10{sup 23} D{sup +}/m{sup 2} s and low: 9 · 10{sup 21} D{sup +}/m{sup 2} s). Particle fluence and ion energy, respectively 10{sup 26} D{sup +}/m{sup 2} and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion.

  19. Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

    International Nuclear Information System (INIS)

    Buzi, Luxherta; Temmerman, Greg De; Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker; Oost, Guido Van; Möller, Sören

    2014-01-01

    Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10 23 D + /m 2 s and low: 9 · 10 21 D + /m 2 s). Particle fluence and ion energy, respectively 10 26 D + /m 2 and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion

  20. A new setup for the investigation of swift heavy ion induced particle emission and surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Meinerzhagen, F.; Breuer, L.; Bukowska, H.; Herder, M.; Schleberger, M.; Wucher, A. [Fakultät für Physik, Universität Duisburg-Essen and Cenide, 47057 Duisburg (Germany); Bender, M.; Severin, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Lebius, H. [CIMAP (CEA-CNRS-ENSICAEN-UCN), 14070 Caen Cedex 5 (France)

    2016-01-15

    The irradiation with fast ions with kinetic energies of >10 MeV leads to the deposition of a high amount of energy along their trajectory (up to several ten keV/nm). The energy is mainly transferred to the electronic subsystem and induces different secondary processes of excitations, which result in significant material modifications. A new setup to study these ion induced effects on surfaces will be described in this paper. The setup combines a variable irradiation chamber with different techniques of surface characterizations like scanning probe microscopy, time-of-flight secondary ion, and neutral mass spectrometry, as well as low energy electron diffraction under ultra high vacuum conditions, and is mounted at a beamline of the universal linear accelerator (UNILAC) of the GSI facility in Darmstadt, Germany. Here, samples can be irradiated with high-energy ions with a total kinetic energy up to several GeVs under different angles of incidence. Our setup enables the preparation and in situ analysis of different types of sample systems ranging from metals to insulators. Time-of-flight secondary ion mass spectrometry enables us to study the chemical composition of the surface, while scanning probe microscopy allows a detailed view into the local electrical and morphological conditions of the sample surface down to atomic scales. With the new setup, particle emission during irradiation as well as persistent modifications of the surface after irradiation can thus be studied. We present first data obtained with the new setup, including a novel measuring protocol for time-of-flight mass spectrometry with the GSI UNILAC accelerator.

  1. Effects of temperature on surface modification of W exposed to He particles

    International Nuclear Information System (INIS)

    Li, C.; Greuner, H.; Yuan, Y.; Luo, G.N.; Böswirth, B.; Fu, B.Q.; Xu, H.Y.; Jia, Y.Z.; Liu, W.

    2014-01-01

    Highlights: • Blisters were observed on W surface under He beam heating at ∼950 °C. • He-induced blistering shows a clear grain orientation dependence. • An evolution to a coral-like structure was observed under loading at ∼2700 °C. • A texture with 〈0 0 1〉 parallel to the surface normal direction will be beneficial. - Abstract: The effect of combined heating and helium particle flux on annealed tungsten samples has been studied in the neutral beam facility GLADIS. He beams with power densities of 2.4 MW/m 2 and 9.5 MW/m 2 were used to adiabatically load the samples to peak surface temperatures from ∼950 °C (1223 K) to ∼2700 °C (2973 K). Changes in the surface morphology resulting from combined heat and the flux exposure were studied for He fluences up to 3 × 10 22 /m 2 . Typical structures for the sample loaded at ∼950 °C (1223 K) were blisters with a clear grain orientation dependence and the largest blisters formed on grains with 〈0 0 1〉 surface normal. However at higher temperatures, blistering was more easily suppressed for grains near this orientation because the growth of larger blister takes place more slowly. An evolution from a “porous structure” to a “coral-like structure” with increasing fluence was observed on the samples loaded at the highest temperature. Based on these results mechanisms for surface modification at different temperatures are discussed and a texture with 〈0 0 1〉 parallel to the normal direction of the grains is suggested to optimize the plasma facing material due to their stronger resistance to early stage blistering

  2. Optimizing critical heat flux enhancement through nano-particle-based surface modifications

    International Nuclear Information System (INIS)

    Truong, B.; Hu, L. W.; Buongiorno, J.

    2008-01-01

    Colloidal dispersions of nano-particles, also known as nano-fluids, have shown to yield significant Critical Heat Flux (CHF) enhancement. The CHF enhancement mechanism in nano-fluids is due to the buildup of a porous layer of nano-particles upon boiling. Unlike microporous coatings that had been studied extensively, nano-particles have the advantages of forming a thin layer on the substrate with surface roughness ranges from the sub-micron to several microns. By tuning the chemical properties it is possible to coat the nano-particles in colloidal dispersions onto the desired surface, as has been demonstrated in engineering thin film industry. Building on recent work conducted at MIT, this paper illustrates the maximum CHF enhancement that can be achieved based on existing correlations. Optimization of the CHF enhancement by incorporation of key factors, such as the surface wettability and roughness, will also be discussed. (authors)

  3. Surface modification of silica particles and its effects on cure and mechanical properties of the natural rubber composites

    Energy Technology Data Exchange (ETDEWEB)

    Theppradit, Thawinan [Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, Pattarapan [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Poompradub, Sirilux, E-mail: sirilux.p@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

    2014-12-15

    The efficiency of modified silica (SiO{sub 2}) particles in the reinforcement of natural rubber (NR) vulcanizates was evaluated. The SiO{sub 2} particles were synthesized via a sol–gel reaction using tetraethyl orthosilicate as the precursor, and then the formed SiO{sub 2} particles were modified with methyl, vinyl or aminopropyl groups using methyltriethoxysilane, vinyltriethoxysilane or aminopropyltrimethoxysilane, respectively. Fourier transform infrared spectroscopy and elemental analysis confirmed the successful modification of the surface of the silica particles. The water contact angle measurement revealed the greater hydrophobicity of the three modified silica preparations compared to the unmodified SiO{sub 2}. NR vulcanizates filled with modified SiO{sub 2} particles were prepared and the mechanical, thermal and dynamic mechanical properties of composites were investigated. The morphology of composite materials was also investigated by scanning electron microscopy. The modified SiO{sub 2} particles were well dispersed in the NR matrix leading to the good compatibility between the rubber and filler, and so an improved cure, mechanical, thermal and dynamic mechanical properties of the composite vulcanizate materials. - Highlights: • Modification of SiO{sub 2} particles by MTES, VTES and APTES. • Improvement of hydrophobicity of SiO{sub 2} particle and compatibility between SiO{sub 2} and rubbery matrix. • Improvement of cure, mechanical, thermal, dynamic mechanical properties of NR vulcanizates.

  4. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  5. Sandblasting as a surface modification technique on titanium alloys for biomedical applications: abrasive particle behavior

    International Nuclear Information System (INIS)

    Balza, J C; Zujur, D; Delvasto, P; Gil, L; Subero, R; Dominguez, E; Alvarez, J

    2013-01-01

    The present work shows the analysis of a sandblasting process using alumina abrasive particles on Ti-6Al-4V surfaces. The metallic samples were first characterized by optical microscopy (OM), revealing an α+β microstructure with a Widmanstätten morphology. Topography of the samples was assessed by scanning electron microscopy (SEM), before and after sandblasting. The Al 2 O 3 particles used had a granulometric distribution between 420 and 850 μm, with a median particle size (d50) of 670 μm, which decreased to 420 μm after sandblasting for 10 seconds. This change in the size of the particles generated a loss on particle kinetic energy by a factor of 3.5. Such variation on processing conditions induced a progressive increase on average roughness (Ra) of the Ti-6Al-4V surfaces, until the first 7 seconds were reached. From that point on, a reverse process was observed, exerting a polishing effect on the surface of the Ti-6Al-4V alloy.

  6. Surface modification of submicronic TiO{sub 2} particles prepared by ultrasonic spray pyrolysis for visible light absorption

    Energy Technology Data Exchange (ETDEWEB)

    Dugandzic, Ivan M. [Institute of Technical Sciences of SASA (Serbia); Jovanovic, Dragana J. [University of Belgrade, Vinca Institute of Nuclear Sciences (Serbia); Mancic, Lidija T. [Institute of Technical Sciences of SASA (Serbia); Zheng, Nan; Ahrenkiel, Scott P. [South Dakota School of Mines and Technology (United States); Milosevic, Olivera B. [Institute of Technical Sciences of SASA (Serbia); Saponjic, Zoran V.; Nedeljkovic, Jovan M., E-mail: jovned@vinca.rs [University of Belgrade, Vinca Institute of Nuclear Sciences (Serbia)

    2012-10-15

    Spherical, submicronic TiO{sub 2} assemblage with high specific surface area and controllable phase composition was prepared in the process of ultrasonic spray drying/pyrolysis in a wide temperature range (150-800 Degree-Sign C) by using as a precursor aqueous colloidal solution consisting of TiO{sub 2} nanoparticles (4.5 nm). Submicronic, soft and grained spherical TiO{sub 2} particles (d = 370-500 nm) comprising clustered nanocrystals (<10 nm) were obtained at low processing temperature, while particle densification, intensive growth of the clustered primary units and anatase-to-rutile transformation ({approx}30 wt%) were observed at the higher temperatures. Detailed structural and morphological characterisation were performed by X-ray powder diffraction, scanning and field emission electron microscopy, transmission electron microscopy, and laser particle size analysis. Moreover, the surface modification of TiO{sub 2} particles through the formation of charge-transfer (CT) complex was achieved with different ligands: ascorbic acid, dopamine, catechol, 2,3-dihydroxynaphthalene, and anthrarobin. Optical properties of the surface-modified TiO{sub 2} particles were studied by using diffuse reflection spectroscopy. The binding structure between the surface titanium atoms and different ligands was determined by using Fourier transform infrared spectroscopy. The formation of CT complexes induced significant red shift of optical absorption in comparison to unmodified TiO{sub 2} particles.

  7. Surface modification of BMN particles with silane coupling agent for composites with PTFE

    Science.gov (United States)

    Qi, Yanyuan; Luo, Qing; Shen, Jie; Zheng, Liu; Zhou, Jing; Chen, Wen

    2017-08-01

    Polymer-ceramic dielectric composites, which possess better dielectric properties, flexibility, ease in processing and shaping since they combine the advantages of polymers and dielectric ceramics, are widely used in microwave substrate applications. In order to optimize the properties of the composites, it is necessary to enhance the compatibility between the polymer matrix and ceramic filler because of their tremendous difference. In this paper, the vinyltrimethoxysilane (VTMS) is used to modify the Ba(Mg1/3Nb2/3)O3 (BMN) ceramic particles which can improve the compatibility between BMN ceramics and PTFE and the distribution of BMN in polytetrafluoroethylene (PTFE). The modification of VTMS has no influence on the crystal structure of BMN ceramics and the compact VTMS modified BMN/PTFE composites with satisfactory uniformity and less cavities are obtained. The relative permittivity (εr) of VTMS modified BMN/PTFE composite substrate is 5.84 while the loss tangent reaches 1.5 × 10-3 at microwave frequencies (around 10 GHz).

  8. Chemical surface modification of calcium carbonate particles with stearic acid using different treating methods

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zhi [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland); Daly, Michael [Mergon International, Castlepollard, Westmeath (Ireland); Clémence, Lopez [Polytech Grenoble, Grenoble (France); Geever, Luke M.; Major, Ian; Higginbotham, Clement L. [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland); Devine, Declan M., E-mail: ddevine@ait.ie [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland)

    2016-08-15

    Highlights: • The effects of stearic acid treatment for CaCO{sub 3} are highly influenced by the treatment method of application. • A new stearic acid treatment method, namely, combination treatment for CaCO{sub 3} was developed. • The combination treatment was compared with two of the existing methods dry and wet method. • The negative effects of void coalescence was minimised by the utilization of the combination method. - Abstract: Calcium carbonate (CaCO{sub 3}) is often treated with stearic acid (SA) to decrease its polarity. However, the method of application of the SA treatments has a strong influence on CaCO{sub 3} thermoplastic composite’s interfacial structure and distribution. Several of papers describe the promising effects of SA surface treatment, but few compare the treatment process and its effect on the properties of the final thermoplastic composite. In the current study, we assessed a new SA treatment method, namely, complex treatment for polymer composite fabrication with HDPE. Subsequently, a comparative study was performed between the “complex” process and the other existing methods. The composites were assessed using different experiments included scanning electron microscopy (SEM), void content, density, wettability, differential scanning calorimetry (DSC), and tensile tests. It was observed that the “complex” surface treatment yielded composites with a significantly lower voids content and higher density compared to other surface treatments. This indicates that after the “complex” treatment process, the CaCO{sub 3} particles and HDPE matrix are more tightly packed than other methods. DSC and wettability results suggest that the “wet” and “complex” treated CaCO{sub 3} composites had a significantly higher heat of fusion and moisture resistance compared to the “dry” treated CaCO{sub 3} composites. Furthermore, “wet” and “complex” treated CaCO{sub 3} composites have a significantly higher tensile

  9. Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization

    Directory of Open Access Journals (Sweden)

    Ha ES

    2015-06-01

    Full Text Available Eun-Sol Ha,1 In-hwan Baek,2 Jin-Wook Yoo,1 Yunjin Jung,1 Min-Soo Kim1 1College of Pharmacy, Pusan National University, 2College of Pharmacy, Kyungsung University, Busan, Republic of Korea Abstract: The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8 and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC0→12 h and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate. Keywords: solubility, wettability, sucrose laurate, cellulose

  10. SEM observations of particle track membrane surfaces modificated using plasma treatment

    International Nuclear Information System (INIS)

    Sartowska, B.; Buczkowski, M.; Starosta, W.

    2003-01-01

    This work presents results of scanning electron microscopy (SEM) observations of 0.4 μm membranes after plasma treatment with different parameters. The morphology changes at the surfaces and at the pore walls were observed. The character of changes in the membrane parameters according to the process conditions was determined

  11. Surface modification of amorphous nanosilica particles suppresses nanosilica-induced cytotoxicity, ROS generation, and DNA damage in various mammalian cells

    International Nuclear Information System (INIS)

    Yoshida, Tokuyuki; Yoshioka, Yasuo; Matsuyama, Keigo; Nakazato, Yasutaro; Tochigi, Saeko; Hirai, Toshiro; Kondoh, Sayuri; Nagano, Kazuya; Abe, Yasuhiro; Kamada, Haruhiko; Tsunoda, Shin-ichi; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Tsutsumi, Yasuo

    2012-01-01

    Highlights: ► There is increasing concern regarding the potential health risks of nanomaterials. ► We evaluated the effect of surface properties of nanomaterials on cellular responses. ► We showed that the surface properties play an important in determining its safety. ► These data provide useful information for producing safer nanomaterials. -- Abstract: Recently, nanomaterials have been utilized in various fields. In particular, amorphous nanosilica particles are increasingly being used in a range of applications, including cosmetics, food technology, and medical diagnostics. However, there is concern that the unique characteristics of nanomaterials might induce undesirable effects. The roles played by the physical characteristics of nanomaterials in cellular responses have not yet been elucidated precisely. Here, by using nanosilica particles (nSPs) with a diameter of 70 nm whose surface was either unmodified (nSP70) or modified with amine (nSP70-N) or carboxyl groups (nSP70-C), we examined the relationship between the surface properties of nSPs and cellular responses such as cytotoxicity, reactive oxygen species (ROS) generation, and DNA damage. To compare the cytotoxicity of nSP70, nSP70-N, or nSP70-C, we examined in vitro cell viability after nSP treatment. Although the susceptibility of each cell line to the nSPs was different, nSP70-C and nSP70-N showed lower cytotoxicity than nSP70 in all cell lines. Furthermore, the generation of ROS and induction of DNA damage in nSP70-C- and nSP70-N-treated cells were lower than those in nSP70-treated cells. These results suggest that the surface properties of nSP70 play an important role in determining its safety, and surface modification of nSP70 with amine or carboxyl groups may be useful for the development of safer nSPs. We hope that our results will contribute to the development of safer nanomaterials.

  12. Surface modification of silica particles with gold nanoparticles as an augmentation of gold nanoparticle mediated laser perforation

    Science.gov (United States)

    Kalies, Stefan; Gentemann, Lara; Schomaker, Markus; Heinemann, Dag; Ripken, Tammo; Meyer, Heiko

    2014-01-01

    Gold nanoparticle mediated (GNOME) laser transfection/perforation fulfills the demands of a reliable transfection technique. It provides efficient delivery and has a negligible impact on cell viability. Furthermore, it reaches high-throughput applicability. However, currently only large gold particles (> 80 nm) allow successful GNOME laser perforation, probably due to insufficient sedimentation of smaller gold nanoparticles. The objective of this study is to determine whether this aspect can be addressed by a modification of silica particles with gold nanoparticles. Throughout the analysis, we show that after the attachment of gold nanoparticles to silica particles, comparable or better efficiencies to GNOME laser perforation are reached. In combination with 1 µm silica particles, we report laser perforation with gold nanoparticles with sizes down to 4 nm. Therefore, our investigations have great importance for the future research in and the fields of laser transfection combined with plasmonics. PMID:25136494

  13. Relationship between size and surface modification of silica particles and enhancement and suppression of inflammatory cytokine production by lipopolysaccharide- or peptidoglycan-stimulated RAW264.7 macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, Eiichiro, E-mail: uemura-e@phs.osaka-u.ac.jp; Yoshioka, Yasuo, E-mail: y-yoshioka@biken.osaka-u.ac.jp; Hirai, Toshiro, E-mail: toshiro.hirai@pitt.edu; Handa, Takayuki, E-mail: handa-t@phs.osaka-u.ac.jp; Nagano, Kazuya, E-mail: knagano@phs.osaka-u.ac.jp; Higashisaka, Kazuma, E-mail: higashisaka@phs.osaka-u.ac.jp; Tsutsumi, Yasuo, E-mail: ytsutsumi@phs.osaka-u.ac.jp [Osaka University, Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences (Japan)

    2016-06-15

    Although nanomaterials are used in an increasing number of commodities, the relationships between their immunotoxicity and physicochemical properties such as size or surface characteristics are not fully understood. Here we demonstrated that pretreatment with amorphous silica particles (SPs) of various sizes (diameters of 10–1000 nm), with or without amine surface modification, significantly decreased interleukin 6 production by RAW264.7 macrophages following lipopolysaccharide or peptidoglycan stimulation. Furthermore, nanosized, but not microsized, SPs significantly enhanced tumor necrosis factor-α production in macrophages stimulated with lipopolysaccharide. This altered cytokine response was distinct from the inflammatory responses induced by treatment with the SPs alone. Additionally, the uptake of SPs into macrophages by phagocytosis was found to be crucial for the suppression of macrophage immune response to occur, irrespective of particle size or surface modification. Together, these results suggest that SPs may not only increase susceptibility to microbial infection, but that they may also be potentially effective immunosuppressants.

  14. Relationship between size and surface modification of silica particles and enhancement and suppression of inflammatory cytokine production by lipopolysaccharide- or peptidoglycan-stimulated RAW264.7 macrophages

    International Nuclear Information System (INIS)

    Uemura, Eiichiro; Yoshioka, Yasuo; Hirai, Toshiro; Handa, Takayuki; Nagano, Kazuya; Higashisaka, Kazuma; Tsutsumi, Yasuo

    2016-01-01

    Although nanomaterials are used in an increasing number of commodities, the relationships between their immunotoxicity and physicochemical properties such as size or surface characteristics are not fully understood. Here we demonstrated that pretreatment with amorphous silica particles (SPs) of various sizes (diameters of 10–1000 nm), with or without amine surface modification, significantly decreased interleukin 6 production by RAW264.7 macrophages following lipopolysaccharide or peptidoglycan stimulation. Furthermore, nanosized, but not microsized, SPs significantly enhanced tumor necrosis factor-α production in macrophages stimulated with lipopolysaccharide. This altered cytokine response was distinct from the inflammatory responses induced by treatment with the SPs alone. Additionally, the uptake of SPs into macrophages by phagocytosis was found to be crucial for the suppression of macrophage immune response to occur, irrespective of particle size or surface modification. Together, these results suggest that SPs may not only increase susceptibility to microbial infection, but that they may also be potentially effective immunosuppressants.

  15. Dependency of Nanodiamond Particle Size and Outermost-Surface Composition on Organo-Modification: Evaluation by Formation of Organized Molecular Films and Nanohybridization with Organic Polymers.

    Science.gov (United States)

    Tasaki, Taira; Guo, Yifei; Meng, Qi; Mamun, Muhammad Abdullah Al; Kasahara, Yusuke; Akasaka, Shuichi; Fujimori, Atsuhiro

    2017-04-26

    The formation behavior of organized organo-modified nanodiamond films and polymer nanocomposites has been investigated using nanodiamonds of several different particle sizes and outermost-surface compositions. The nanodiamond particle sizes used in this study were 3 and 5 nm, and the outermost surface contained -OH and/or -COOH groups. The nanodiamond was organo-modified to prepare -OH 2 + cations and -COO - anions on the outermost surface by carboxylic anion of fatty acid and long-chain phosphonium cation, respectively. The surface of nanodiamond is known to be covered with a nanolayer of adsorbed water, which was exploited here for the organo-modification of nanodiamond with long-chain fatty acids via adsorption, leading to nanodispersions of nanodiamond in general organic solvents as a mimic of solvency. Particle multilayers were then formed via the Langmuir-Blodgett technique and subjected to fine structural analysis. The organo-modification enabled integration and multilayer formation of inorganic nanoparticles due to enhancement of the van der Waals interactions between the chains. Therefore, "encounters" between the organo-modifying chain and the inorganic particles led to solubilization of the inorganic particles and enhanced interactions between the particles; this can be regarded as imparting a new functionality to the organic molecules. Nanocomposites with a transparent crystalline polymer were fabricated by nanodispersing the nanodiamond into the polymer matrix, which was achievable due to the organo-modification. The resulting transparent nanocomposites displayed enhanced degrees of crystallization and improved crystallization temperatures, compared with the neat polymer, due to a nucleation effect.

  16. Structure modification of particle track membranes

    International Nuclear Information System (INIS)

    Lueck, H.B.; Gemende, B.; Heinrich, B.

    1991-01-01

    Three different structure modifications were studied in order to improve the flux and dirt loading capacity of particle track membranes without affecting their retention characteristic. Divergent irradiation is a very effective tool for decreasing the number of multiple pores and increasing the porosity up to 20 per cent. The technique leads to a remarkable but not efficient enhancement of the surface porosity. Improved surface porosity produced by a double irradiation technique turns out to be very effective with respect to the filtration performance. (author)

  17. Fabrication and Modification of Nanoporous Silicon Particles

    Science.gov (United States)

    Ferrari, Mauro; Liu, Xuewu

    2010-01-01

    Silicon-based nanoporous particles as biodegradable drug carriers are advantageous in permeation, controlled release, and targeting. The use of biodegradable nanoporous silicon and silicon dioxide, with proper surface treatments, allows sustained drug release within the target site over a period of days, or even weeks, due to selective surface coating. A variety of surface treatment protocols are available for silicon-based particles to be stabilized, functionalized, or modified as required. Coated polyethylene glycol (PEG) chains showed the effective depression of both plasma protein adsorption and cell attachment to the modified surfaces, as well as the advantage of long circulating. Porous silicon particles are micromachined by lithography. Compared to the synthesis route of the nanomaterials, the advantages include: (1) the capability to make different shapes, not only spherical particles but also square, rectangular, or ellipse cross sections, etc.; (2) the capability for very precise dimension control; (3) the capacity for porosity and pore profile control; and (4) allowance of complex surface modification. The particle patterns as small as 60 nm can be fabricated using the state-of-the-art photolithography. The pores in silicon can be fabricated by exposing the silicon in an HF/ethanol solution and then subjecting the pores to an electrical current. The size and shape of the pores inside silicon can be adjusted by the doping of the silicon, electrical current application, the composition of the electrolyte solution, and etching time. The surface of the silicon particles can be modified by many means to provide targeted delivery and on-site permanence for extended release. Multiple active agents can be co-loaded into the particles. Because the surface modification of particles can be done on wafers before the mechanical release, asymmetrical surface modification is feasible. Starting from silicon wafers, a treatment, such as KOH dipping or reactive ion

  18. Surfactant adsorption and aggregate structure of silica nanoparticles: a versatile stratagem for the regulation of particle size and surface modification

    International Nuclear Information System (INIS)

    Chaudhary, Savita; Rohilla, Deepak; Mehta, S K

    2014-01-01

    The area of silica nanoparticles is incredibly polygonal. Silica particles have aroused exceptional deliberation in bio-analysis due to great progress in particular arenas, for instance, biocompatibility, unique properties of modifiable pore size and organization, huge facade areas and pore volumes, manageable morphology and amendable surfaces, elevated chemical and thermal stability. Currently, silica nanoparticles participate in crucial utilities in daily trade rationales such as power storage, chemical and genetic sensors, groceries dispensation and catalysis. Herein, the size-dependent interfacial relation of anionic silica nanoparticles with twelve altered categories of cationic surfactants has been carried out in terms of the physical chemical facets of colloid and interface science. The current analysis endeavours to investigate the virtual consequences of different surfactants through the development of the objective composite materials. The nanoparticle size controls, the surface-to-volume ratio and surface bend relating to its interaction with surfactant will also be addressed in this work. More importantly, the simulated stratagem developed in this work can be lengthened to formulate core–shell nanostructures with functional nanoparticles encapsulated in silica particles, making this approach valuable and extensively pertinent for employing sophisticated materials for catalysis and drug delivery. (papers)

  19. Surface modification of 2014 aluminium alloy-Al2O3 particles composites by nickel electrochemical deposition

    International Nuclear Information System (INIS)

    Molina, J.M.; Saravanan, R.A.; Narciso, J.; Louis, E.

    2004-01-01

    A method to modify the surface of aluminium matrix composites (AMC) by electrochemical nickel deposition has been developed. Deposition was carried out in a stirred standard Watt's bath, whereas potential and time were varied to optimize coating characteristics. The method, that allowed to overcome the serious difficulties associated to electrochemical deposition of an inherently inhomogeneous material, was used to nickel coat composites of 2014 aluminium alloy-15 vol.% Al 2 O 3 particles. Coats with a good adherence and up to 60 μm thick were easily obtained. In order to improve surface properties, the coated composite was subjected to rather long (from 10 to 47.5 h) heat treatments at a temperature of 520 deg,C. The heat treatments improved the uniformity of the deposited layer and promoted the formation of Al-Ni intermetallics (mainly Al 3 Ni 2 , as revealed by X-ray diffraction and energy-dispersive X-ray analysis (EDX)). Experimental results indicate that growth of the intermetallic layer is diffusion limited

  20. Microscale surface modifications for heat transfer enhancement.

    Science.gov (United States)

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

    2013-10-09

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

  1. The surface modification of polystyrene

    International Nuclear Information System (INIS)

    Tremlett, C.

    2000-03-01

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

  2. Effects of Surface Modification of Nanodiamond Particles for Nucleation Enhancement during Its Film Growth by Microwave Plasma Jet Chemical Vapour Deposition Technique

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2014-01-01

    Full Text Available The seedings of the substrate with a suspension of nanodiamond particles (NDPs were widely used as nucleation seeds to enhance the growth of nanostructured diamond films. The formation of agglomerates in the suspension of NDPs, however, may have adverse impact on the initial growth period. Therefore, this paper was aimed at the surface modification of the NDPs to enhance the diamond nucleation for the growth of nanocrystalline diamond films which could be used in photovoltaic applications. Hydrogen plasma, thermal, and surfactant treatment techniques were employed to improve the dispersion characteristics of detonation nanodiamond particles in aqueous media. The seeding of silicon substrate was then carried out with an optimized spin-coating method. The results of both Fourier transform infrared spectroscopy and dynamic light scattering measurements demonstrated that plasma treated diamond nanoparticles possessed polar surface functional groups and attained high dispersion in methanol. The nanocrystalline diamond films deposited by microwave plasma jet chemical vapour deposition exhibited extremely fine grain and high smooth surfaces (~6.4 nm rms on the whole film. These results indeed open up a prospect of nanocrystalline diamond films in solar cell applications.

  3. Corrosion principles and surface modification

    International Nuclear Information System (INIS)

    Kruger, J.

    1982-01-01

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

  4. Andromede project: Surface analysis and modification with probes from hydrogen to nano-particles in the MeV energy range

    International Nuclear Information System (INIS)

    Eller, Michael J.; Cottereau, Evelyne; Rasser, Bernard; Verzeroli, Elodie; Agnus, Benoit; Gaubert, Gabriel; Donzel, Xavier; Delobbe, Anne; Della-Negra, Serge

    2015-01-01

    The Andromede project is the center of a multi-disciplinary team which will build a new instrument for surface modification and analysis using the impact of probes from hydrogen to nano-particles (Au 400 +4 ) in the MeV range. For this new instrument a series of atomic, polyatomic, molecular and nano-particle ion beams will be delivered using two ion sources in tandem, a liquid metal ion source and an electron cyclotron resonance source. The delivered ion beams will be accelerated to high energy with a 4 MeV van de Graaff type accelerator. By using a suite of probes in the MeV energy range, ion beam analysis techniques, MeV atomic and cluster secondary ion mass spectrometry can all be performed in one location. A key feature of the instrument is its ability to produce an intense beam for injection into the accelerator. The commissioning of the two sources shows that intense beams from atomic ions to nano-particles can be delivered for subsequent acceleration. The calculations and measurements for the two sources are presented.

  5. 钛酸酯偶联剂对包硅铝钛白粉表面的有机改性%Surface Organic Modification of SiO2 & Al2O3 Coated TiO2 Particles with Titanate Coupling Reagent

    Institute of Scientific and Technical Information of China (English)

    林玉兰; 王亭杰; 覃操; 金涌

    2001-01-01

    The surface organic modification of TiO2 particles with titanate coupling reagent,which was pre-coated with double layers of SiO2 and Al2O3,was studied.Experiments showed that the modified particles exhibited hydrophobic characteristics.The modification state of the particle surface was characterized by IR spectroscopic measurement,pyrolytic gas chromatography,thermogravimetric analysis and X-ray photoelectron spectra.The titanate coupling reagent binding with the hydroxyl on the particle surface was analyzed.The surface characteristics of pre-modification and post-modification particles were compared.

  6. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

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

  7. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

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

  8. Surface Modification for Microreactor Fabrication

    Directory of Open Access Journals (Sweden)

    Wladyslaw Torbicz

    2006-04-01

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

  9. Energy conservation potential of surface modification technologies

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-09-01

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

  10. Laser surface modification of PEEK

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-15

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

  11. Surface modification of metals by ion implantation

    International Nuclear Information System (INIS)

    Iwaki, Masaya

    1988-01-01

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

  12. Particle Distribution Modification by Low Amplitude Modes

    International Nuclear Information System (INIS)

    White, R.B.; Gorelenkov, N.; Heidbrink, W.W.; Van Zeeland, M.A.

    2009-01-01

    Modification of a high energy particle distribution by a spectrum of low amplitude modes is investigated using a guiding center code. Only through resonance are modes effective in modifying the distribution. Diagnostics are used to illustrate the mode-particle interaction and to find which effects are relevant in producing significant resonance, including kinetic Poincare plots and plots showing those orbits with time averaged mode-particle energy transfer. Effects of pitch angle scattering and drag are studied, as well as plasma rotation and time dependence of the equilibrium and mode frequencies. A specific example of changes observed in a DIII-D deuterium beam distribution in the presence of low amplitude experimentally validated Toroidal Alfven (TAE) eigenmodes and Reversed Shear Alfven (RSAE) eigenmodes is examined in detail. Comparison with experimental data shows that multiple low amplitude modes can account for significant modification of high energy beam particle distributions. It is found that there is a stochastic threshold for beam profile modification, and that the experimental amplitudes are only slightly above this threshold.

  13. Surface modifications of dental implants.

    Science.gov (United States)

    Stanford, C M

    2008-06-01

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

  14. Modification of Particle Distributions by MHD Instabilities II

    International Nuclear Information System (INIS)

    White, Roscoe B.

    2011-01-01

    The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution in an island due to phase mixing and portions of phase space becoming stochastic lead to modification of the particle distribution, a process extremely rapid in the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Large amplitude modes can cause profile avalanche and particle loss. Thus it is very valuable to be able to predict the temporal evolution of a particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we further develop and investigate the use of a new method of determining domains of phase space in which good KAM surfaces do not exist and use this method to examine a well documented case of profile modification by instabilities.

  15. Proton Conductivity of Nafion/Ex-Situ Sulfonic Acid-Modified Stöber Silica Nanocomposite Membranes As a Function of Temperature, Silica Particles Size and Surface Modification

    Science.gov (United States)

    Muriithi, Beatrice; Loy, Douglas A.

    2016-01-01

    The introduction of sulfonic acid modified silica in Nafion nanocomposite membranes is a good method of improving the Nafion performance at high temperature and low relative humidity. Sulfonic acid-modified silica is bifunctional, with silica phase expected to offer an improvement in membranes hydration while sulfonic groups enhance proton conductivity. However, as discussed in this paper, this may not always be the case. Proton conductivity enhancement of Nafion nanocomposite membranes is very dependent on silica particle size, sometimes depending on experimental conditions, and by surface modification. In this study, Sulfonated Preconcentrated Nafion Stober Silica composites (SPNSS) were prepared by modification of Stober silica particles with mercaptopropyltriethoxysilane, dispersing the particles into a preconcentrated solution of Nafion, then casting the membranes. The mercapto groups were oxidized to sulfonic acids by heating the membranes in 10 wt % hydrogen peroxide for 1 h. At 80 °C and 100% relative humidity, a 20%–30% enhancement of proton conductivity was only observed when sulfonic acid modified particle less than 50 nm in diameter were used. At 120 °C, and 100% humidity, proton conductivity increased by 22%–42% with sulfonated particles with small particles showing the greatest enhancement. At 120 °C and 50% humidity, the sulfonated particles are less efficient at keeping the membranes hydrated, and the composites underperform Nafion and silica-Nafion nanocomposite membranes. PMID:26828525

  16. A Simple Surface Modification of NiO Cathode with TiO2 Nano-Particles for Molten Carbonate Fuel Cells (MCFCs)

    International Nuclear Information System (INIS)

    Choi, Hee Seon; Kim, Keon; Yi, Cheolwoo

    2014-01-01

    The TiO 2 -modified Ni powders, prepared by the simple method (ball-milling and subsequent annealing) without resorting to any complex coating process, eventually form nickel titanate passive layer at high temperature. It as good corrosion resistance in molten carbonates media and higher electrical conductivity at high temperature. In addition, the modified cathode increases the degree of lithiation during the operation of MCFC. These positive effects provide a decrease in the internal resistance and improve the cell performance. Results obtained from this study can be applied to develop the surface modification of cathode materials and the performance of molten carbonate fuel cells. Molten carbonate fuel cells (MCFCs) are efficient energy conversion devices to convert chemical energy into electrical energy through the electrochemical reaction. Because of a lot of advantages of MCFC operated at high temperature, many researchers have been trying to apply it to large-scaled power generations, marine boats, and so on. Among various cathode materials, nickel oxide, NiO, is the most widely used cathode for MCFCs due to its stability and high electrical conductivity, but the degradation of cathode material, so-called NiO dissolution, prevents a long-term operation of MCFC. In order to overcome the drawback, numerous studies have been performed. One of the most useful ways to enhance the surface property and maintain the bulk property of the host materials is the surface modification. The most common modification method is coating and these coating procedures which need some complicated steps with the use of organic materials, but it restricts the large-scale fabrication. In this study, to improve the electrochemical performance, we have prepared an alternative MCFC cathode material, TiO 2 -modified NiO, by simple method without resorting to any complex coating process. Results obtained in this study can provide an effective way to mass-produce the cathode materials

  17. Electrochemical surface modification of titanium in dentistry.

    Science.gov (United States)

    Kim, Kyo-Han; Ramaswamy, Narayanan

    2009-01-01

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

  18. Covalent Surface Modifications of Carbon Nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

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

  19. Uniform Surface Modification of 3D Bioglass®-Based Scaffolds with Mesoporous Silica Particles (MCM-41) for Enhancing Drug Delivery Capability

    Science.gov (United States)

    Boccardi, Elena; Philippart, Anahí; Juhasz-Bortuzzo, Judith A.; Beltrán, Ana M.; Novajra, Giorgia; Vitale-Brovarone, Chiara; Spiecker, Erdmann; Boccaccini, Aldo R.

    2015-01-01

    The design and characterization of a new family of multifunctional scaffolds based on bioactive glass (BG) of 45S5 composition for bone tissue engineering and drug delivery applications are presented. These BG-based scaffolds are developed via a replication method of polyurethane packaging foam. In order to increase the therapeutic functionality, the scaffolds were coated with mesoporous silica particles (MCM-41), which act as an in situ drug delivery system. These sub-micron spheres are characterized by large surface area and pore volume with a narrow pore diameter distribution. The solution used for the synthesis of the silica mesoporous particles was designed to obtain a high-ordered mesoporous structure and spherical shape – both are key factors for achieving the desired controlled drug release. The MCM-41 particles were synthesized directly inside the BG-based scaffolds, and the drug-release capability of this combined system was evaluated. Moreover, the effect of MCM-41 particle coating on the bioactivity of the BG-based scaffolds was assessed. The results indicate that it is possible to obtain a multifunctional scaffold system characterized by high and interconnected porosity, high bioactivity, and sustained drug delivery capability. PMID:26594642

  20. Surface modification and characterization Collaborative Research Center at ORNL

    International Nuclear Information System (INIS)

    1986-01-01

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

  1. Surface Modification Of Implants For Bone Surgery

    Directory of Open Access Journals (Sweden)

    Marciniak J.

    2015-09-01

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

  2. Modification of Particle Distributions By MHD Instabilities I

    International Nuclear Information System (INIS)

    White, R.B.

    2010-01-01

    The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution due to phase mixing in an island or due to portions of phase space becoming stochastic is a process extremely rapid on the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Thus it is very valuable to be able to locate significant resonances and to predict the final particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we introduce a new method of determining domains of phase space in which good surfaces do not exist and use this method for quickly determining the final state of the particle distribution without carrying out the full time evolution leading to it.

  3. Modification of Ag nanoparticles on the surface of SrTiO3 particles and resultant influence on photoreduction of CO2

    Science.gov (United States)

    Shao, Kunjuan; Wang, Yanjie; Iqbal, Muzaffar; Lin, Lin; Wang, Kai; Zhang, Xuehua; He, Meng; He, Tao

    2018-03-01

    Modification of a wide-bandgap semiconductor with noble metals that can exhibit surface plasmon effect is an effective approach to make it responsive to the visible light. In this work, a series of cubic and all-edge-truncated SrTiO3 with and without thermal pretreatment in air are modified by Ag nanoparticles via photodeposition method. The crystal structure, morphology, loading amount of Ag nanoparticles, and optical properties of the obtained Ag-SrTiO3 nanomaterials are well characterized by powder X-ray diffraction, scanning microscope, transmission electron microscope, energy disperse X-ray spectroscopy, ICP-MS and UV-vis diffuse-reflection spectroscopy. The loading amount and size of the Ag nanoparticles can be controlled to some extent by tuning the photodeposition time via growth-dissolution mechanism. The Ag nanoparticles are inclined to deposit on different locations on the surface of cubic and truncated SrTiO3 with and without thermal pretreatment. The resultant SrTiO3 modified by Ag nanoparticles exhibits visible light activity for photocatalytic reduction of CO2, which is closely related to the oxygen vacancy induced by thermal pretreatment, size and amount of Ag nanoparticles. Accordingly, there is an optimized photodeposition time for the synthesis of the photocatalyst that exhibits the highest photocatalytic activity.

  4. Surface Modification of Catalytic Materials

    DEFF Research Database (Denmark)

    Nierhoff, Anders Ulrik Fregerslev

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

  5. Surface modification of recording electrodes

    Directory of Open Access Journals (Sweden)

    Iaci Miranda Pereira

    2013-01-01

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

  6. Nanofibrillated Cellulose Surface Modification: A Review

    Directory of Open Access Journals (Sweden)

    Julien Bras

    2013-05-01

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

  7. Modification of rubber surface by UV surface grafting

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  8. Surface Modification of Mg and Mg Alloys

    OpenAIRE

    Turhan, Can Metehan

    2012-01-01

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

  9. Excimer laser surface modification: Process and properties

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-12-01

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

  10. Surface Modifications in Adhesion and Wetting

    Science.gov (United States)

    Longley, Jonathan

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

  11. Modification of Plasma Solitons by Resonant Particles

    DEFF Research Database (Denmark)

    Karpman, Vladimir; Lynov, Jens-Peter; Michelsen, Poul

    1980-01-01

    A consistent theory of plasma soliton interaction with resonant particles is developed. A simple derivation of a perturbed Korteweg–de Vries equation with the interaction term is presented. It is shown how the known limit cases (such as Ott–Sudan’s, etc.) can be derived from the general equations...... Korteweg–de Vries equation. Laboratory measurements carried out in a strongly magnetized, plasma‐filled waveguide and results from particle simulation are interpreted in terms of the analytical results.......A consistent theory of plasma soliton interaction with resonant particles is developed. A simple derivation of a perturbed Korteweg–de Vries equation with the interaction term is presented. It is shown how the known limit cases (such as Ott–Sudan’s, etc.) can be derived from the general equations...... and what their regions of applicability are. Some effects caused by the soliton‐particle interaction (amplitude change‐rate, tail formation, etc.) are analyzed by means of a recently developed perturbation method. The analytical results are compared with a direct numerical integration of the perturbed...

  12. Influence of nanoclay particles modification by polyester-amide hyperbranched polymer on the corrosion protective performance of the epoxy nanocomposite

    International Nuclear Information System (INIS)

    Ganjaee Sari, M.; Ramezanzadeh, B.; Shahbazi, M.; Pakdel, A.S.

    2015-01-01

    Highlights: • Nanoclay particles were modified with polyester-amide hyperbranched polymer. • Epoxy/clay nanocomposites were prepared using modified clay particles. • Surface modification enhanced the clay particles exfoliation properties. • Surface modified clay particles enhanced corrosion resistance of the epoxy coating. - Abstract: Surface modification of nanoclay particles was carried out by various amounts of polyester-amide hyperbranched polymer (HBP). Thermal gravimetric analysis and X-ray diffraction analysis were performed to estimate the efficiency of the HPB grafting on the clay particles. Epoxy/clay nanocomposites were prepared by addition of 1 wt.% unmodified and modified clays. The corrosion protection properties of the nanocomposites were evaluated by electrochemical impedance spectroscopy (EIS). Results revealed that surface modification of the clay particles by HBP caused significant enhancement of the epoxy coating corrosion resistance especially when the ‘polymer/clay’ ratios were 10/1 and 5/1

  13. Tribological effects of polymer surface modification through plastic

    Indian Academy of Sciences (India)

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  16. Surface modification of polyethylene by plasma

    International Nuclear Information System (INIS)

    Colin O, E.

    2003-01-01

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

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

    National Research Council Canada - National Science Library

    Bystritskii, V

    1998-01-01

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

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

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

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

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

    Science.gov (United States)

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

    2017-12-01

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

  20. Surface modification of polyester biomaterials for tissue engineering

    International Nuclear Information System (INIS)

    Jiao Yanpeng; Cui Fuzhai

    2007-01-01

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

  1. MODIFICATION OF SURFACE KONDENSITSIONNYH AEROSOLS WELDING AND METALLURGICHESKIH PRODUCTIONS

    Directory of Open Access Journals (Sweden)

    A. A. Ennan

    2016-04-01

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

  2. Surface modification of ceramics. Ceramics no hyomen kaishitsu

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-07-05

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

  3. Surface modification and electrochemical behaviour of undoped nanodiamonds

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  4. Organic light emitting diode with surface modification layer

    Science.gov (United States)

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

    2017-09-12

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

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

    International Nuclear Information System (INIS)

    Cho, D.L.

    1986-01-01

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

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

    DEFF Research Database (Denmark)

    Rahimi, Maral; Fojan, Peter; Gurevich, Leonid

    2014-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

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

    Science.gov (United States)

    Kwok, Chi Tat

    1999-12-01

    because of the hardened surface which contained both martensite and retained austenite. Laser surface modification using NiCrSiB, AlSi, Si and C for enhancing the Re was also successfully accomplished. Intermetallic phases, borides and carbides were found to increase both the Re (4--10 times) and the hardness (2--3 times) of the laser treated S31603. The R e of S31603 laser surface modified with CoWC forming a metal-matrix composite (MMC) was highest (45.5 times) among all the materials studied. Laser surface modification with ceramics (e.g. WC and Cr2B) formed ceramic-matrix composite (CMC) but the Re was lower than that of the MMC because of rapid detaching of the ceramics particles from the specimens surface.

  9. Laser modification of macroscopic properties of metal surface layer

    Science.gov (United States)

    Kostrubiec, Franciszek

    1995-03-01

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

  10. LASER SURFACE MODIFICATION OF TITANIUM ALLOYS — A REVIEW

    OpenAIRE

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

    2005-01-01

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

  11. Comparison of several innovative bridge cable surface modifications

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos T.

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

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

    Science.gov (United States)

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

    2014-04-01

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

  13. Nanoparticle-Based Surface Modifications for Microtribology Control and Superhydrophobicity

    Science.gov (United States)

    Hurst, Kendall Matthew

    2010-11-01

    The emergence of miniaturization techniques for consumer electronics has brought forth the relatively new and exciting field of microelectromechanical systems (MEMS). However, due to the inherent forces that exist between surfaces at the micro- and nanoscale, scientists and semiconductor manufacturers are still struggling to improve the lifetime and reliability of complex microdevices. Due to the extremely large surface area-to-volume ratio of typical MEMS and microstructured surfaces, dominant interfacial forces exist which can be detrimental to their operational lifetime. In particular, van der Waals, capillary, and electrostatic forces contribute to the permanent adhesion, or stiction , of microfabricated surfaces. This strong adhesion force also contributes to the friction and wear of these silicon-based systems. The scope of this work was to examine the effect of utilizing nanoparticles as the basis for roughening surfaces for the purpose of creating films with anti-adhesive and/or superhydrophobic properties. All of the studies presented in this work are focused around a gas-expanded liquid (GXL) process that promotes the deposition of colloidal gold nanoparticles (AuNPs) into conformal thin films. The GXL particle deposition process is finalized by a critical point drying step which is advantageous to the microelectromechanical systems and semiconductor (IC) industries. In fact, preliminary results illustrated that the GXL particle deposition process can easily be integrated into current MEMS microfabrication processes. Thin films of AuNPs deposited onto the surfaces of silicon-based MEMS and tribology test devices were shown to have a dramatic effect on the adhesion of microstructures. In the various investigations, the apparent work of adhesion between surfaces was reduced by 2-4 orders of magnitude. This effect is greatly attributed to the roughening of the typically smooth silicon oxide surfaces which, in turn, dramatically decreases the "real are of

  14. Modification of polycarbonate surface in oxidizing plasma

    Science.gov (United States)

    Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

    2017-11-01

    The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

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

    Indian Academy of Sciences (India)

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

  16. Synthesis and surface modification of spindle-type magnetic nanoparticles: gold coating and PEG functionalization

    OpenAIRE

    Mendez-Garza , Juan; Wang , Biran; Madeira , Alexandra; Di-Giorgio , Christophe; Bossis , Georges

    2013-01-01

    International audience; In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles w...

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

    International Nuclear Information System (INIS)

    Feng Xiangfen; Xie Hankun; Zhang Jing

    2002-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Achala de Mel

    2012-01-01

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

  19. Surface modification of YIG by magnet array

    International Nuclear Information System (INIS)

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

    2015-01-01

    Highlights: • The surface of YIG films were magnetically modulated by magnet array. • The surface modulated YIG films formed sharp band gaps. • A very small magnetic field change leads a large change in the peak value of band gap frequency. - Abstract: In this work, magnetostatic surface spin waves (MSSW) were propagated along the single crystal YIG (Y_3Fe_5O_1_2) film grown on GGG substrate. In order to obtain magnonic crystals, unlike the conventional methods, the surface of YIG films were magnetically modulated by magnet array in one and two-dimensions. The surface modulated YIG films formed sharp band gaps at approximately 6.55 GHz and 6.58 GHz at 1600 Oe magnetic field for one and two-dimensional magnonic crystals, respectively. It was found that a very small magnetic field change leads a large change in the peak value of band gap frequency.

  20. Surface modification of YIG by magnet array

    Energy Technology Data Exchange (ETDEWEB)

    Atalay, S., E-mail: satalay@inonu.edu.tr [Inonu University, Science and Art Faculty, Physics Department, 44280 Malatya (Turkey); Kolat, V.S. [Inonu University, Science and Art Faculty, Physics Department, 44280 Malatya (Turkey); Bakır, H.G. [Inonu University, Science and Art Faculty, Astronomy Department, 44280 Malatya (Turkey); Izgi, T.; Kaya, A.O. [Inonu University, Science and Art Faculty, Physics Department, 44280 Malatya (Turkey); Kaya, O.A. [Inonu University, Education Faculty, Computer Education and Educational Technology Department, 44280 Malatya (Turkey); Gencer, H. [Inonu University, Science and Art Faculty, Physics Department, 44280 Malatya (Turkey)

    2015-11-01

    Highlights: • The surface of YIG films were magnetically modulated by magnet array. • The surface modulated YIG films formed sharp band gaps. • A very small magnetic field change leads a large change in the peak value of band gap frequency. - Abstract: In this work, magnetostatic surface spin waves (MSSW) were propagated along the single crystal YIG (Y{sub 3}Fe{sub 5}O{sub 12}) film grown on GGG substrate. In order to obtain magnonic crystals, unlike the conventional methods, the surface of YIG films were magnetically modulated by magnet array in one and two-dimensions. The surface modulated YIG films formed sharp band gaps at approximately 6.55 GHz and 6.58 GHz at 1600 Oe magnetic field for one and two-dimensional magnonic crystals, respectively. It was found that a very small magnetic field change leads a large change in the peak value of band gap frequency.

  1. Novel metal ion surface modification technique

    International Nuclear Information System (INIS)

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

    1990-10-01

    We describe a method for applying metal ions to the near-surface region of solid materials. The added species can be energetically implanted below the surface or built up as a surface film with an atomically mixed interface with the substrate; the metal ion species can be the same as the substrate species or different from it, and more than one kind of metal species can be applied, either simultaneously or sequentially. Surface structures can be fabricated, including coatings and thin films of single metals, tailored alloys, or metallic multilayers, and they can be implanted or added onto the surface and ion beam mixed. We report two simple demonstrations of the method: implantation of yttrium into a silicon substrate at a mean energy of 70 keV and a dose of 1 x 10 16 atoms/cm 2 , and the formation of a titanium-yttrium multilayer structure with ion beam mixing to the substrate. 17 refs., 3 figs

  2. Investigation of surface halide modification of nitrile butadiene rubber

    Science.gov (United States)

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

    2017-12-01

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

  3. Ion-induced surface modification of alloys

    International Nuclear Information System (INIS)

    Wiedersich, H.

    1983-11-01

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

  4. Surface modifications by field induced diffusion.

    Directory of Open Access Journals (Sweden)

    Martin Olsen

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

  5. Material surface modification for first wall protection

    International Nuclear Information System (INIS)

    Davis, M.J.

    1979-01-01

    The elements and strategy of a program to develop low Z surfaces for tokamak reactors is described. The development of low Z coated limiters is selected as an interim goal. Candidate materials were selected from the elements: Be, B, Al, Ti, V, C, O, N and their compounds. The effect of low energy erosion on surface morphology is shown for Be, TiC and VBe 12 . The tradeoffs in coating design are described. Stress analysis results for TiB 2 coated POCO graphite limiters for ORNL's ISX-B tokamak are given

  6. Surface modification of polyethylene films using atmospheric ...

    African Journals Online (AJOL)

    An atmospheric-pressure plasma jet (APPJ) is used to increase the wettability of polyethylene polymer films. Reduction in contact angle from 94.32 to 58.33 degrees was measured for treatment times of 1 - 5 seconds. Contact angle reductions of PE as a function of treatment time with APPJ and PE surface at various oxygen ...

  7. Surface Modification of Polyethylene Films using Atmospheric

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    An atmospheric-pressure plasma jet (APPJ) is used to increase the wettability of ... contact angle between the water droplet and the polymer surface. The polymer films used in this ... W of RF power from the generator. The distance between ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-01

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

  9. Steam Initiated Surface Modification of Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud

    The extensive demand of aluminium alloys in various industries such as in transportationis mainly due to the high strength to weight ratio, which could be translated into fuel economy and efficiency. Corrosion protection of aluminium alloys is an important aspect for all applications which includes...... the use of aluminium alloys in the painted form requiring a conversion coating to improve the adhesion. Chromate based conversion coating processes are extremely good for these purposes, however the carcinogenic and toxic nature of hexavalent chromium led to the search for more benign and eco......, crystalline nano-particles, role of steam-based treatment on adhesion of industrially applied powder coating, and investigations of a failed painted aluminium window profile due to defects in the extruded profile. Chapters 13 and 14 describe the overall discussion, conclusions and future work based...

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

    Science.gov (United States)

    Spalvins, T.

    1986-01-01

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

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

    Science.gov (United States)

    Spalvins, T.

    1987-01-01

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

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

    NARCIS (Netherlands)

    Maat, ter J.

    2012-01-01

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

  13. Surface modifications of aero-bearings

    International Nuclear Information System (INIS)

    Wang Yirong; Chen Jin; Nie Gao; Lu Haolin; Yang Qifa; Xu Qiu; Wang Peilu; Chen Yuanru; Liu Zhongyang

    1988-01-01

    Different ion beam techniques, i.e. ion beam mixing and ion implantation by either single or multi-element ions, were adopted to modify surface properties of aero-bearing samples that were made of GCr15 or Cr4Mo4V alloys, Results showed that corrosion behaviour and wear resistance of the samples treated with any of the techniques were improved significantly

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

    Directory of Open Access Journals (Sweden)

    YUCE Ismail

    2017-05-01

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

  15. Surface Modification of Metals using Plasma Torch

    International Nuclear Information System (INIS)

    Hassan, A.

    2009-01-01

    Low temperature plasma nitriding of 304L stainless steel is performed using a home made low power direct-current plasma torch. Plasma nitriding is carried out in temperature range of 300-550 degree C for 1 to 4 hours, in various N 2 H 2 gas mixture ratios at about 5 Torr pressure and torch power 300 Watts. The effect of treatment time, temperature and working gas composition on the microstructure and mechanical properties of plasma nitrided surface layers is investigated. The microstructure, phase composition and micro hardness profile of the nitrided surface layers are characterized by optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD) and Vickers micro hardness tester. The results show that plasma treatment for 14 h over a temperature range of 300 - 550 degree C yields nitride case depth of 20 - 50 μm and the hardness of the nitrided layer is in the range of 700-1250 HV. Plasma nitriding of stainless steel samples at about 475 degree C in 70 % of nitrogen admixed with hydrogen at 5 torr shows the maximum increase of hardness 1220 HV which is about four times that of untreated layers. The XRD pattern confirmed the formation of an expanded austenite .N phase, due to the nitrogen incorporation into original lattice and forms supersaturated face center cubic phase. In addition preliminary results for aluminum nitriding is also shown

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  17. Surface modification of titanium by plasma nitriding

    Directory of Open Access Journals (Sweden)

    Kapczinski Myriam Pereira

    2003-01-01

    Full Text Available A systematic investigation was undertaken on commercially pure titanium submitted to plasma nitriding. Thirteen different sets of operational parameters (nitriding time, sample temperature and plasma atmosphere were used. Surface analyses were performed using X-ray diffraction, nuclear reaction and scanning electron microscopy. Wear tests were done with stainless steel Gracey scaler, sonic apparatus and pin-on-disc machine. The obtained results indicate that the tribological performance can be improved for samples treated with the following conditions: nitriding time of 3 h; plasma atmosphere consisting of 80%N2+20%H2 or 20%N2+80%H2; sample temperature during nitriding of 600 or 800 degreesC.

  18. Surface modification of implants in long bone.

    Science.gov (United States)

    Förster, Yvonne; Rentsch, Claudia; Schneiders, Wolfgang; Bernhardt, Ricardo; Simon, Jan C; Worch, Hartmut; Rammelt, Stefan

    2012-01-01

    Coatings of orthopedic implants are investigated to improve the osteoinductive and osteoconductive properties of the implant surfaces and thus to enhance periimplant bone formation. By applying coatings that mimic the extracellular matrix a favorable environment for osteoblasts, osteoclasts and their progenitor cells is provided to promote early and strong fixation of implants. It is known that the early bone ongrowth increases primary implant fixation and reduces the risk of implant failure. This review presents an overview of coating titanium and hydroxyapatite implants with components of the extracellular matrix like collagen type I, chondroitin sulfate and RGD peptide in different small and large animal models. The influence of these components on cells, the inflammation process, new bone formation and bone/implant contact is summarized.

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

    Science.gov (United States)

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

    2010-05-01

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

  20. Surface modifications of polypropylene by high energy carbon ions

    International Nuclear Information System (INIS)

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

    2000-01-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  2. Surface modification of protein enhances encapsulation in chitosan nanoparticles

    Science.gov (United States)

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

    2018-04-01

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

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

    International Nuclear Information System (INIS)

    Miagava, J.; Gouvea, D.

    2011-01-01

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

  4. Irreversible adsorption of particles on heterogeneous surfaces.

    Science.gov (United States)

    Adamczyk, Zbigniew; Jaszczółt, Katarzyna; Michna, Aneta; Siwek, Barbara; Szyk-Warszyńska, Lilianna; Zembala, Maria

    2005-12-30

    Methods of theoretical and experimental evaluation of irreversible adsorption of particles, e.g., colloids and globular proteins at heterogeneous surfaces were reviewed. The theoretical models were based on the generalized random sequential adsorption (RSA) approach. Within the scope of these models, localized adsorption of particles occurring as a result of short-ranged attractive interactions with discrete adsorption sites was analyzed. Monte-Carlo type simulations performed according to this model enabled one to determine the initial flux, adsorption kinetics, jamming coverage and the structure of the particle monolayer as a function of the site coverage and the particle/site size ratio, denoted by lambda. It was revealed that the initial flux increased significantly with the site coverage theta(s) and the lambda parameter. This behavior was quantitatively interpreted in terms of the scaled particle theory. It also was demonstrated that particle adsorption kinetics and the jamming coverage increased significantly, at fixed site coverage, when the lambda parameter increased. Practically, for alpha = lambda2theta(s) > 1 the jamming coverage at the heterogeneous surfaces attained the value pertinent to continuous surfaces. The results obtained prove unequivocally that spherically shaped sites were more efficient in binding particles in comparison with disk-shaped sites. It also was predicted that for particle size ratio lambda charge. Particle deposition occurred under diffusion-controlled transport conditions and their coverage was evaluated by direct particle counting using the optical and electron microscopy. Adsorption kinetics was quantitatively interpreted in terms of numerical solutions of the governing diffusion equation with the non-linear boundary condition derived from Monte-Carlo simulations. It was proven that for site coverage as low as a few percent the initial flux at heterogeneous surfaces attained the maximum value pertinent to homogeneous

  5. Modification V to the computer code, STRETCH, for predicting coated-particle behavior

    International Nuclear Information System (INIS)

    Valentine, K.H.

    1975-04-01

    Several modifications have been made to the stress analysis code, STRETCH, in an attempt to improve agreement between the calculated and observed behavior of pyrocarbon-coated fuel particles during irradiation in a reactor environment. Specific areas of the code that have been modified are the neutron-induced densification model and the neutron-induced creep calculation. Also, the capability for modeling surface temperature variations has been added. HFIR Target experiments HT-12 through HT-15 have been simulated with the modified code, and the neutron-fluence vs particle-failure predictions compare favorably with the experimental results. Listings of the modified FORTRAN IV main source program and additional FORTRAN IV functions are provided along with instructions for supplying the additional input data. (U.S.)

  6. Hydrothermal modification and recycling of nonmetallic particles from waste print circuit boards.

    Science.gov (United States)

    Gao, Xuehua; Li, Qisheng; Qiu, Jun

    2018-04-01

    Nonmetallic particles recycled from waste print circuit boards (NPRPs) were modified by a hydrothermal treatment method and the catalysts, solvents, temperature and time were investigated, which affected the modification effect of NPRPs. The mild hydrothermal treatment method does not need high temperature, and would not cause secondary pollution. Further, the modified NPRPs were used as the raw materials for the epoxy resin and glass fibers/epoxy resin composites, which were prepared by pouring and hot-pressing method. The mechanical properties and morphology of the composites were discussed. The results showed that relative intensity of the hydroxyl bonds on the surface of NPRPs increased 58.9% after modification. The mechanical tests revealed that both flexural and impact properties of the composites can be significantly improved by adding the modified NPRPs. Particularly, the maximum increment of flexural strength, flexural modulus and impact strength of the epoxy matrix composites with 30% modified NPRPs is 40.1%, 80.0% and 79.0%, respectively. Hydrothermal treatment can modify surface of NPRPs successfully and modified NPRPs can not only improve the properties of the composites, but also reduce the production cost of the composites and environmental pollution. Thus, we develop a new way to recycle nonmetallic materials of waste print circuit boards and the highest level of waste material recycling with the raw materials-products-raw materials closed cycle can be realized through the hydrothermal modification and reuse of NPRPs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Research progress on laser surface modification of titanium alloys

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  8. Printing-assisted surface modifications of patterned ultrafiltration membranes

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

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

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

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Janda, Pavel; Weber, Jan

    2001-01-01

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

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

    Indian Academy of Sciences (India)

    Unknown

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

  12. Surface modification of polyethylene by diffuse barrier discharge plasma

    Czech Academy of Sciences Publication Activity Database

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

    2013-01-01

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

  13. Surface modification of magnetite nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Barrera, Carola; Herrera, Adriana; Zayas, Yashira; Rinaldi, Carlos

    2009-01-01

    The preparation of magnetite nanoparticles with narrow size distributions using poly(ethylene glycol) (PEG-COOH) or carboxymethyl dextran (CMDx) chains covalently attached to the particle surface using carbodiimide chemistry is described. Particles were synthesized by thermal decomposition and modified with 3-aminopropyl trimethoxysilane (APS) to render particles with reactive amine groups (-NH 2 ) on their surface. Amines were then reacted with carboxyl groups in PEG-COOH or CMDx using carbodiimide chemistry in water. The size and stability of the functionalized magnetic nanoparticles was studied as a function of pH and ionic strength using dynamic light scattering and zeta potential measurements.

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

    Directory of Open Access Journals (Sweden)

    E. Shirani

    2018-03-01

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

  15. Application of xenon difluoride for surface modification of polymers

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  16. Long-term stable surface modification of DLC coatings

    Directory of Open Access Journals (Sweden)

    Gotzmann Gaby

    2017-09-01

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

  17. Ion-Induced Surface Modification of Magnetically Operated Contacts

    Directory of Open Access Journals (Sweden)

    Karen Arushanov

    2012-02-01

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

  18. Modification of Surface Energy via Direct Laser Ablative Surface Patterning

    Science.gov (United States)

    Wohl, Christopher J., Jr. (Inventor); Belcher, Marcus A. (Inventor); Connell, John W. (Inventor); Hopkins, John W. (Inventor)

    2015-01-01

    Surface energy of a substrate is changed without the need for any template, mask, or additional coating medium applied to the substrate. At least one beam of energy directly ablates a substrate surface to form a predefined topographical pattern at the surface. Each beam of energy has a width of approximately 25 micrometers and an energy of approximately 1-500 microJoules. Features in the topographical pattern have a width of approximately 1-500 micrometers and a height of approximately 1.4-100 micrometers.

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

    Science.gov (United States)

    Song, Qing

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

  20. Surface modification on silicon with chitosan and biological research

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2005-12-01

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

  3. Benefits of aggregates surface modification in concrete production

    Science.gov (United States)

    Junak, J.; Sicakova, A.

    2017-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-04-15

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

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

    International Nuclear Information System (INIS)

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

    2007-04-01

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

  6. Surface Modification of Polymer Substrates for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Oldřich Neděla

    2017-09-01

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

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

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-11-14

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

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

    Science.gov (United States)

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

    2017-08-01

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

  9. Modification of homogeneous and isotropic turbulence by solid particles

    Science.gov (United States)

    Hwang, Wontae

    2005-12-01

    Particle-laden flows are prevalent in natural and industrial environments. Dilute loadings of small, heavy particles have been observed to attenuate the turbulence levels of the carrier-phase flow, up to 80% in some cases. We attempt to increase the physical understanding of this complex phenomenon by studying the interaction of solid particles with the most fundamental type of turbulence, which is homogeneous and isotropic with no mean flow. A flow facility was developed that could create air turbulence in a nearly-spherical chamber by means of synthetic jet actuators mounted on the corners. Loudspeakers were used as the actuators. Stationary turbulence and natural decaying turbulence were investigated using two-dimensional particle image velocimetry for the base flow qualification. Results indicated that the turbulence was fairly homogeneous throughout the measurement domain and very isotropic, with small mean flow. The particle-laden flow experiments were conducted in two different environments, the lab and in micro-gravity, to examine the effects of particle wakes and flow structure distortion caused by settling particles. The laboratory experiments showed that glass particles with diameters on the order of the turbulence Kolmogorov length scale attenuated the fluid turbulent kinetic energy (TKE) and dissipation rate with increasing particle mass loadings. The main source of fluid TKE production in the chamber was the speakers, but the loss of potential energy of the settling particles also resulted in a significant amount of production of extra TKE. The sink of TKE in the chamber was due to the ordinary fluid viscous dissipation and extra dissipation caused by particles. This extra dissipation could be divided into "unresolved" dissipation caused by local velocity disturbances in the vicinity of the small particles and dissipation caused by large-scale flow distortions from particle wakes and particle clusters. The micro-gravity experiments in NASA's KC-135

  10. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    International Nuclear Information System (INIS)

    Yuan, Yongbing; Chen, Hongling; Lin, Jinbin; Ji, Yan

    2013-01-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  11. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yongbing; Chen, Hongling, E-mail: hlchen@njut.edu.cn; Lin, Jinbin; Ji, Yan

    2013-11-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  12. Modifications of poly (vinilydene fluoride) under electronic excitations produced by charged particles (heavy ions and electrons)

    International Nuclear Information System (INIS)

    Fina, A.

    1990-04-01

    Some of the physico-chemical properties of organic solids like conductivity or permeation can be improved by irradiation. The aim of this work is to characterize modifications induced in poly (vinylidene fluoride) films (PVDF) by charged particles (ions and electrons), with electronic stopping power, for doses ranging from zero to twenty G-Grays. Influence of dose, density of electronic excitations, and flux (in particles per square centimeter), and the nature of defects induced by the beam, were studied with two methods: X-ray Photoelectron Spectroscopy (or XPS) for surface analysis, and electron Spin Resonance (or ESR) to probe the bulk of the film. Three ranges of doses are revealed in view of experimental results. At lower doses, PVDF undergoes deshydrofluorination induced by desorption; it is a low modifications regime. For intermediate range doses, conjugated carbon backbones of polyene compounds are produced. At higher doses, intermolecular interactions between the resulting fragments give a crosslinked network. For the upper limit of doses used, bond breaking results in a non reversible degradation of PVDF. In this last situation, direct atomic displacement of target atoms, is not negligible [fr

  13. Surface Friction of Polyacrylamide Hydrogel Particles

    Science.gov (United States)

    Cuccia, Nicholas; Burton, Justin

    Polyacrylamide hydrogel particles have recently become a popular system for modeling low-friction, granular materials near the jamming transition. Because a gel consists of a polymer network filled with solvent, its frictional behavior is often explained using a combination of hydrodynamic lubrication and polymer-surface interactions. As a result, the frictional coefficient can vary between 0.001 and 0.03 depending on several factors such as contact area, sliding velocity, normal force, and the gel surface chemistry. Most tribological measurements of hydrogels utilize two flat surfaces, where the contact area is not well-defined. We have built a custom, low-force tribometer to measure the single-contact frictional properties of spherical hydrogel particles on flat hydrogel surfaces under a variety of measurement conditions. At high velocities (> 1 cm/s), the friction coefficient depends linearly on velocity, but does not tend to zero at zero velocity. We also compare our measurements to solid particles (steel, glass, etc.) on hydrogel surfaces, which exhibit larger frictional forces, and show less dependence on velocity. A physical model for the friction which includes the lubrication layer between the deformed surfaces will be discussed. National Science Foundation Grant No. 1506446.

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

    Science.gov (United States)

    Torres, Jessica

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

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-01

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

  17. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

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

  18. Surface Topographical Modification of Coronary Stent: A Review

    Science.gov (United States)

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

    2017-06-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

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

    Science.gov (United States)

    Feng, Qicheng; Zhao, Wenjuan; Wen, Shuming

    2018-04-01

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

  1. Surface modification of zinc oxide nanoparticle by PMAA and its dispersion in aqueous system

    Energy Technology Data Exchange (ETDEWEB)

    Tang Erjun [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang Hebei 050018 (China); Cheng Guoxiang [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)]. E-mail: gxcheng@tju.edu.cn; Ma Xiaolu [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Pang Xingshou [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhao Qiang [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2006-05-15

    Commercial zinc oxide nanoparticles were modified by polymethacrylic acid (PMAA) in aqueous system. The hydroxyl groups of nano-ZnO particle surface can interact with carboxyl groups (COO-) of PMAA and form poly(zinc methacrylate) complex on the surface of nano-ZnO. The formation of poly(zinc methacrylate) complex was testified by Fourier-transform infrared spectra (FT-IR). Thermogravimetric analysis (TGA) indicated that PMAA molecules were absorbed or anchored on the surface of nano-ZnO particle, which facilitated to hinder the aggregation of nano-ZnO particles. Through particle size analysis and transmission electron micrograph (TEM) observation, it was found that PMAA enhanced the dispersibility of nano-ZnO particles in water. The dispersion stabilization of modified ZnO nanoparticles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nanoparticles. The modification did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns.

  2. Surface modification of zinc oxide nanoparticle by PMAA and its dispersion in aqueous system

    Science.gov (United States)

    Tang, Erjun; Cheng, Guoxiang; Ma, Xiaolu; Pang, Xingshou; Zhao, Qiang

    2006-05-01

    Commercial zinc oxide nanoparticles were modified by polymethacrylic acid (PMAA) in aqueous system. The hydroxyl groups of nano-ZnO particle surface can interact with carboxyl groups (COO-) of PMAA and form poly(zinc methacrylate) complex on the surface of nano-ZnO. The formation of poly(zinc methacrylate) complex was testified by Fourier-transform infrared spectra (FT-IR). Thermogravimetric analysis (TGA) indicated that PMAA molecules were absorbed or anchored on the surface of nano-ZnO particle, which facilitated to hinder the aggregation of nano-ZnO particles. Through particle size analysis and transmission electron micrograph (TEM) observation, it was found that PMAA enhanced the dispersibility of nano-ZnO particles in water. The dispersion stabilization of modified ZnO nanoparticles in aqueous system was significantly improved due to the introduction of grafted polymer on the surface of nanoparticles. The modification did not alter the crystalline structure of the ZnO nanoparticles according to the X-ray diffraction patterns.

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

    Science.gov (United States)

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

    2017-10-01

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

  4. Surface Modification of Magnetic Nanoparticles Using Gum Arabic

    International Nuclear Information System (INIS)

    Williams, Darryl N.; Gold, Katie A.; Holoman, Tracey R. Pulliam; Ehrman, Sheryl H.; Wilson, Otto C.

    2006-01-01

    Magnetite nanoparticles were synthesized and functionalized by coating the particle surfaces with gum arabic (GA) to improve particle stability in aqueous suspensions (i.e. biological media). Particle characterization was performed using transmission electron microscopy (TEM) and dynamic light scattering (DLS) to analyze the morphology and quantify the size distribution of the nanoparticles, respectively. The results from DLS indicated that the GA-treated nanoparticles formed smaller agglomerates as compared to the untreated samples over a 30-h time frame. Thermogravimetric analyses indicated an average weight loss of 23%, showing that GA has a strong affinity toward the iron oxide surface. GA most likely contributes to colloid stability via steric stabilization. It was determined that the adsorption of GA onto magnetite exhibits Langmuir behavior

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  7. Surface modification of fluorocarbon polymers by synchrotron radiation

    CERN Document Server

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

    2003-01-01

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

  8. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-01-01

    This research aims to add to the current knowledge available for miniemulsion polymerization reactions and to use this knowledge to synthesize multifunctional nanosized latex particles that have the potential to be used in catalysis. The physical

  9. On a modification of the Newtonian particle view of rays

    International Nuclear Information System (INIS)

    Ben-Benjamin, J S; Cohen, L

    2015-01-01

    We have developed a simple Newtonian dynamics for the motion of rays as particles that are governed by Snell’s law. In Newton’s original formulation, the particle moves faster in a relatively higher index of refraction medium. We show that it is the constant mass assumption that leads to this conclusion. We derive an explicit expression for the mass as a function of position and show that the formulation leads to the conclusion that indeed the particle moves slower in a relatively higher index of refraction medium. Our approach leads to a simple Newtonian particle picture where the equations of motion may be simply written. We obtain explicit expressions for the velocity, acceleration, and forces which allow one to write the equations of motion. We also formulate the dynamics in terms of the Lagrangian and Hamiltonian formulations, taking variable mass into account. The solutions to the dynamics are such that the particle always follows Snell’s law in a variable index of refraction medium. Exactly solvable analytic examples are given. We also we show that the SOFAR channel phenomenon, where a wave is trapped between two regions, is easily explained in the particle picture. (invited comment)

  10. Fabrication and surface properties of hydrophobic barium sulfate aggregates based on sodium cocoate modification

    Science.gov (United States)

    Hu, Linna; Wang, Guangxiu; Cao, Rong; Yang, Chun; Chen, Xi

    2014-10-01

    Hydrophobic barium sulfate aggregates were fabricated by the direction of cocoate anions. At 30 °C, when the weight ratio of sodium cocoate to BaSO4 particles was 2.0 wt.%, the active ratio of the product reached 99.43% and the contact angle was greater than 120°. This method could not only simplify the complex modification process, but reduce energy consumption. The surface morphology, chemical structure and composition of BaSO4 aggregates were characterized by SEM, XRD, and FTIR. The results indicated that the as-synthesized BaSO4 particles were almond-liked and were composed of many interconnected nanoballs and that their surfaces were affected by cocoate anions. The adsorption of cocoate anions reversed the charge and weakened the surface polarity of BaSO4 particles, driving the formation of aggregates. And cocoate anions induced a change of the BaSO4 particles surface from hydrophilic to hydrophobic by a self-assembly and transformation process. Due to the self-assembled structure and the surface hydrophobicity, when adding the hydrophobic BaSO4 into PVC, the mechanical properties of PVC composite materials were significantly improved.

  11. Surface crack detection by magnetic particle inspection

    International Nuclear Information System (INIS)

    Goebbels, K.

    1988-01-01

    For ferromagnetic materials magnetic particle inspection is without doubt the most sensitive method to detect surface cracks and the least sensitive method referring to disturbing boundary conditions. Up to now the technique is based on experiments, experience, on empirical facts and on a subjective evaluation. This contribution for the first time presents a concept which allows the objective, reproducible as well as reliable magnetic particle inspection: Modelling of testing based on Maxwell's equations by finite element calculation; objective setting of test-parameters and their surveillance, handling systems, illumination and sensors, image processing and fully automated evaluation. Economy and safety of magnetic particle inspection are strongly improved by this procedure. (orig./HP) [de

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

    Science.gov (United States)

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

    2010-11-01

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

  13. Silane surface modification for improved bioadhesion of esophageal stents

    Science.gov (United States)

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

    2014-08-01

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

  14. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    International Nuclear Information System (INIS)

    Sodipo, Bashiru Kayode; Aziz, Azlan Abdul

    2016-01-01

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

  15. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    Energy Technology Data Exchange (ETDEWEB)

    Sodipo, Bashiru Kayode, E-mail: bashirsodipo@gmail.com [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Pulau Pinang (Malaysia)

    2016-10-15

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION. - Highlights: • We present recent advances in synthesis of SPION and various routes of producing silica coated SPION • The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods. • The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase. • The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  17. Modification of Au surfaces using new ferrocene derivatives

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  18. Laser surface modification of boronickelized medium carbon steel

    Science.gov (United States)

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

    2015-11-01

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

  19. Surface modifications of magnesium alloys for biomedical applications.

    Science.gov (United States)

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

    2011-07-01

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

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

    Directory of Open Access Journals (Sweden)

    R. Arvind Singh

    2011-12-01

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

  1. Medical applications of diamond particles & surfaces

    OpenAIRE

    Roger J Narayan; Ryan D. Boehm; Anirudha V. Sumant

    2011-01-01

    Diamond has been considered for use in several medical applications due to its unique mechanical, chemical, optical, and biological properties. In this paper, methods for preparing synthetic diamond surfaces and particles are described. In addition, recent developments involving the use of diamond in prostheses, sensing, imaging, and drug delivery applications are reviewed. These developments suggest that diamond-containing structures will provide significant improvements in the diagnosis and...

  2. Surface Modification of Polymeric Materials by Plasma Treatment

    Directory of Open Access Journals (Sweden)

    E.F. Castro Vidaurre

    2002-03-01

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

  3. Surface modification of multilayer graphene using Ga ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-28

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2005-11-01

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

  6. Synergistic effects in radiation-induced particle ejection from solid surfaces

    International Nuclear Information System (INIS)

    Itoh, Noriaki

    1990-01-01

    A description is given on radiation-induced particle ejection from solid surfaces, emphasizing synergistic effects arising from multi-species particle irradiation and from irradiation under complex environments. First, it is pointed out that synergisms can be treated by introducing the effects of material modification on radiation-induced particle ejection. As examples of the effects of surface modification on the sputtering induced by elastic encounters, sputtering of alloys and chemical sputtering of graphite are briefly discussed. Then the particle ejection induced by electronic encounters is explained emphasizing the difference in the behaviors from materials to materials. The possible synergistic effects of electronic and elastic encounters are also described. Lastly, we point out the importance of understanding the elementary processes of material-particle interaction and of developing computer codes describing material behaviors under irradiation. (author)

  7. Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hak-Sung Jung

    2012-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  9. Surface modification by EUV laser beam based on capillary discharge

    Czech Academy of Sciences Publication Activity Database

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

    -, č. 58 (2011), s. 484-487 ISSN 2010-376X. [International Conference on Fusion and Plasma Physics. Bali, Indonésie, 26.10.2011-28.10.2011] R&D Projects: GA AV ČR KAN300100702; GA MŠk LA08024; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508 Keywords : soft x-ray * EUV * laser * radiation * source * capillary * discharge * plasma * ablation * surface modification Subject RIV: BL - Plasma and Gas Discharge Physics http://www.waset.org/journals/waset/v58/v58-99.pdf

  10. Application of MEVVA discharge to material surface modification

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  11. Surface modification of yttria stabilized zirconia by ion implantation

    International Nuclear Information System (INIS)

    Scholten, D.

    1987-01-01

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

  12. 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.

  13. 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.

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

    Science.gov (United States)

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

    2017-07-21

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

  15. Kinetics of particle deposition at heterogeneous surfaces

    Science.gov (United States)

    Stojiljković, D. Lj.; Vrhovac, S. B.

    2017-12-01

    The random sequential adsorption (RSA) approach is used to analyze adsorption of spherical particles of fixed diameter d0 on nonuniform surfaces covered by square cells arranged in a square lattice pattern. To characterize such pattern two dimensionless parameters are used: the cell size α and the cell-cell separation β, measured in terms of the particle diameter d0. Adsorption is assumed to occur if the particle (projected) center lies within a cell area. We focus on the kinetics of deposition process in the case when no more than a single disk can be placed onto any square cell (α deposition process is not consistent with the power law behavior. However, if the geometry of the pattern approaches towards ;noninteracting conditions; (β > 1), when adsorption on each cell can be decoupled, approach of the coverage fraction θ(t) to θJ becomes closer to the exponential law. Consequently, changing the pattern parameters in the present model allows to interpolate the deposition kinetics between the continuum limit and the lattice-like behavior. Structural properties of the jammed-state coverings are studied in terms of the radial distribution function g(r) and spatial distribution of particles inside the cell. Various, non-trivial spatial distributions are observed depending on the geometry of the pattern.

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

    International Nuclear Information System (INIS)

    Brown, Angela Ann

    1998-01-01

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

  17. Science and engineering of nanodiamond particle surfaces for biological applications (Review).

    Science.gov (United States)

    Shenderova, Olga A; McGuire, Gary E

    2015-09-05

    Diamond has outstanding bulk properties such as super hardness, chemical inertness, biocompatibility, luminescence, to name just a few. In the nanoworld, in order to exploit these outstanding bulk properties, the surfaces of nanodiamond (ND) particles must be accordingly engineered for specific applications. Modification of functional groups on the ND's surface and the corresponding electrostatic properties determine their colloidal stability in solvents, formation of photonic crystals, controlled adsorption and release of cargo molecules, conjugation with biomolecules and polymers, and cellular uptake. The optical activity of the luminescent color centers in NDs depends on their proximity to the ND's surface and surface termination. In order to engineer the ND surface, a fundamental understanding of the specific structural features and sp(3)-sp(2) phase transformations on the surface of ND particles is required. In the case of ND particles produced by detonation of carbon containing explosives (detonation ND), it should also be taken into account that its structure depends on the synthesis parameters and subsequent processing. Thus, for development of a strategy of surface modification of detonation ND, it is imperative to know details of its production. In this review, the authors discuss ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and conclude with a brief overview of the relevant bioapplications.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  19. Surface Modifications of Support Partitions for Stabilizing Biomimetic Membrane Arrays

    DEFF Research Database (Denmark)

    Perry, Mark; Hansen, Jesper Schmidt; Jensen, Karin Bagger Stibius

    2011-01-01

    with a high signal-to-noise (s/n) ratio. We demonstratesd this by reconstituting gA and α-hemolysin (α-HL) into BLM arrays. The improvement in membrane array lifetime and s/n ratio demonstrates that surface plasma polymerization of the supporting partition can be used to increase the stability of biomimetic......Black lipid membrane (BLM) formation across apertures in an ethylene tetra-fluoroethylene (ETFE) partition separating two aqueous compartments is an established technique for the creation of biomimetic membranes. Recently multi-aperture BLM arrays have attracted interest and in order to increase...... BLM array stability we studied the effect of covalently modifying the partition substrate using surface plasma polymerization with hydrophobic n-hexene, 1-decene and hexamethyldisiloxane (HMDSO) as modification groups. Average lifetimes across singlesided HMDSO modified partitions or using 1-decene...

  20. Carbon ion irradiation induced surface modification of polypropylene

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  1. Carbon ion irradiation induced surface modification of polypropylene

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-01

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

  2. Plasma immersion surface modification with metal ion plasma

    International Nuclear Information System (INIS)

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

    1991-04-01

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

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

    Science.gov (United States)

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

    2014-05-28

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

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

    Science.gov (United States)

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

    2014-06-25

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

  5. Surface modification of biomaterials and biomedical devices using additive manufacturing.

    Science.gov (United States)

    Bose, Susmita; Robertson, Samuel Ford; Bandyopadhyay, Amit

    2018-01-15

    The demand for synthetic biomaterials in medical devices, pharmaceutical products and, tissue replacement applications are growing steadily due to aging population worldwide. The use for patient matched devices is also increasing due to availability and integration of new technologies. Applications of additive manufacturing (AM) or 3D printing (3DP) in biomaterials have also increased significantly over the past decade towards traditional as well as innovative next generation Class I, II and III devices. In this review, we have focused our attention towards the use of AM in surface modified biomaterials to enhance their in vitro and in vivo performances. Specifically, we have discussed the use of AM to deliberately modify the surfaces of different classes of biomaterials with spatial specificity in a single manufacturing process as well as commented on the future outlook towards surface modification using AM. It is widely understood that the success of implanted medical devices depends largely on favorable material-tissue interactions. Additive manufacturing has gained traction as a viable and unique approach to engineered biomaterials, for both bulk and surface properties that improve implant outcomes. This review explores how additive manufacturing techniques have been and can be used to augment the surfaces of biomedical devices for direct clinical applications. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-01-01

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

  7. Surface Modification of Electrospun PVDF/PAN Nanofibrous Layers by Low Vacuum Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2016-01-01

    Full Text Available Nanofibres are very promising for water remediation due to their high porosity and small pore size. Mechanical properties of nanofibres restrict the application of pressure needed water treatments. Various PAN, PVDF, and PVDF/PAN nanofibre layers were produced, and mechanical properties were improved via a lamination process. Low vacuum plasma treatment was applied for the surface modification of nanofibres. Atmospheric air was used to improve hydrophilicity while sulphur hexafluoride gas was used to improve hydrophobicity of membranes. Hydrophilic membranes showed higher affinity to attach plasma particles compared to hydrophobic membranes.

  8. An inexpensive particle monitor for smoker behaviour modification in homes.

    Science.gov (United States)

    Semple, Sean; Apsley, Andrew; Maccalman, Laura

    2013-09-01

    To compare the response of a new particle counting instrument (Dylos DC1700) with that produced by a device (TSI Sidepak Personal Aerosol Monitor AM510) commonly used to measure PM2.5 in settings where secondhand smoke (SHS) is encountered. Controlled chamber experiments with different SHS concentrations were generated by burning a cigarette for varying time periods and running both devices simultaneously. The Dylos and Sidepak devices produced similar responses to changes in SHS concentrations up to 1000 μg/m(3). Using 591 min of contemporaneous measurements from 13 chamber experiments, an equation was developed to allow conversion of particle number concentration data from the Dylos to estimated mass concentration data for SHS aerosol. The Dylos DC1700 can provide real-time data that may be converted to an estimate of SHS levels in smoky environments. Given the low cost, low noise and simplicity of use, this device is likely to be a useful tool for interventions to provide feedback of SHS concentrations to help motivate changes in smoking behaviour at home.

  9. Surface modification of cellulose isolated from Sesamun indicum underutilized seed: A means of enhancing cellulose hydrophobicity

    Directory of Open Access Journals (Sweden)

    Adewale Adewuyi

    2017-09-01

    Full Text Available Cellulose (SC isolated from sesame seed (SS was surface modified with the introduction of an ester functional group via a simple reaction to produce the modified product (SA. SS, SC and SA were characterized using Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TG, particle size distribution (PSD, zeta potential and scanning electron microscopy (SEM. SC and SA were evaluated for their water holding capacity (WC, oil holding capacity (OC, swelling capacity (SW and their ability to adsorb heavy metals. The FTIR revealed peaks corresponding to the formation of the ester functional group at the surface of SA. The crystallinity of SC was 28.02% but after the modification, it increased to 77.03% in SA. The PSD of SC and SA was both monomodal with sizes of 10.1305 μm in SC and 10.2511 μm in SA. The adsorption capacity of SC towards Pb (II and Cu (II ions was higher than that of SA. However, SA was unable to adsorb Cu (II ions. SA exhibited the lower WC and SW values as compared to SC which suggested an improved hydrophobicity after the modification. This study has shown that hydrophobicity can be improved in cellulose via surface modification.

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

    Science.gov (United States)

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

    2011-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

  13. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-05-01

    This research aims to add to the current knowledge available for miniemulsion polymerization reactions and to use this knowledge to synthesize multifunctional nanosized latex particles that have the potential to be used in catalysis. The physical properties of the latex can be adjusted to suit various environments due to the multiple functional groups present. For this research, styrene, pentafluorostyrene, azidomethyl styrene, pentafluorostyrene with azidomethyl styrene and pentafluorostyrene with styrene latexes were produced, and analyzed by dynamic light scattering. The latexes were synthesized using a miniemulsion polymerization technique found through this research. Potassium oleate and potassium 1,1,2,2,3,3,4,4-nonafluorobutane-1-sulfonate were used as surfactants during the miniemulsion polymerization reaction to synthesize pentafluorostyrene with azidomethyl styrene latex. Transmission electron microscopy data and dynamic light scattering data have been collected to analyze the structure of this latex, and it has been synthesized using a number of conditions, differing in reaction time, surfactant amount and sonication methods. We have also improved the solubility of the latex through a copper(I) catalyzed 1,3-dipolar azide-alkyne reaction, by clicking (polyethylene glycol)5000 onto the azide functional groups.

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

    DEFF Research Database (Denmark)

    Hoffmann, Christian

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

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

    International Nuclear Information System (INIS)

    Lu, Z X

    2013-01-01

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

  16. Design of sustained release fine particles using two-step mechanical powder processing: particle shape modification of drug crystals and dry particle coating with polymer nanoparticle agglomerate.

    Science.gov (United States)

    Kondo, Keita; Ito, Natsuki; Niwa, Toshiyuki; Danjo, Kazumi

    2013-09-10

    We attempted to prepare sustained release fine particles using a two-step mechanical powder processing method; particle-shape modification and dry particle coating. First, particle shape of bulk drug was modified by mechanical treatment to yield drug crystals suitable for the coating process. Drug crystals became more rounded with increasing rotation speed, which demonstrates that powerful mechanical stress yields spherical drug crystals with narrow size distribution. This process is the result of destruction, granulation and refinement of drug crystals. Second, the modified drug particles and polymer coating powder were mechanically treated to prepare composite particles. Polymer nanoparticle agglomerate obtained by drying poly(meth)acrylate aqueous dispersion was used as a coating powder. The porous nanoparticle agglomerate has superior coating performance, because it is completely deagglomerated under mechanical stress to form fine fragments that act as guest particles. As a result, spherical drug crystals treated with porous agglomerate were effectively coated by poly(meth)acrylate powder, showing sustained release after curing. From these findings, particle-shape modification of drug crystals and dry particle coating with nanoparticle agglomerate using a mechanical powder processor is expected as an innovative technique for preparing controlled-release coated particles having high drug content and size smaller than 100 μm. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Abednejad, Atiye Sadat, E-mail: atiyeabednejad@gmail.com [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Research Center for New Technologies in Life Science Engineering, University of Tehran, P.O. Box 63894-14179, Tehran (Iran, Islamic Republic of); Ghaee, Azadeh [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of)

    2014-09-01

    Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H{sub 2} and O{sub 2} plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H{sub 2} and O{sub 2} plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion.

  18. Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Guo Xiaojun, E-mail: guoxj6906@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China); Zhao Leihua; Zhang Li; Li Jing [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China)

    2012-01-15

    Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108 Degree-Sign and a well dispersion.

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

    Directory of Open Access Journals (Sweden)

    Wiśniewska-Weinert H.

    2015-09-01

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

  20. Self-assembling triblock proteins for biofunctional surface modification

    Science.gov (United States)

    Fischer, Stephen E.

    of the triblock protein hydrogels, and the ease of introducing multiple functionalities to a substrate surface, a surface coating is tailored for neural stem cell culture in order to improve proliferation on the scaffold, while maintaining the stem cell phenotype. These studies demonstrate the unique advantages of genetic engineering over traditional techniques for surface modification. In addition to their unmatched sequence fidelity, recombinant proteins can easily be modified with bioactive ligands and their organization into coherent, supramolecular structures mimics natural self-assembly processes.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  2. [Preparation and catalytic activity of surface-modification CNTs/TiO2 composite photocatalysts].

    Science.gov (United States)

    Wang, Huan-Ying; Li, Wen-Jun; Chang, Zhi-Dong; Zhou, Hua-Lei; Guo, Hui-Chao

    2011-09-01

    A novel kind of carbon nanotubes/titanium dioxide (CNTs/TiO2) composite photocatalyst was prepared by a modified sol-gel method in which the nanoscaled TiO2 particles were uniformly deposited on the CNTs modified with poly(vinyl pyrrolidone) (PVP). The composites were characterized by a range of analytical techniques including high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show the successful covering of the CNTs with PVP, forming core-shell structure. The nanoscaled TiO2 particles were uniformly deposited on the surface of CNTs reducing the bare CNTs which avoid losing the absorption and scattering of photons. The combination of CNTs and TiO2 particles imply the enhanced interactions between the CNTs and TiO2 interface which possibly becomes heterojunction. The composites become mesoporous crystalline TiO2 (anatase) clusters after annealing at 500 degrees C, and the surface area increases obviously. The photocatalytic activities of surface modification CNTs/TiO2 (smCNTs/TiO2) composites are extremely enhanced from the results of the photodegradation of methylene blue (MB).

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

    Science.gov (United States)

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

    2011-01-01

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

  4. PREFACE Surface Modifications of Diamond and Related Materials (Session D, E-MRS Spring Meeting)

    Science.gov (United States)

    Nebel, Christoph E.

    2010-11-01

    This special issue contains selected papers which were presented at the E-MRS Symposium BIOMATERIALS, SENSORS & SURFACES, D: 'Surface modifications of diamond and related materials' which was held on 7-9 June 2010 in Strasbourg (France). With about 54 oral and poster presentations given from teams all over the world it was a very interesting, dense and lively meeting. The symposium focused on chemical modifications applied to graft surfaces of diamond, nano-diamond particles, diamond-like carbon, graphene, graphite and carbon nano-tubes with linker molecular layers for realization of bio-sensors, bio-markers, separation techniques, and switchable chemical links. Presented techniques span spontaneous bonding to photo-chemical attachment, electrochemical modifications, to Suzuki-coupling of aryl molecules. Special attention was drawn to mechanisms driving bonding kinetics such as electron transfer reactions, hydrogen cleavage reactions by nucleophilic molecules and growths schemas which vary from correlated two-dimensional chain reactions to three-dimensional cross polymerization. Hydrogen terminations, surface defects, surface roughness and atomic arrangements of surface carbon atoms were of interest to elucidate bonding mechanisms. In addition, bonding stability, either of linker molecules or of complex functionalized surfaces with DNA, proteins and enzymes was discussed by several speakers as well as details of the electronic interfaces between solid transducers and bio-layers. Here the characterization of surface and interface defect densities, of Fermi level pinning and of electron transfer rates was a major topic. Miniaturization of sensor area and application of new detection schemas was discussed. Diamond nano-particles which are increasingly used as biomarkers in drug delivery experiments also attracted attention. The organizers express our gratitude to the international members of the scientific committee who actively contributed to ensure an attractive

  5. Crack path and fracture surface modifications in cement composites

    Directory of Open Access Journals (Sweden)

    Sajjad Ahmad

    2015-10-01

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

  6. Surface functionalized hollow silica particles and composites

    KAUST Repository

    Rodionov, Valentin; Khanh, Vu Bao

    2017-01-01

    Composition comprising hollow spherical silica particles having outside particle walls and inside particle walls, wherein the particles have an average particle size of about 10 nm to about 500 nm and an average wall thickness of about 10 nm to about 50 nm; and wherein the particles are functionalized with at least one organic functional group on the outside particle wall, on the inside particle wall, or on both the outside and inside particle walls, wherein the organic functional group is in a reacted or unreacted form. The organic functional group can be epoxy. The particles can be mixed with polymer precursor or a polymer material such as epoxy to form a prepreg or a nanocomposite. Lightweight but strong materials can be formed. Low loadings of hollow particles can be used.

  7. Surface functionalized hollow silica particles and composites

    KAUST Repository

    Rodionov, Valentin

    2017-05-26

    Composition comprising hollow spherical silica particles having outside particle walls and inside particle walls, wherein the particles have an average particle size of about 10 nm to about 500 nm and an average wall thickness of about 10 nm to about 50 nm; and wherein the particles are functionalized with at least one organic functional group on the outside particle wall, on the inside particle wall, or on both the outside and inside particle walls, wherein the organic functional group is in a reacted or unreacted form. The organic functional group can be epoxy. The particles can be mixed with polymer precursor or a polymer material such as epoxy to form a prepreg or a nanocomposite. Lightweight but strong materials can be formed. Low loadings of hollow particles can be used.

  8. Roman sophisticated surface modification methods to manufacture silver counterfeited coins

    Science.gov (United States)

    Ingo, G. M.; Riccucci, C.; Faraldi, F.; Pascucci, M.; Messina, E.; Fierro, G.; Di Carlo, G.

    2017-11-01

    By means of the combined use of X-ray photoelectron spectroscopy (XPS), optical microscopy (OM) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) the surface and subsurface chemical and metallurgical features of silver counterfeited Roman Republican coins are investigated to decipher some aspects of the manufacturing methods and to evaluate the technological ability of the Roman metallurgists to produce thin silver coatings. The results demonstrate that over 2000 ago important advances in the technology of thin layer deposition on metal substrates were attained by Romans. The ancient metallurgists produced counterfeited coins by combining sophisticated micro-plating methods and tailored surface chemical modification based on the mercury-silvering process. The results reveal that Romans were able systematically to chemically and metallurgically manipulate alloys at a micro scale to produce adherent precious metal layers with a uniform thickness up to few micrometers. The results converge to reveal that the production of forgeries was aimed firstly to save expensive metals as much as possible allowing profitable large-scale production at a lower cost. The driving forces could have been a lack of precious metals, an unexpected need to circulate coins for trade and/or a combinations of social, political and economic factors that requested a change in money supply. Finally, some information on corrosion products have been achieved useful to select materials and methods for the conservation of these important witnesses of technology and economy.

  9. Surface modification of iron oxide nanoparticles and their conjuntion with water soluble polymers for biomedical application

    International Nuclear Information System (INIS)

    Nguyen Thanh Huong; Lam Thi Kieu Giang; Nguyen Thanh Binh; Le Quoc Minh

    2009-01-01

    Superparamagnetic iron oxide nanoparticles (SPION) coated with suitable bio-compatible substances have been used in biomedicine, particularly in magnetic resonance imaging (MRI), tissue engineering, and hyperthermia and drug delivery. In this study, we describe the synthesis of SPION and its surface modification for in-vitro experiments. The particle diameter and structure were estimated by FESEM, TEM, XRD analyses. The saturation magnetization was characterized. SPION with a mean size of 12 nm have been prepared under N 2 atmosphere, with support of natural polymeric starch, by controlling chemical coprecipitation of magnetite phase from aqueous solutions containing suitable salts ratios of Fe 2+ and Fe 3+ . The surface of SPION-nanoparticles was treated with a coordinatable agent for higher dispersion ability in water and remaining the superparamagnetic behavior. The prepared iron oxide nanoparticles were coated with starch, dextran, PEG or MPEG to extend the application potential in the quite different engineering field of nano biomedicine.

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

    International Nuclear Information System (INIS)

    Fan, X.; Rowson, N.A.

    2002-01-01

    The main problems with ilmenite flotation in impeller-type flotation machines are the poor flotation behaviour of ilmenite and the negative effect of slimes. These cause high ilmenite losses in tailings even when a large dosage of fatty acid and fuel oil is consumed. In this study, microwave radiation pre-treatment and ilmenite surface activation were used to modify the surface properties of a massive ilmenite ore sample from Norway to improve ilmenite flotability. A column cell was used to minimize the negative effect of slimes on ilmenite separation efficiency. When ilmenite flotation was performed in a 1 litre Denver cell, the flotation recovery of titanium dioxide from the ilmenite ore sample was only 68.5% (31.1% TiO 2 ) under conventional flotation conditions. After microwave radiation pre-treatment for three minutes at 2600 W and 2.45 GHz, the ferrous ions on ilmenite particle surfaces were converted into ferric ions; hence, the recovery increased from 68.5% to 86.8%. The concentrate grade increased from 31.1% TiO 2 to 32.1% TiO 2 . In ilmenite activation flotation, Pb 2+ ions can be selectively adsorbed on to ilmenite particle surfaces as active sites and therefore enhance the adsorption of oleate ions on ilmenite surfaces. With the addition of 60 g/ton Pb(NO 3 ) 2 , ilmenite flotation recovery increased from 68.5% to 85.1%. However, the quality of ilmenite concentrates was not improved due to the negative effect of slimes. After a two stage cleaning, the grade of ilmenite concentrates was only about 31% TiO 2 . The combination of microwave radiation pre-treatment and the application of a column cell overcame both problems of poor flotability and the negative effect of slimes. When the Denver cell was replaced by a column cell and the massive ilmenite ore sample was pre-treated using microwave radiation for three minutes, the ilmenite concentrate grade increased from 31.1% TiO 2 to 42.9% TiO 2 and the titanium dioxide recovery increased from 68.5% to 90

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

    Science.gov (United States)

    Wang, Xinsheng; Hou, Junjian; Liu, Yanpei

    2018-06-01

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

  12. Source Term Model for Fine Particle Resuspension from Indoor Surfaces

    National Research Council Canada - National Science Library

    Kim, Yoojeong; Gidwani, Ashok; Sippola, Mark; Sohn, Chang W

    2008-01-01

    This Phase I effort developed a source term model for particle resuspension from indoor surfaces to be used as a source term boundary condition for CFD simulation of particle transport and dispersion in a building...

  13. Surface modification of titanium hydride with epoxy resin via microwave-assisted ball milling

    International Nuclear Information System (INIS)

    Ning, Rong; Chen, Ding; Zhang, Qianxia; Bian, Zhibing; Dai, Haixiong; Zhang, Chi

    2014-01-01

    Highlights: • TiH 2 was modified with epoxy resin by microwave-assisted ball milling. • The epoxy ring was opened under the coupling effect of microwave and ball milling. • Microwave-assisted ball milling improved the compatibility of TiH 2 with epoxy. - Abstract: Surface modification of titanium hydride with epoxy resin was carried out via microwave-assisted ball milling and the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR). A sedimentation test was performed to investigate the compatibility of the modified nano titanium hydride with the epoxy resin. The results show that the epoxy resin molecules were grafted on the surface of nano titanium hydride particles during the microwave-assisted ball milling process, which led to the improvement of compatibility between the nanoparticles and epoxy resin. According to the FT-IR, the grafting site was likely to be located around the epoxy group due to the fact that the epoxy ring was opened. However, compared with microwave-assisted ball milling, the conventional ball milling could not realize the surface modification, indicating that the coupling effect of mechanical force and microwave played a key role during the process

  14. Surface modification of upconverting nanoparticles by layer-by-layer assembled polyelectrolytes and metal ions.

    Science.gov (United States)

    Palo, Emilia; Salomäki, Mikko; Lastusaari, Mika

    2017-12-15

    Modificating and protecting the upconversion luminescence nanoparticles is important for their potential in various applications. In this work we demonstrate successful coating of the nanoparticles by a simple layer-by-layer method using negatively charged polyelectrolytes and neodymium ions. The layer fabrication conditions such as number of the bilayers, solution concentrations and selected polyelectrolytes were studied to find the most suitable conditions for the process. The bilayers were characterized and the presence of the desired components was studied and confirmed by various methods. In addition, the upconversion luminescence of the bilayered nanoparticles was studied to see the effect of the surface modification on the overall intensity. It was observed that with selected deposition concentrations the bilayer successfully shielded the particle resulting in stronger upconversion luminescence. The layer-by-layer method offers multiple possibilities to control the bilayer growth even further and thus gives promises that the use of upconverting nanoparticles in applications could become even easier with less modification steps in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

    Andrews, P; Fernandez Jalvo, Y

    1997-01-01

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

  18. Particle desorption mass spectrometric surface characterization

    International Nuclear Information System (INIS)

    Summers, W.R.

    1986-01-01

    The feasibility of utilizing 252 Cf-Particle Desorption Mass Spectrometry (PDMS) to characterize the surface region of solid samples has been evaluated. The PDMS experiment was adapted to an ultrahigh vacuum (UHV) environment and was configured so as to allow the analysis of thick as well as thin samples. This apparatus included an in situ sputter cleaning/depth profiling facility. The mass resolution was variable from 300 to 200 at 133 daltons by changing the drift length from 27 cm to 20 cm. Desorbed ions were focused by using either a dual grid assembly or an einzel lens. The overall instrumental transmission efficiency with the einzel lens operative was approximately 50%. The applicability of 252 Cf-PDMS to samples that were thick and insulating was demonstrated in the analysis of geological specimens. Pollucite, Microcline, Amblygonite, and Lepidolite were analyzed without complications associated with sample thickness or charge accumulation. Substitution occurring between the alkali metals in the environment was observed by PDMS and was corroborated by SIMS, XPS, and EMP analyses. The analysis of NBM SRM glasses addressed the suitability of combining the PDMS technique was sputter etching. This application demonstrated the ability of this technique to sense changes in the chemical environment brought about by sputter cleaning. The analysis of these samples also allowed the estimation of detection limits for lithium, rubidium, and cesium in a glass matrix as 300 ppm, 400 ppm, and 400 ppm, respectively. Sputter depth profiling combined with 252 Cf-PDMS analysis of an aluminum layer on a silicon substrate established the utility of the PDMS technique in surface characterization

  19. Enhancement in electrical conductivity of pastes containing submicron Ag-coated Cu filler with palmitic acid surface modification

    Science.gov (United States)

    Choi, Eun Byeol; Lee, Jong-Hyun

    2017-09-01

    The fabrication and applied use of submicron Ag-coated Cu (Cu@Ag) particles as a filler material for epoxy-based conductive pastes having the advantages of a lower material cost and antioxidation behavior were studied. Submicron Cu@Ag particles were successfully prepared and surface-modified using palmitic acid. Diffuse reflectance infrared Fourier transform spectroscopy and thermogravimetric differential scanning calorimetry results indicated the formation of an organic layer by the chemical interaction between the Cu@Ag surface and palmitic acid and the survival of the organic layer after treatment at 160 °C for 3 h in air. The printed pastes containing both commercial micron Cu@Ag flakes and the fabricated submicron Cu@Ag particles showed a greatly reduced electrical resistivity (4.68 × 10-4 Ω cm) after surface modification compared to an initial value of 1.85 × 10-3 Ω cm when cured.

  20. Surface modification of calcium hydroxyapatite by grafting of etidronic acid

    Science.gov (United States)

    Othmani, Masseoud; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi

    2013-06-01

    The surface of prepared calcium hydroxyapatite CaHAp has been modified by grafting the etidronic acid (ETD). For that purpose, CaHAp powders have been suspended in an aqueous etidronate solution with different concentrations. The obtained composites CaHAp-(ETD) were characterized by TEM and AFM techniques to determinate morphological properties and were also characterized by XRD, IR, NMR and chemical and thermal analysis to determinate their physico-chemical properties and essentially the nature of the interaction between the inorganic support and the grafted organic ETD. After reaction with ETD, XRD powder analysis shows that the apatitic structure remains unchanged with slight affectation of its crystallinity. The presence of etidronate fragment bounded to hydroxyapatite was confirmed by IR and solid-state NMR spectroscopy. TEM and AFM techniques indicate that the presence of etidronate changes the morphology of the particles. Basing on the obtained results, a reactional mechanism was proposed to explain the formation of covalent Casbnd Osbnd Porg bonds on the hydroxyapatite surface between the superficial hydroxyl groups (tbnd Casbnd OH) of the apatite and phosphonate group (Psbnd OH) of etidronate.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-29

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

  2. Surface-Modification of Carbonate Apatite Nanoparticles Enhances Delivery and Cytotoxicity of Gemcitabine and Anastrozole in Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Fitya Syarifa Mozar

    2017-06-01

    Full Text Available pH sensitive nanoparticles of carbonate apatite (CA have been proven to be effective delivery vehicles for DNA, siRNAs and proteins. More recently, conventional anti-cancer drugs, such as doxorubicin, methotrexate and cyclophosphamide have been successfully incorporated into CA for intracellular delivery to breast cancer cells. However, physical and chemical properties of drug molecules appeared to affect their interactions with CA, with hydrophillic drug so far exhibiting better binding affinity and cellular uptakes compared to hydrophobic drugs. In this study, anastrozole, a non-steroidal aromatase inhibitor which is largely hydrophobic, and gemcitabine, a hydrophilic nucleoside inhibitor were used as solubility models of chemotherapy drug. Aggregation tendency of poorly soluble drugs resulting in larger particle-drug complex size might be the main factor hindering their delivery effectiveness. For the first time, surface modification of CA with poly(ethylene glycol (PEG has shown promising result to drastically reduce anastrozole- loaded CA particle size, from approximately 1000 to 500 nm based on zeta sizer analysis. Besides PEG, a cell specific ligand, in this case fibronectin, was attached to the particles in order to facilitate receptor mediated endocytosis based on fibronectin–integrin interaction. High-performance liquid chromatography (HPLC was performed to measure uptake of the drugs by breast cancer cells, revealing that surface modification increased the drug uptake, especially for the hydrophobic drug, compared to the uncoated particles and the free drug. In vitro chemosensitivity assay and in vivo tumor regression study also showed that coated apatite/drug nanoparticle complexes presented higher cytotoxicity and tumor regression effects than uncoated apatite/drug nanoparticles and free drugs, indicating that surface modification successfully created optimum particles size with the consequence of more effective uptake along with

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

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

    Science.gov (United States)

    Krishnamoorthy, Jayaraman

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

  5. Surface modification and antimicrobial properties of cellulose nanocrystals

    Science.gov (United States)

    Bespalova, Yulia A.

    Surface modification of cellulose nanocrystals (CNC) was performed by acetylation and subsequent reaction with various tertiary amines with different lengths of alkyl groups. Chloroacetic anhydride (95%) was used for acetylation. The acetylation of CNC was confirmed using IR spectroscopy. The bands associated with C=0 stretching (1740 cm-1) and C-Cl stretching (793 cm -1) was present in the acetylated CNC but they were absent in the neat CNC. It has been suggested that the primary hydroxyl groups of CNC are substituted by chloro acetyl groups during acetylation reaction. Subsequent reaction of chloro acetylated CNC with N, N - Dimethyl ethylamine, N, N - Dimethyl hexylamine, N, N - Dimethyl dodecylamine, N, N - Dimethyl hexadecylamine and N, N - Dimethyl decylamine formed quaternary ammonium salts. These quaternary ammonium salts were characterized by FTIR and solid state13C NMR spectroscopy. FTIR spectra of five types of quaternary ammonium salts of CNC are similar and they showed infrared bands at 2905 -1 and 2850 cm-1, attributed to symmetrical and unsymmetrical C-H stretching vibration. The absence of C-Cl band at 793 cm-1 proves that quaternary salt formation was successful. The 13C NMR spectrum of quaternary ammonium modified CNC with N, N - Dimethyl dodecylamine shows several additional resonances ranging from 14.5 ppm to 58.0 ppm when compared to 13C NMR spectrum of pure CNC. This evidence proves that long alkyl chains have been added to the pure CNC. The disc diffusion method confirmed that quaternary ammonium modified CNCs with a chain longer than ten carbons are effective antimicrobial agents against Staphylococcus aureus and E. coli bacteria. Pure CNC and quaternary ammonium modified CNCs with an alkyl chain length of ten or less were not able to inhibit bacteria growth.

  6. Large Eddy Simulation of Turbulence Modification and Particle Dispersion in a Fully-Developed Pipe Flow

    Science.gov (United States)

    Rani, Sarma; Pratap Vanka, Surya

    1999-11-01

    A LES study of the modification of turbulence in a fully-developed turbulent pipe flow by dispersed heavy particles at Re_τ = 360 is presented. A 64 (radial) x 64 (azimuthal) x 128 (axial) grid has been used. An Eulerian-Lagrangian approach has been used for treating the continuous and the dispersed phases respectively. The particle equation of motion included only the drag force. Three different LES models are used in the continuous fluid simulation: (i) A “No-Model” LES (coarse-grid DNS) (ii) Smagorinsky’s model and (iii) Schumann’s model . The motivation behind employing the Schumann’s model is to study the impact of sub-grid-scale fluctuations on the particle motion and their (SGS fluctuations) modulation, in turn, by the particles. The effect of particles on fluid turbulence is investigated by tracking 100000 particles of different diameters. Our studies confirm the preferential concentration of particles in the near wall region. It is observed that the inclusion of two-way coupling reduces the preferential concentration of particles. In addition, it was found that two-way coupling attenuates the fluid turbulence. However, we expect the above trends to differ depending upon the particle diameter, volumetric and mass fractions. The effect of SGS fluctuations on the particle dispersion and turbulence modulation is also being investigated. Other relevant statistics for the continuous and the dispersed phases are collected for the cases of one-way and two-way coupling. These statistics are compared to study the modulation of turbulence by the particles.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-30

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2009-12-09

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

  10. Dry deposition of particles to ocean surfaces

    NARCIS (Netherlands)

    Larsen, S.E.; Edson, J.B.; Hummelshoj, P.; Jensen, N.O.; Leeuw, G. de; Mestayer, P.G.

    1995-01-01

    Dry deposition of atmospheric particles mainly depends on wind speed and particle diameter. The dry deposition velocity, Vd, is found to vary by a factor of 100-1,000 with diameter in a likely diameter range, adding uncertainty to deposition estimates, because the diameter distribution for many

  11. Metastable states of plasma particles close to a charged surface

    Energy Technology Data Exchange (ETDEWEB)

    Shavlov, A. V., E-mail: shavlov@ikz.ru [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation); Tyumen State Oil and Gas University, 38, Volodarskogo St., 625000, Tyumen (Russian Federation); Dzhumandzhi, V. A. [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation)

    2015-09-15

    The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge, there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed. These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles.

  12. Characterization of triboelectrically charged particles deposited on dielectric surfaces

    Science.gov (United States)

    Nesterov, A.; Löffler, F.; Cheng, Yun-Chien; Torralba, G.; König, K.; Hausmann, M.; Lindenstruth, V.; Stadler, V.; Bischoff, F. R.; Breitling, F.

    2010-04-01

    A device for the measurement of q/m-values and charge degradation of triboelectrically charged particles deposited on a surface was developed. The setup is based on the integration of currents, which are induced in a Faraday cage by insertion of a solid support covered with charged particles. The conductivity of different particle supports was taken into account. The 'blow-off' method, in which the particles are first deposited, and then blown off using an air stream, can be used for characterization of triboelectric properties of particles relative to different surfaces.

  13. Characterization of triboelectrically charged particles deposited on dielectric surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Nesterov, A; Torralba, G; Hausmann, M; Lindenstruth, V [Kirchhoff Institute of Physics, In Neuenheimer Feld 227, Heidelberg (Germany); Loeffler, F; Cheng, Yun-Chien; Koenig, K; Stadler, V; Bischoff, F R [German Cancer Research Centre, In Neuenheimer Feld 280, Heidelberg (Germany); Breitling, F, E-mail: Frank.Breitling@KIT.ed, E-mail: alexander.nesterov-mueller@kit.ed [Karlsruhe Institute of Technology (KIT), Institute for Microstructure Technology, Herrmann von Helmholtzplatz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2010-04-28

    A device for the measurement of q/m-values and charge degradation of triboelectrically charged particles deposited on a surface was developed. The setup is based on the integration of currents, which are induced in a Faraday cage by insertion of a solid support covered with charged particles. The conductivity of different particle supports was taken into account. The 'blow-off' method, in which the particles are first deposited, and then blown off using an air stream, can be used for characterization of triboelectric properties of particles relative to different surfaces.

  14. Dispersion and deagglomerat1on of nano-SiO2 particles with a silane modification reagent in supercritical CO2

    Directory of Open Access Journals (Sweden)

    Stojanović Dušica B.

    2007-01-01

    Full Text Available The supercritical CO2 method was used in order to perform deagglomeration and improve the dispersion of nano-SiO2 particles. γ-Met-hacryloxypropyltrimethoxysilane was used as the surface modification reagent. The conventional method for coating nano-SiO2 particles was used as the comparison method. Considerable improvement of the dispersion and deagglomeration was found using supercritical CO2. Analysis of the TEM micrographs and DLS results showed the reduction of the average size of the agglomerates with the silane coupling reagent. Thermogravimetric analysis (TGA showed that the particles treated in super­critical CO2 were more thermally stable than particles treated by conventional method. Encapsulation of several particles coated with the silane coupling reagent was observed in certain parts of the primary particles. A chemical reaction takes place between the modification reagent, MEMO silane, and active hydroxyl groups on the surface of the nano-SiO2 particles. A larger quantity of MEMO silane reacted using the con­ventional method instead of the supercritical method. On the other hand, the reacted silane molecules were better arranged around the particle surface in the supercritical method because of the formation of covalent or self-assembled structures. Polycondensed structures were preferentially obtained in the conventional method. This was achieved by using supercritical CO2, which has a high solvating power such as organic solvents and physical properties (low viscosity, low surface tension and high diffusion coefficient similar to gases on the other side. These properties enable the sufficient and uniform wettability of nano-SiO2 particle surfaces. These results are important for obtaining nanofillers with improved dispersion and polymer wettability. Such nanofillers can be used to obtain composite materials with considerably improved mechanical characteristics.

  15. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture...... but may provide significant surface area. Hence, the study substantiates that particles in RAS provide surface area supporting bacterial activity, and that particles play a key role in controlling the bacterial carrying capacity at least in less intensive RAS. Applying fast, culture-independent techniques......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  16. Plasma Surface Modification of Polyaramid Fibers for Protective Clothing

    Science.gov (United States)

    Widodo, Mohamad

    2011-12-01

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

  17. Effect of surface modifications on the bond strength of zirconia ceramic with resin cement resin.

    Science.gov (United States)

    Hallmann, Lubica; Ulmer, Peter; Lehmann, Frank; Wille, Sebastian; Polonskyi, Oleksander; Johannes, Martina; Köbel, Stefan; Trottenberg, Thomas; Bornholdt, Sven; Haase, Fabian; Kersten, Holger; Kern, Matthias

    2016-05-01

    Purpose of this in vitro study was to evaluate the effect of surface modifications on the tensile bond strength between zirconia ceramic and resin. Zirconia ceramic surfaces were treated with 150-μm abrasive alumina particles, 150-μm abrasive zirconia particles, argon-ion bombardment, gas plasma, and piranha solution (H2SO4:H2O2=3:1). In addition, slip casting surfaces were examined. Untreated surfaces were used as the control group. Tensile bond strengths (TBS) were measured after water storage for 3 days or 150 days with additional 37,500 thermal cycling for artificial aging. Statistical analyses were performed with 1-way and 3-way ANOVA, followed by comparison of means with the Tukey HSD test. After storage in distilled water for three days at 37 °C, the highest mean tensile bond strengths (TBS) were observed for zirconia ceramic surfaces abraded with 150-μm abrasive alumina particles (TBS(AAP)=37.3 MPa, TBS(CAAP)=40.4 MPa), and 150-μm abrasive zirconia particles (TBS(AZP)=34.8 MPa, TBS(CAZP)=35.8 MPa). Also a high TBS was observed for specimens treated with argon-ion bombardment (TBS(BAI)=37.8 MPa). After 150 days of storage, specimens abraded with 150-μm abrasive alumina particles and 150-μm abrasive zirconia particles revealed high TBS (TBS(AAP)=37.6 MPa, TBS(CAAP)=33.0 MPa, TBS(AZP)=22.1 MPa and TBS(CAZP)=22.8 MPa). A high TBS was observed also for specimens prepared with slip casting (TBS(SC)=30.0 MPa). A decrease of TBS was observed for control specimens (TBS(UNT)=12.5 MPa, TBS(CUNT)=9.0 MPa), specimens treated with argon-ion bombardment (TBS(BAI)=10.3 MPa) and gas plasma (TBS(GP)=11.0 MPa). A decrease of TBS was observed also for specimens treated with piranha solution (TBS(PS)=3.9 MPa, TBS(CPS)=4.1 MPa). A significant difference in TBS after three days storage was observed for specimens treated with different methods (p0.05), CAAP(p>0.05) and SC(p>0.05). However, the failure patterns of debonded specimens prepared with 150-μm abrasive zirconia

  18. Particle separation by external fields on periodic surfaces

    International Nuclear Information System (INIS)

    Sancho, J M; Khoury, M; Lindenberg, K; Lacasta, A M

    2005-01-01

    Particles moving on perfect periodic surfaces under the influence of external forces may move along directions that deviate from that of the force. We briefly recall previous results for transport of particles on surfaces with periodic traps or periodic obstacles driven by a constant external force, and present new results for particles moving in a harmonic periodic potential. The sorting properties are explored as a function of a number of control parameters, specifically the friction, force amplitude and direction, temperature, and lattice constants

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

    Energy Technology Data Exchange (ETDEWEB)

    Stanishevsky, Andrei V., E-mail: astan@uab.edu; Walock, Michael J.; Catledge, Shane A.

    2015-12-01

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

  20. Cloaking of 2D particle geometries in a surface medium

    Energy Technology Data Exchange (ETDEWEB)

    Alexopoulos, A., E-mail: Aris.Alexopoulos@dsto.defence.gov.au [Electronic Warfare and Radar Division, Defence Science and Technology Organisation (DSTO), PO Box 1500, Edinburgh 5111 (Australia); Yau, K.S.B. [Electronic Warfare and Radar Division, Defence Science and Technology Organisation (DSTO), PO Box 1500, Edinburgh 5111 (Australia)

    2013-06-17

    We theoretically examine the cloaking condition for two-dimensional particles with varying geometry embedded inside a surface medium. General solutions are obtained for multi-layer particle configurations with either all positive or partially negative constitutive parameters respectively. Cloaking of particle geometries that are large relative to the incident wavelength is demonstrated. Theoretical predictions are compared to full-wave numerical simulations for arrays of particles consisting of different geometries.

  1. Modifications of the optical properties for DAM-ADC nuclear track detector exposed to alpha particles

    Science.gov (United States)

    Rammah, Y. S.; Awad, E. M.

    2018-05-01

    Modifications of the optical properties of diallyl maleate-allyl diglycol carbonate (DAM-ADC) nuclear detector induced by alpha particles are described. DAM-ADC samples were irradiated perpendicularly by thin 241Am disk source that emits alpha particles with 5.48 MeV. The optical absorption has been measured using the ultraviolet-visible (UV-1100) spectroscopy. It was found that DAM-ADC polymer shows substantial modifications in its optical characteristics upon irradiated with alpha particles with different energies. The optical energy band gap (Egap) for the detector was calculated for the direct and the indirect allowed transitions in K-space using two approaches (Tauc's model and absorption spectrum fitting (ASF) method). Urbach's energy (Ea), number of carbon atoms per conjugated length (N), number of carbon atoms per cluster (M), and refractive index (n) for the present samples were determined. Results reveal that the values of energy gap in direct transition are greater than those of indirect, before and after irradiation. (Egap), (Ea), (N), (M), and (n) of the present samples are changed significantly with irradiation time and value of alpha energy. Results reflect the possibility of using DAM-ADC polymer track detectors to estimate alpha particle energies using the variation of the absorbance.

  2. [Construction of Lactobacillus rhamnosus GG particles surface display system].

    Science.gov (United States)

    Su, Runyu; Nie, Boyao; Yuan, Shengling; Tao, Haoxia; Liu, Chunjie; Yang, Bailiang; Wang, Yanchun

    2017-01-25

    To describe a novel particles surface display system which is consisted of gram-positive enhancer matrix (GEM) particles and anchor proteins for bacteria-like particles vaccines, we treated Lactobacillus rhamnosus GG bacteria with 10% heated-TCA for preparing GEM particles, and then identified the harvested GEM particles by electron microscopy, RT-PCR and SDS-PAGE. Meanwhile, Escherichia coli was induced to express hybrid proteins PA3-EGFP and P60-EGFP, and GEM particles were incubated with them. Then binding of anchor proteins were determined by Western blotting, transmission electron microscopy, fluorescence microscopy and spectrofluorometry. GEM particles preserved original size and shape, and proteins and DNA contents of GEM particles were released substantially. The two anchor proteins both had efficiently immobilized on the surface of GEM. GEM particles that were bounded by anchor proteins were brushy. The fluorescence of GEM particles anchoring PA3 was slightly brighter than P60, but the difference was not significant (P>0.05). GEM particles prepared from L. rhamnosus GG have a good binding efficiency with anchor proteins PA3-EGFP and P60-EGFP. Therefore, this novel foreign protein surface display system could be used for bacteria-like particle vaccines.

  3. Stable perovskite solar cells by surface modification with surfactant molecules

    Energy Technology Data Exchange (ETDEWEB)

    Holanda, Matheus Serra de; Nogueira, Ana Flavia, E-mail: mholandabsb@outlook.com [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica

    2016-07-01

    Full text: Surface modification on organic-inorganic perovskite films using dodecylammonium chloride was done to improve the stability of the material over the air moisture, which is considered extremely harmful to these materials and complicates their application on solar cell technology. Perovskite CH{sub 3}NH{sub 3}PbI{sub 3} was prepared by single step method using a solution containing PbI{sub 2} and CH{sub 3}NH{sub 3}I on DMF:DMSO (2:1) on a concentration of 0.88 mol L{sup -1}. The film was deposited over a planar film of TiO{sub 2}, previously deposited over FTO glass, by using spin-casting method. 25 μL of the solution was spread over the substrate which was turned at 4000 RPM for 45 s. In the last 10 s, 800 μL of monochlorobenzene was dropped. The film was submitted to a thermal treatment so the conversion of the perovskite could be completed. After the thermal treatment, the modifier was spin coated over the perovskite film from 5 and 10 mg mL{sup -1} solutions of the dodecylammonium chloride in chloroform. The perovskite films were characterized by SEM, XRD and UV-Vis spectroscopy. SEM images have shown that the modifiers agglomerate and they cover the perovskite film, forming a protection layer. XRD and UV-Vis carried out after the film preparation, 7 and 15 days after the deposition. The first results show that the protection layer is able to avoid degradation of the perovskite film. Photovoltaic devices were prepared by depositing Spiro-OMeTAD as HTM layer and gold as electrode. It was observed that the increase on the thickness of the surfactant layer causes a decrease on the short-circuit current density (JSC), which is expected since is starts to act like an insulating layer. This effect is also the cause of the reduction of the fill factor (FF). More experiments need to be carried out to improve the solar cells devices, but the present data has shown the potential of the method developed, which uses easy access surfactants and a simple

  4. Stable perovskite solar cells by surface modification with surfactant molecules

    International Nuclear Information System (INIS)

    Holanda, Matheus Serra de; Nogueira, Ana Flavia

    2016-01-01

    Full text: Surface modification on organic-inorganic perovskite films using dodecylammonium chloride was done to improve the stability of the material over the air moisture, which is considered extremely harmful to these materials and complicates their application on solar cell technology. Perovskite CH 3 NH 3 PbI 3 was prepared by single step method using a solution containing PbI 2 and CH 3 NH 3 I on DMF:DMSO (2:1) on a concentration of 0.88 mol L -1 . The film was deposited over a planar film of TiO 2 , previously deposited over FTO glass, by using spin-casting method. 25 μL of the solution was spread over the substrate which was turned at 4000 RPM for 45 s. In the last 10 s, 800 μL of monochlorobenzene was dropped. The film was submitted to a thermal treatment so the conversion of the perovskite could be completed. After the thermal treatment, the modifier was spin coated over the perovskite film from 5 and 10 mg mL -1 solutions of the dodecylammonium chloride in chloroform. The perovskite films were characterized by SEM, XRD and UV-Vis spectroscopy. SEM images have shown that the modifiers agglomerate and they cover the perovskite film, forming a protection layer. XRD and UV-Vis carried out after the film preparation, 7 and 15 days after the deposition. The first results show that the protection layer is able to avoid degradation of the perovskite film. Photovoltaic devices were prepared by depositing Spiro-OMeTAD as HTM layer and gold as electrode. It was observed that the increase on the thickness of the surfactant layer causes a decrease on the short-circuit current density (JSC), which is expected since is starts to act like an insulating layer. This effect is also the cause of the reduction of the fill factor (FF). More experiments need to be carried out to improve the solar cells devices, but the present data has shown the potential of the method developed, which uses easy access surfactants and a simple preparation method to improve the stability of

  5. Surface Navigation Using Optimized Waypoints and Particle Swarm Optimization

    Science.gov (United States)

    Birge, Brian

    2013-01-01

    The design priority for manned space exploration missions is almost always placed on human safety. Proposed manned surface exploration tasks (lunar, asteroid sample returns, Mars) have the possibility of astronauts traveling several kilometers away from a home base. Deviations from preplanned paths are expected while exploring. In a time-critical emergency situation, there is a need to develop an optimal home base return path. The return path may or may not be similar to the outbound path, and what defines optimal may change with, and even within, each mission. A novel path planning algorithm and prototype program was developed using biologically inspired particle swarm optimization (PSO) that generates an optimal path of traversal while avoiding obstacles. Applications include emergency path planning on lunar, Martian, and/or asteroid surfaces, generating multiple scenarios for outbound missions, Earth-based search and rescue, as well as human manual traversal and/or path integration into robotic control systems. The strategy allows for a changing environment, and can be re-tasked at will and run in real-time situations. Given a random extraterrestrial planetary or small body surface position, the goal was to find the fastest (or shortest) path to an arbitrary position such as a safe zone or geographic objective, subject to possibly varying constraints. The problem requires a workable solution 100% of the time, though it does not require the absolute theoretical optimum. Obstacles should be avoided, but if they cannot be, then the algorithm needs to be smart enough to recognize this and deal with it. With some modifications, it works with non-stationary error topologies as well.

  6. Layer-by-layer modification of high surface curvature nanoparticles with weak polyelectrolytes using a multiphase solvent precipitation process.

    Science.gov (United States)

    Nagaraja, Ashvin T; You, Yil-Hwan; Choi, Jeong-Wan; Hwang, Jin-Ha; Meissner, Kenith E; McShane, Michael J

    2016-03-15

    The layer-by-layer modification of ≈5 nm mercaptocarboxylic acid stabilized gold nanoparticles was studied in an effort to illustrate effective means to overcome practical issues in handling and performing surface modification of such extremely small materials. To accomplish this, each layer deposition cycle was separated into a multi-step process wherein solution pH was controlled in two distinct phases of polyelectrolyte adsorption and centrifugation. Additionally, a solvent precipitation step was introduced to make processing more amenable by concentrating the sample and exchanging solution pH before ultracentrifugation. The pH-dependent assembly on gold nanoparticles was assessed after each layer deposition cycle by monitoring the plasmon peak absorbance location, surface charge, and the percentage of nanoparticles recovered. The selection of solution pH during the adsorption phase was found to be a critical parameter to enhance particle recovery and maximize surface charge when coating with weak polyelectrolytes. One bilayer was deposited with a high yield and the modified particles exhibited enhanced colloidal stability across a broad pH range and increased ionic strength. These findings support the adoption of this multi-step processing approach as an effective and generalizable approach to improve stability of high surface curvature particles. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Deposition of fine and ultrafine particles on indoor surface materials

    DEFF Research Database (Denmark)

    Afshari, Alireza; Reinhold, Claus

    2008-01-01

    -scale test chamber. Experiments took place in a 32 m3 chamber with walls and ceiling made of glass. Prior to each experiment the chamber was flushed with outdoor air to reach an initial particle concentration typical of indoor air in buildings with natural ventilation. The decay of particle concentrations...... The aim of this study was the experimental determination of particle deposition for both different particle size fractions and different indoor surface materials. The selected surface materials were glass, gypsum board, carpet, and curtain. These materials were tested vertically in a full...... was monitored. Seven particle size fractions were studied. These comprised ultrafine and fine particles. Deposition was higher on carpet and curtain than on glass and gypsum board. Particles ranging from 0.3 to 0.5 µm had the lowest deposition. This fraction also has the highest penetration and its indoor...

  8. Surface modification of hydroxyapatite with poly(methyl methacrylate) via surface-initiated ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yan; Zhang Xi; Yan Jinliang; Xiao Yan [Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Lang Meidong, E-mail: mdlang@ecust.edu.cn [Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2011-05-01

    This article describes the fabrication of hydroxyapatite (HAP) nanocomposites grafted with poly(methyl methacrylate) (PMMA). Surface-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was carried out from hydroxyapatite particles derivatized with ATRP initiators. The structure and properties of the nanocomposites were investigated by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), differential scanning calorimeter (DSC) measurements, and contact angle analyses. TGA was used to estimate the grafting density of ATRP initiators (0.49 initiator/nm{sup 2}) and the amount of grafted PMMA on the HAP surface. The contact angle analyses indicated that grafting PMMA onto the HAP surface dramatically increased the hydrophobicity of the surface. Moreover, the HAP nanocomposites showed excellent dispersibility in both aqueous solution and organic solvent.

  9. Surface modification of hydroxyapatite with poly(methyl methacrylate) via surface-initiated ATRP

    International Nuclear Information System (INIS)

    Wang Yan; Zhang Xi; Yan Jinliang; Xiao Yan; Lang Meidong

    2011-01-01

    This article describes the fabrication of hydroxyapatite (HAP) nanocomposites grafted with poly(methyl methacrylate) (PMMA). Surface-initiated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was carried out from hydroxyapatite particles derivatized with ATRP initiators. The structure and properties of the nanocomposites were investigated by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), differential scanning calorimeter (DSC) measurements, and contact angle analyses. TGA was used to estimate the grafting density of ATRP initiators (0.49 initiator/nm 2 ) and the amount of grafted PMMA on the HAP surface. The contact angle analyses indicated that grafting PMMA onto the HAP surface dramatically increased the hydrophobicity of the surface. Moreover, the HAP nanocomposites showed excellent dispersibility in both aqueous solution and organic solvent.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-30

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  12. Switching of localized surface plasmon resonance of gold nanoparticles on a GeSbTe film mediated by nanoscale phase change and modification of surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Hira, T.; Homma, T.; Uchiyama, T.; Kuwamura, K.; Saiki, T. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522 (Japan)

    2013-12-09

    As a platform for active nanophotonics, localized surface plasmon resonance (LSPR) switching via interaction with a chalcogenide phase change material (GeSbTe) was investigated. We performed single-particle spectroscopy of gold nanoparticles placed on a GeSbTe thin film. By irradiation with a femtosecond pulsed laser for amorphization and a continuous wave laser for crystallization, significant switching behavior of the LSPR band due to the interaction of GeSbTe was observed. The switching mechanism was explained in terms of both a change in the refractive index and a modification of surface morphology accompanying volume expansion and reduction of GeSbTe.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  14. Microwave assisted organic modification and surface functionalization of Phyllosilicates

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-11-01

    Full Text Available decoration of raw montmorillonite clays with metal (Ag, Fe) nano-particles. The composites were characterized by transmission electron microscopy; x-ray diffraction; energy dispersive x-ray spectroscopy and Fourier transform infrared spectroscopy. Compared...

  15. Plasma-surface interactions under high heat and particle fluxes

    NARCIS (Netherlands)

    De Temmerman, G.; Bystrov, K.; Liu, F.; Liu, W.; Morgan, T.; Tanyeli, I.; van den Berg, M.; Xu, H.; Zielinski, J.

    2013-01-01

    The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface

  16. Diffusion of particles adsorbed on reconstructive surface

    Czech Academy of Sciences Publication Activity Database

    Tarasenko A., Nataliya; Tarasenko, Alexander; Jastrabík, Lubomír

    2005-01-01

    Roč. 11, č. 1 (2005), s. 485-489 ISSN 0929-5607 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z10100522 Keywords : lattice gas * surface reconstruction * surface diffusion * phase transitions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.323, year: 2005

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

    Science.gov (United States)

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

    2014-07-09

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

  18. Surface Modification of Exfoliated Graphite Nano-Reinforcements, Phase II

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2017-03-01

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

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

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  1. Surface modification of polymer nanofibres by plasma treatment

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  2. 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)

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

    Science.gov (United States)

    Lee, TaeGi; Shimura, Kunio; Kim, DaeGwi

    2018-05-03

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

  4. Architecting boron nanostructure on the diamond particle surface

    International Nuclear Information System (INIS)

    Bai, H.; Dai, D.; Yu, J.H.; Nishimura, K.; Sasaoka, S.; Jiang, N.

    2014-01-01

    The present study provides an efficient approach for nano-functionalization of diamond powders. Boron nanostructure can be grown on diamond particle entire surface by a simple heat-treatment process. After treatment, various boron nanoforms were grown on the diamond particle surface at different processing temperature. High-density boron nanowires (BNWs) grow on the diamond particle entire surface at 1333 K, while nanopillars cover diamond powders when the heat treatment process is performed at 1393 K. The influence of the pretreatment temperature on the microstructure and thermal conductivity of Cu/diamond composites were investigated. Cu/diamond composites with high thermal conductivity of 670 W (m K) −1 was obtained, which was achieved by the formation of large number of nanowires and nanopillars on the diamond particle surface.

  5. Surface modification of 5083 Al alloy by electrical discharge alloying processing with a 75 mass% Si-Fe alloy electrode

    Energy Technology Data Exchange (ETDEWEB)

    Stambekova, Kuralay [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China); Lin, Hung-Mao [Department of Mechanical Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan (China); Uan, Jun-Yen, E-mail: jyuan@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China)

    2012-03-01

    This study experimentally investigates the surface modification of 5083 Al alloy by the electrical discharge alloying (EDA) process with a Si-Fe alloy as an electrode. Samples were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), micro-hardness and corrosion resistance tests. The micro-hardness of EDA alloyed layer was evidently higher than that of the base metal (5083 Al alloy). The TEM results show that the matrix of the alloyed layer has an amorphous-like structure; the matrix contains fine needle-like Si particles, block-like Si particles and nano-size Al{sub 4.5}FeSi and Al{sub 13}Fe{sub 4} particles. The TEM results support experimental results for the high hardness of the alloyed layer. Moreover, the EDA alloyed layer with composite microstructures has good corrosion resistance in NaCl aqueous solution.

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

    African Journals Online (AJOL)

    MICHAEL

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

  7. Surface modification method for reactor incore structural component

    International Nuclear Information System (INIS)

    Obata, Minoru; Sudo, Akira.

    1996-01-01

    A large number of metal or ceramic small spheres accelerated by pressurized air are collided against a surface of a reactor incore structures or a welded surface of the structural components, and then finishing is applied by polishing to form compression stresses on the surface. This can change residual stresses into compressive stress without increasing the strength of the surface. Accordingly, stress corrosion crackings of the incore structural components or welded portions thereof can be prevented thereby enabling to extend the working life of equipments. (T.M.)

  8. Modification of BSCCO surface by excimer laser annealing

    International Nuclear Information System (INIS)

    Ibi, A.; Akitsu, T.; Matsuzawa, H.

    2002-01-01

    Irradiation of Kr-F excimer laser onto the BSCCO calcined pellets changed their surface to be amorphous. SEM micrographs showed that sintering of the irradiated pellets recrystallized the surface layer and much reduced the intergrain gaps as compared with only sintered pellets, whereas the internal structure of the irradiated pellets remained unchanged. This processing made the surface-layer grains be tightly connected, resulting in the higher critical temperature than the conventionally sintered samples. We can say that excimer laser annealing process is a novel scheme to reduce the surface weak-link of the high Tc superconductors. (author)

  9. A Comparison of Selected Modifications of the Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Michala Jakubcová

    2014-01-01

    Full Text Available We compare 27 modifications of the original particle swarm optimization (PSO algorithm. The analysis evaluated nine basic PSO types, which differ according to the swarm evolution as controlled by various inertia weights and constriction factor. Each of the basic PSO modifications was analyzed using three different distributed strategies. In the first strategy, the entire swarm population is considered as one unit (OC-PSO, the second strategy periodically partitions the population into equally large complexes according to the particle’s functional value (SCE-PSO, and the final strategy periodically splits the swarm population into complexes using random permutation (SCERand-PSO. All variants are tested using 11 benchmark functions that were prepared for the special session on real-parameter optimization of CEC 2005. It was found that the best modification of the PSO algorithm is a variant with adaptive inertia weight. The best distribution strategy is SCE-PSO, which gives better results than do OC-PSO and SCERand-PSO for seven functions. The sphere function showed no significant difference between SCE-PSO and SCERand-PSO. It follows that a shuffling mechanism improves the optimization process.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  11. Surface modification of lignocellulosic fibers using high-frequency ultrasound

    Science.gov (United States)

    Jayant B. Gadhe; Ram B. Gupta; Thomas Elder

    2005-01-01

    Enzymatic and chemical oxidation of fiber surfaces has been reported in the literature as a method for producing medium density fiberboards without using synthetic adhesives. This work focuses on modifying the surface properties of wood fibers by the generation of free radicals using high-frequency ultrasound. A sonochemical reactor operating at 610 kHz is used to...

  12. Effect of nanodiamond modification of siloxane surfaces on stem cell behaviour

    International Nuclear Information System (INIS)

    Keremidarska, M; Krasteva, N; Hikov, T; Radeva, E; Pramatarova, L

    2014-01-01

    Mesenchymal stem cells (MSCs) hold a great promise for use in many cell therapies and tissue engineering due to their remarkable potential to replicate indefinitely and differentiate into various cell types. Many efforts have been put to study the factors controlling stem cell differentiation. However, still little knowledge has been gained to what extent biomaterials properties influence stem cell adhesion, growth and differentiation. Research utilizing bone marrow-derived MSCs has concentrated on development of specific materials which can enhance specific differentiation of stem cells e.g. osteogenic and chondrogenic. In the present work we have modified an organosilane, hexamethyldisiloxane (HMDS) with detonation nanodiamond (DND) particles aiming to improve adhesion, growth and osteodifferentiation of rat mesenchymal stem cells. HMDS/DND films were deposited on cover glass using two approaches: premixing of both compounds, followed by plasma polymerization (PP) and PP of HMDS followed by plasma deposition of DND particles. We did not observe however an increase in rMSCs adhesion and growth on DND-modified PPHMDS surfaces compared to unmodified PPHMDS. When we studied alkaline phosphatase (ALP) activity, which is a major sign for early osteodifferentiation, we found the highest ALP activity on the PPHMDS/DND material, prepared by consequent deposition while on the other composite material ALP activity was the lowest. These results suggested that DND-modified materials were able to control osteodifferention in MSCs depending on the deposition approach. Modification of HMDS with DND particles by consequent plasma deposition seems to be a promising approach to produce biomaterials capable to guide stem cell differentiation toward osteoblasts and thus to be used in bone tissue engineering

  13. Effect of nanodiamond modification of siloxane surfaces on stem cell behaviour

    Science.gov (United States)

    Keremidarska, M.; Hikov, T.; Radeva, E.; Pramatarova, L.; Krasteva, N.

    2014-12-01

    Mesenchymal stem cells (MSCs) hold a great promise for use in many cell therapies and tissue engineering due to their remarkable potential to replicate indefinitely and differentiate into various cell types. Many efforts have been put to study the factors controlling stem cell differentiation. However, still little knowledge has been gained to what extent biomaterials properties influence stem cell adhesion, growth and differentiation. Research utilizing bone marrow-derived MSCs has concentrated on development of specific materials which can enhance specific differentiation of stem cells e.g. osteogenic and chondrogenic. In the present work we have modified an organosilane, hexamethyldisiloxane (HMDS) with detonation nanodiamond (DND) particles aiming to improve adhesion, growth and osteodifferentiation of rat mesenchymal stem cells. HMDS/DND films were deposited on cover glass using two approaches: premixing of both compounds, followed by plasma polymerization (PP) and PP of HMDS followed by plasma deposition of DND particles. We did not observe however an increase in rMSCs adhesion and growth on DND-modified PPHMDS surfaces compared to unmodified PPHMDS. When we studied alkaline phosphatase (ALP) activity, which is a major sign for early osteodifferentiation, we found the highest ALP activity on the PPHMDS/DND material, prepared by consequent deposition while on the other composite material ALP activity was the lowest. These results suggested that DND-modified materials were able to control osteodifferention in MSCs depending on the deposition approach. Modification of HMDS with DND particles by consequent plasma deposition seems to be a promising approach to produce biomaterials capable to guide stem cell differentiation toward osteoblasts and thus to be used in bone tissue engineering.

  14. Surface structure and oxidation reactivity of oil sand coke particles

    Energy Technology Data Exchange (ETDEWEB)

    Fairbridge, C.; Palmer, A.D.; Ng, S.H.; Furimsky, E.

    1987-05-01

    Fractions of particles of varying mean diameter were isolated from coke obtained from the fluid coking of Athabasca bitumen. Correlations were established between the rate of oxygen sorption and the apparent surface area as measured by carbon dioxide adsorption. The rate of oxygen sorption, r/sub o/, could be related to particle radius, R, by r/sub o/ varying with R/sup D/ T over a range of particle size where D is the fractal dimension of the coke. The existence of such correlations may be related to the iterative processes which form the particles. 14 refs., 5 figs., 2 tabs.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  16. Modification of the RTMTRACE program for numerical simulation of particle dynamics at racetrack microtrons with account of space charge forces

    International Nuclear Information System (INIS)

    Surma, I.V.; Shvedunov, V.I.

    1993-01-01

    The paper presents modification results of the program for simulation of particle dynamics in cyclic accelerators with RTMTRACE linear gap. The program was modified with regard for the effect of space charge effect on particle dynamics. Calculation results of particle dynamics in 1 MeV energy continuous-duty accelerator with 10 kw beam were used to develop continuous powerful commercial accelerator. 3 refs., 2 figs

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  18. Utilization of surface-treated rubber particles from waste tires

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F.G. [Argonne National Lab., IL (United States). Energy Systems Div.]|[Environmental Technologies Alternatives, Inc., Lima, OH (United States)

    1994-12-01

    During a 12-month program, the author successfully demonstrated commercial applications for surface-treated rubber particles in two major markets: footwear (shoe soles and components) and urethane-foam carpet underlay (padding). In these markets, he has clearly demonstrated the ease of using R-4080 and R-4030 surface-treated rubber particles in existing manufacturing plants and processes and have shown that the material meets or exceeds existing standards for performance, quality, and cost-effectiveness. To produce R-4080 and R-4030, vulcanized rubber, whole-tire material is finely ground to particles of nominal 80 and mesh size respectively. Surface treatment is achieved by reacting these rubber particles with chlorine gas. In this report, the author describes the actual test and evaluations of the participant companies, and identifies other potential end uses.

  19. Diffusion of particles on a fluctuating surface

    Czech Academy of Sciences Publication Activity Database

    Tarasenko, Alexander; Jastrabík, Lubomír

    2011-01-01

    Roč. 29, č. 5 (2011), s. 487-494 ISSN 0263-6174 R&D Projects: GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : kinetic Monte Carlo simulations * diffusion on a fluctuating surface Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.606, year: 2011

  20. Modification of bamboo surface by irradiation of ion beams

    International Nuclear Information System (INIS)

    Wada, M.; Nishigaito, S.; Flauta, R.; Kasuya, T.

    2003-01-01

    When beams of hydrogen ions, He + and Ar + were irradiated onto bamboo surface, gas release of hydrogen, water, carbon monoxide and carbon dioxide were enhanced. Time evolution of the gas emission showed two peaks corresponding to release of adsorbed gas from the surface by sputtering, and thermal desorption caused by the beam heating. The difference in etched depths between parenchyma lignin and vascular bundles was measured by bombarding bamboo surface with the ion beams in the direction parallel to the vascular bundles. For He + and Ar + , parenchyma lignin was etched more rapidly than vascular bundles, but the difference in etched depth decreased at a larger dose. In the case of hydrogen ion bombardment, vascular bundles were etched faster than parenchyma lignin and the difference in etched depth increased almost in proportion to the dose. The wettability of outer surface of bamboo was improved most effectively by irradiation of a hydrogen ion beam

  1. Modification of Ultra-High Vacuum Surfaces Using Free Radicals

    CERN Document Server

    Vorlaufer, G

    2002-01-01

    In ultra-high vacuum systems outgassing from vacuum chamber walls and desorption of surface adsorbates are usually the factors which determine pressure and residual gas composition. In particular in beam vacuum systems of accelerators like the LHC, where surfaces are exposed to intense synchrotron radiation and bombardment by energetic ions and electrons, surface properties like the molecular desorption yield or secondary electron yield can strongly influence the performance of the accelerator. Well-established treatment methods like vacuum bake-out or glow-discharge cleaning have been successfully applied in the past to condition ultra-high vacuum surfaces, but these methods are sometimes difficult to carry out, for example if the vacuum chambers are not accessible. In this work, an alternative treatment method is investigated. This method is based on the strong chemical reactivity of free radicals, electrically neutral fragments of molecules. Free radicals (in the case of this work, nitrogen and oxygen radi...

  2. Reducing ZnO nanoparticle cytotoxicity by surface modification.

    Science.gov (United States)

    Luo, Mingdeng; Shen, Cenchao; Feltis, Bryce N; Martin, Lisandra L; Hughes, Anthony E; Wright, Paul F A; Turney, Terence W

    2014-06-07

    Nanoparticulate zinc oxide (ZnO) is one of the most widely used engineered nanomaterials and its toxicology has gained considerable recent attention. A key aspect for controlling biological interactions at the nanoscale is understanding the relevant nanoparticle surface chemistry. In this study, we have determined the disposition of ZnO nanoparticles within human immune cells by measurement of total Zn, as well as the proportions of extra- and intracellular dissolved Zn as a function of dose and surface coating. From this mass balance, the intracellular soluble Zn levels showed little difference in regard to dose above a certain minimal level or to different surface coatings. PEGylation of ZnO NPs reduced their cytotoxicity as a result of decreased cellular uptake arising from a minimal protein corona. We conclude that the key role of the surface properties of ZnO NPs in controlling cytotoxicity is to regulate cellular nanoparticle uptake rather than altering either intracellular or extracellular Zn dissolution.

  3. Surface modification of UHMWPE with infrared femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-15

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

  4. Modification of carbon fiber surfaces via grafting with Meldrum's acid

    Science.gov (United States)

    Cuiqin, Fang; Jinxian, Wu; Julin, Wang; Tao, Zhang

    2015-11-01

    The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated in this work. The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid to create carboxylic functionalized surfaces. The surface functionalization effect was detected with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The XPS results showed that the relative content of carboxylic groups on carbon fiber surfaces was increased from initial 1.41% to 7.84%, however, that of carbonyl groups was decreased from 23.11% to 13.28% after grafting reaction. The SEM, AFM and TGA results indicated that the surfaces of carbon fibers neither etched nor generated coating. The tensile strength of carbon fibers was preserved after grafting reaction according to single fiber tensile strength tests. The fibers were well combined with matrix and the maximal interlaminar shear strength (ILSS) of carbon fiber/epoxy resin composites was sharply increased approximately 74% after functionalization. The effects of acetic acid and sonication on the degree of the surface functionalization were also studied.

  5. Multifunctional Surface Modification of Nanodiamonds Based on Dopamine Polymerization.

    Science.gov (United States)

    Zeng, Yun; Liu, Wenyan; Wang, Zheyu; Singamaneni, Srikanth; Wang, Risheng

    2018-04-03

    Surface functionalization of nanodiamonds (NDs), which is of great interest in advanced material and therapeutic applications, requires the immobilization of functional species, such as nucleic acids, bioprobes, drugs, and metal nanoparticles, onto NDs' surfaces to form stable nanoconjugates. However, it is still challenging to modify the surface of NDs due to the complexity of their surface chemistry and the low density of each functional group on the surfaces of NDs. In this work, we demonstrate a general applicable surface functionalization approach for the preparation of ND-based core-shell nanoconjugates using dopamine polymerization. By taking advantage of the universal adhesion and versatile reactivity of polydopamine, we have effectively conjugated DNA and silver nanoparticles onto NDs. Moreover, the catalytic activity of ND-supported silver nanoparticle was characterized by the reduction of 4-nitrophenol, and the addressability of NDs was tested through DNA hybridization that formed satellite ND-gold nanorod conjugation. This simple and robust method we have presented may significantly improve the capability for attaching various functionalities onto NDs and open up new platforms for applications of NDs.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  7. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.

    2012-01-08

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  8. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.; Liang, Cai; Giouroudi, Ioanna; Kosel, Jü rgen

    2012-01-01

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  9. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

  11. Atomic and molecular layer deposition for surface modification

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

  12. Photochemical surface modification of PP for abrasion resistance

    International Nuclear Information System (INIS)

    Bahners, Thomas; Haessler, Ruediger; Gao Shanglin; Maeder, Edith; Wego, Andreas; Schollmeyer, Eckhard

    2009-01-01

    The potential of a photo-chemical approach to increase the surface hardness of polypropylene (PP) has been studied. Using a 222 nm excimer lamp, fibers and film were irradiated in the presence of multi-functional substances diallylphthalate (DAP), tetraallyloxyethane (TAE), and pentaerithritoltriacylate (PETA) and characterized with regard to the resulting effect on abrasion resistance. AFM-based methods were employed to analyze thermo-mechanical surface properties. Nanoindentation and microthermal analyses of the outermost surface layers of UV treated fibers gave clear indications of an effective cross-linking of reactive substances present during irradiation. One may assume that the reactive media polymerize on top of the surface of the PP substrate and form a thin-layer. The abrasion resistance of the PP fibers was tested by applying stress through a rotating and axially oscillating roller of defined roughness and measuring the mass loss as a function of time. The abrasion resistance was found to be remarkably improved compared to the untreated fiber. Best effects were achieved using PETA as reactive substance. The experiments clearly showed the influence of processing conditions, namely with regard to homogeneous coverage of the substrate surface with the reactive medium.

  13. Surface modification of microfibrous materials with nanostructured carbon

    Energy Technology Data Exchange (ETDEWEB)

    Krasnikova, Irina V., E-mail: tokareva@catalysis.ru [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk 634050 (Russian Federation); Mishakov, Ilya V.; Vedyagin, Aleksey A. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk 634050 (Russian Federation); Bauman, Yury I. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk 630090 (Russian Federation); Korneev, Denis V. [State Research Center of Virology and Biotechnology VECTOR, Koltsovo, Novosibirsk Region 630559 (Russian Federation)

    2017-01-15

    The surface of fiberglass cloth, carbon and basalt microfibers was modified with carbon nanostructured coating via catalytic chemical vapor deposition (CCVD) of 1,2-dichloroethane. Incipient wetness impregnation and solution combustion synthesis (SCS) methods were used to deposit nickel catalyst on the surface of microfibrous support. Prepared NiO/support samples were characterized by X-ray diffraction analysis and temperature-programmed reduction. The samples of resulted hybrid materials were studied by means of scanning and transmission electron microscopies as well as by low-temperature nitrogen adsorption. The nature of the support was found to have considerable effect on the CCVD process peculiarities. High yield of nanostructured carbon with largest average diameter of nanofibers within the studied series was observed when carbon microfibers were used as a support. This sample characterized with moderate surface area (about 80 m{sup 2}/g after 2 h of CCVD) shows the best anchorage effect. Among the mineral supports, fiberglass tissue was found to provide highest carbon yield (up to 3.07 g/g{sub FG}) and surface area (up to 344 m{sup 2}/g) due to applicability of SCS method for Ni deposition. - Highlights: • The microfibers of different nature were coated with nanostructured carbon layer. • Features of CNF growth and characteristics of hybrid materials were studied. • Appropriate anchorage of CNF layer on microfiber’s surface was demonstrated.

  14. Simulation of liquid crystals. Disclinations and surface modification

    International Nuclear Information System (INIS)

    Downton, M.

    2001-01-01

    In this thesis we investigate the behaviour of molecular models liquid crystals in several different situations. Basic introductory material on liquid crystals and computer simulations is discussed in the first two chapters, we then discuss the research. The third chapter investigates the interaction between a liquid crystal and a modified surface. A confined system of hard spherocylinders in a slab geometry is examined. The surface consists of planar hard walls with elongated molecules grafted perpendicularly onto them. The concentration of grafted molecules is varied to give different surfaces. Several different behaviours are found including planar, homeotropic and tilted anchorings of the liquid crystal. Molecular dynamics simulations of a nematic liquid crystal in slab geometry with twisted boundary conditions are performed. By arranging the initial configuration suitably it is possible to create a simulation cell with two regions of opposite twist separated by a strength half disclination line. The properties of the line are examined both with and without an applied external field. Finally, we again examine the system of grafted molecules on a flat substrate using an atomistic model of both the liquid crystal and the surface molecules. Again the effect of varying the density of grafted molecules is found to change the anchoring characteristics of the surface; both homeotropic and planar anchorings are observed. (author)

  15. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Huang Sha [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Wang Yijuan [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Deng, Tianzheng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Jin Fang [Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi' an, 710032 (China); Liu Shouxin [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Zhang Yongjie [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Feng Feng [Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an 710038 (China); Jin Yan [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China)], E-mail: yanjin@fmmu.edu.cn

    2008-07-28

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 {mu}m) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering.

  16. Facile modification of gelatin-based microcarriers with multiporous surface and proliferative growth factors delivery to enhance cell growth

    International Nuclear Information System (INIS)

    Huang Sha; Wang Yijuan; Deng, Tianzheng; Jin Fang; Liu Shouxin; Zhang Yongjie; Feng Feng; Jin Yan

    2008-01-01

    The design of microcarriers plays an important role in the success of cell expansion. The present article provides a facile approach to modify the gelatin-based particles and investigates the feasibility of their acting as microcarriers for cell attachment and growth. Gelatin particles (150-320 μm) were modified by cryogenic treatment and lyophilization to develop the surface with the features of multiporous morphology and were incorporated with proliferative growth factors (bFGF) by adsorption during the post-preparation, which enables them to serve as microcarriers for cells amplification, together with the advantages of larger cell-surface contact area and capability of promoting cell propagation. The microstructure and release assay of the modified microcarriers demonstrated that the pores on surface were uniform and bFGF was released in a controlled manner. Through in vitro fibroblast culture, these features resulted in a prominent increase in the cell attachment rate and cell growth rate relative to the conditions without modification. Although the scanning electron microscopy and optical microscopy analysis results indicated that cells attached, spread, and proliferated on all the microcarriers, cell growth clearly showed a significant correlation with the multiporous structure of microcarriers, in particular on bFGF combined ones. These results validate our previous assumption that the facile modification could improve cell growth on the gelatin-based microcarriers obviously and the novel microcarriers may be a promising candidate in tissue engineering

  17. Modification of Textile Materials' Surface Properties Using Chemical Softener

    Directory of Open Access Journals (Sweden)

    Jurgita KOŽENIAUSKIENĖ

    2011-03-01

    Full Text Available In the present study the effect of technological treatment involving the processes of washing or washing and softening with chemical cationic softener "Surcase" produced in Great Britain on the surface properties of cellulosic textile materials manufactured from cotton, bamboo and viscose spun yarns was investigated. The changes in textile materials surface properties were evaluated using KTU-Griff-Tester device and FEI Quanta 200 FEG scanning electron microscope (SEM. It was observed that the worst hand properties and the higher surface roughness are observed of cotton materials if compared with those of bamboo and viscose materials. Also, it was shown that depending on the material structure the handle parameters of knitted materials are the better than the ones of woven fabrics.http://dx.doi.org/10.5755/j01.ms.17.1.249

  18. Continuous Natural Fiber Reinforced Thermoplastic Composites by Fiber Surface Modification

    Directory of Open Access Journals (Sweden)

    Patcharat Wongsriraksa

    2013-01-01

    Full Text Available Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. Therefore, intermediate material, which allows high impregnation during molding, has been investigated for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fiber alongside reinforcing fiber with braiding technique. This intermediate material has been called “microbraid yarn (MBY.” Moreover, it is well known that the interfacial properties between natural fiber and resin are low; therefore, surface treatment on continuous natural fiber was performed by using polyurethane (PU and flexible epoxy (FLEX to improve the interfacial properties. The effect of surface treatment on the mechanical properties of continuous natural fiber reinforced thermoplastic composites was examined. From these results, it was suggested that surface treatment by PU with low content could produce composites with better mechanical properties.

  19. Biomolecular modification of zirconia surfaces for enhanced biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Shih-Kuang; Hsu, Hsueh-Chuan [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan, ROC (China); Ho, Wen-Fu [Department of Chemical and Materials Engineering, National University of Kaohsiung, Taiwan, ROC (China); Yao, Chun-Hsu [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 40402, Taiwan, ROC (China); Chang, Pai-Ling [Taoyuan General Hospital, Taoyuan 33004, Taiwan, ROC (China); Wu, Shih-Ching, E-mail: scwu@ctust.edu.tw [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taichung 40601, Taiwan, ROC (China)

    2014-12-01

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

  20. Laser surface modification of Ti implants to improve osseointegration

    International Nuclear Information System (INIS)

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

    2007-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  4. Chemical Modification of Semiconductor Surfaces for Molecular Electronics.

    Science.gov (United States)

    Vilan, Ayelet; Cahen, David

    2017-03-08

    Inserting molecular monolayers within metal/semiconductor interfaces provides one of the most powerful expressions of how minute chemical modifications can affect electronic devices. This topic also has direct importance for technology as it can help improve the efficiency of a variety of electronic devices such as solar cells, LEDs, sensors, and possible future bioelectronic ones. The review covers the main aspects of using chemistry to control the various aspects of interface electrostatics, such as passivation of interface states and alignment of energy levels by intrinsic molecular polarization, as well as charge rearrangement with the adjacent metal and semiconducting contacts. One of the greatest merits of molecular monolayers is their capability to form excellent thin dielectrics, yielding rich and unique current-voltage characteristics for transport across metal/molecular monolayer/semiconductor interfaces. We explain the interplay between the monolayer as tunneling barrier on the one hand, and the electrostatic barrier within the semiconductor, due to its space-charge region, on the other hand, as well as how different monolayer chemistries control each of these barriers. Practical tools to experimentally identify these two barriers and distinguish between them are given, followed by a short look to the future. This review is accompanied by another one, concerning the formation of large-area molecular junctions and charge transport that is dominated solely by molecules.

  5. Modification of polyvinyl alcohol surface properties by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Pukhova, I.V., E-mail: ivpuhova@mail.ru [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Kurzina, I.A. [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Savkin, K.P. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Laput, O.A. [National Research Tomsk Polytechnic University, 30 Lenin Ave, Tomsk 634050 (Russian Federation); Oks, E.M. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation)

    2017-05-15

    We describe our investigations of the surface physicochemical properties of polyvinyl alcohol modified by silver, argon and carbon ion implantation to doses of 1 × 10{sup 14}, 1 × 10{sup 15} and 1 × 10{sup 16} ion/cm{sup 2} and energies of 20 keV (for C and Ar) and 40 keV (for Ag). Infrared spectroscopy (IRS) indicates that destructive processes accompanied by chemical bond (−C=O) generation are induced by implantation, and X-ray photoelectron spectroscopy (XPS) analysis indicates that the implanted silver is in a metallic Ag3d state without stable chemical bond formation with polymer chains. Ion implantation is found to affect the surface energy: the polar component increases while the dispersion part decreases with increasing implantation dose. Surface roughness is greater after ion implantation and the hydrophobicity increases with increasing dose, for all ion species. We find that ion implantation of Ag, Ar and C leads to a reduction in the polymer microhardness by a factor of five, while the surface electrical resistivity declines modestly.

  6. Modification of surface properties of LLDPE by water plasma discharge

    International Nuclear Information System (INIS)

    Chantara Thevy Ratnam; Hill, D.J.T.; Firas Rasoul; Whittaker, A.K.; Imelda Keen

    2007-01-01

    Linear low density polyethylene (LLDPE) surface was modified by water plasma treatment. The LLDPE surface was treated at 10 and 20 W discharge power at various exposure times. A laboratory scale Megatherm radio frequency (RF) plasma apparatus that operates at 27 MHz was used to generate the water plasmas. The changes in chemical structure of the LLDPE polymeric chain upon plasma treatment were characterized by FTIR and XPS techniques. The selectivity of trifluoroacetic anhydride (TFAA) toward hydroxyl groups is used to quantify the hydroxyl groups formed on the polymer surface upon plasma treatment. After exposition to the plasma discharge a decline in water contact angle were observed. FTIR and XPS measurements indicate an oxidation of degraded polymeric chains and creation of hydroxyl, carbonyl, ether, ester and carboxyl groups. Chemical derivatization with TFAA of water plasma treated polymer surfaces has shown that under the conditions employed, a very small (less than 5%) of the oxygen introduced by the water plasma treatment was present as hydroxyl group. (Author)

  7. Mapping physicochemical surface modifications of flame-treated polypropylene

    Directory of Open Access Journals (Sweden)

    S. Farris

    2014-04-01

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

  8. Atmospheric pressure plasma surface modification of carbon fibres

    DEFF Research Database (Denmark)

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

    2008-01-01

    Carbon fibres are continuously treated with dielectric barrier discharge plasma at atmospheric pressure in various gas conditions for adhesion improvement in mind. An x-ray photoelectron spectroscopic analysis indicated that oxygen is effectively introduced onto the carbon fibre surfaces by He, He...

  9. Modification of metallic surfaces by positive ion bombardment

    International Nuclear Information System (INIS)

    Rickards C, J.

    1989-01-01

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

  10. Ion beam induced optical and surface modification in plasmonic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Udai B., E-mail: udaibhansingh123@gmail.com; Gautam, Subodh K.; Kumar, Sunil; Hooda, Sonu; Ojha, Sunil; Singh, Fouran

    2016-07-15

    In present work, ion irradiation induced nanostructuring has been exploited as an efficient and effective tool for synthesis of coupled plasmonics nanostructures by using 1.2 MeV Xe ions on Au/ZnO/Au system deposited on glass substrate. The results are correlated on the basis of their optical absorption, surface morphologies and enhanced sensitivity of evolved phonon modes by using UV Visible spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy (RS), respectively. Optical absorbance spectra of plasmonic nanostructures (NSs) show a decrease in band gap, which may be ascribed to the formation of defects with ion irradiation. The surface morphology reveals the formation of percolated NSs upon ion irradiation and Rutherford backscattering spectrometry (RBS) study clearly shows the formation of multilayer system. Furthermore, RS measurements on samples are studied to understand the enhanced sensitivity of ion irradiation induced phonon mode at 573 cm{sup −1} along with other modes. As compared to pristine sample, a stronger and pronounced evolution of these phonon modes is observed with further ion irradiation, which indicates localized surface plasmon results with enhanced intensity of phonon modes of Zinc oxide (ZnO) material. Thus, such plasmonic NSs can be used as surface enhanced Raman scattering (SERS) substrates.

  11. Modification of Pawlow's thermodynamical model for the melting of small single-component particles

    Science.gov (United States)

    Barybin, Anatoly; Shapovalov, Victor

    2011-02-01

    A new approach to the melting of small particles is proposed to modify the known Pawlow's model by taking into account the transfer of material from solid spherical particles to liquid ones through a gas phase. Thermodynamical analysis gives rise to a differential equation for the melting point Tm involving such size-dependent and temperature-dependent parameters of a material as the surface tensions σs(l ), molar heat of fusion ΔHm and molar volumes vs(l ). Solution of this equation has shown that all the limiting cases for size-independent situations coincide with results known in the literature and our analysis of size-dependent situations gives results close to the experimental data previously obtained by other authors for some metallic particles.

  12. Surface Modification of Porous Titanium Granules for Improving Bioactivity.

    Science.gov (United States)

    Karaji, Zahra Gorgin; Houshmand, Behzad; Faghihi, Shahab

    The highly porous titanium granules are currently being used as bone substitute material and for bone tissue augmentation. However, they suffer from weak bone bonding ability. The aim of this study was to create a nanostructured surface oxide layer on irregularly shaped titanium granules to improve their bioactivity. This could be achieved using optimized electrochemical anodic oxidation (anodizing) and heat treatment processes. The anodizing process was done in an ethylene glycol-based electrolyte at an optimized condition of 60 V for 3 hours. The anodized granules were subsequently annealed at 450°C for 1 hour. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD) were used to characterize the surface structure and morphology of the granules. The in vitro bioactivity of the samples was evaluated by immersion of specimens in simulated body fluid (SBF) for 1, 2, and 3 weeks. The human osteoblastic sarcoma cell line, MG63, was used to evaluate cell viability on the samples using dimethylthiazol-diphenyl tetrazolium bromide (MTT) assay. The results demonstrated the formation of amorphous nanostructured titanium oxide after anodizing, which transformed to crystalline anatase and rutile phases upon heat treatment. After immersion in SBF, spherical aggregates of amorphous calcium phosphate were formed on the surface of the anodized sample, which turned into crystalline hydroxyapatite on the surface of the anodized annealed sample. No cytotoxicity was detected among the samples. It is suggested that anodic oxidation followed by heat treatment could be used as an effective surface treatment procedure to improve bioactivity of titanium granules implemented for bone tissue repair and augmentation.

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

    Science.gov (United States)

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

    2011-01-04

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

  14. Modification of Ti6Al4V surface by diazonium compounds

    Science.gov (United States)

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

    2018-02-01

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

  15. Copper circuit patterning on polymer using selective surface modification and electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Jin [Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Ko, Tae-Jun [Institute for Multidisciplinary Convergence of Materials, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Yoon, Juil [Department of Mechanical Systems Engineering, Hansung University, Seoul 136-792 (Korea, Republic of); Moon, Myoung-Woon [Institute for Multidisciplinary Convergence of Materials, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Oh, Kyu Hwan [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Han, Jun Hyun, E-mail: jhhan@cnu.ac.kr [Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2017-02-28

    Highlights: • A new simple two step method for the pattering of Cu circuits on PET substrate was proposed. • The simple patterning of the high adhesive Cu circuits was achieved by plasma treatment using a patterned mask coated with a catalyst material. • The high adhesive strength of Cu circuits was due to the nanostructure formed by oxygen plasma treatment. - Abstract: We have examined a potential new and simple method for patterning a copper circuit on PET substrate by copper electroless plating, without the pretreatment steps (i.e., sensitization and activation) for electroless plating as well as the etching processes of conventional circuit patterning. A patterned mask coated with a catalyst material, Ag, for the reduction of Cu ions, is placed on a PET substrate. Subsequent oxygen plasma treatment of the PET substrate covered with the mask promotes the selective generation of anisotropic pillar- or hair-like nanostructures coated with co-deposited nanoparticles of the catalyst material on PET. After oxygen plasma treatment, a Cu circuit is well formed just by dipping the plasma-treated PET into a Cu electroless plating solution. By increasing the oxygen gas pressure in the chamber, the height of the nanostructures increases and the Ag catalyst particles are coated on not only the top but also the side surfaces of the nanostructures. Strong mechanical interlocking between the Cu circuit and PET substrate is produced by the large surface area of the nanostructures, and enhances peel strength. Results indicate this new simple two step (plasma surface modification and pretreatment-free electroless plating) method can be used to produce a flexible Cu circuit with good adhesion.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jocić Dragan

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

  2. Surface modification of nanoporous alumina membranes by plasma polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Losic, Dusan; Cole, Martin A; Dollmann, Bjoern; Vasilev, Krasimir; Griesser, Hans J [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)], E-mail: dusan.losic@unisa.edu.au

    2008-06-18

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

  3. Surface modification for bonding between amalgam and orthodontic brackets.

    Science.gov (United States)

    Wongsamut, Wittawat; Satrawaha, Sirichom; Wayakanon, Kornchanok

    2017-01-01

    Testing of methods to enhance the shear bond strength (SBS) between orthodontic metal brackets and amalgam by sandblasting and different primers. Three hundred samples of amalgam restorations (KerrAlloy ® ) were prepared in self-cured acrylic blocks, polished, and divided into two groups: nonsandblasted and sandblasted. Each group was divided into five subgroups with different primers used in surface treatment methods, with a control group of bonded brackets on human mandibular incisors. Following the surface treatments, mandibular incisor brackets (Unitek ® ) were bonded on the amalgam with adhesive resin (Transbond XT ® ). The SBS of the samples was tested. The adhesive remnant index (ARI) and failure modes were then determined under a stereo-microscope. Two-way analysis of variance, Chi-square, and Kruskal-Wallis tests were performed to calculate the correlations between and among the SBS and ARI values, the failure modes, and surface roughness results. There were statistically significant differences of SBS among the different adhesive primers and sandblasting methods ( P 0.05). Using adhesive primers with sandblasting together effectively enhances the SBS between orthodontic metal brackets and amalgam. The two primers with the ingredient methacryloxydecyl dihydrogen phosphate (MDP) monomer, Alloy Primer ® and Assure Plus ® , were the most effective. Including sandblasting in the treatment is essential to achieve the bonding strength required.

  4. Surface modification of nanoporous alumina membranes by plasma polymerization

    International Nuclear Information System (INIS)

    Losic, Dusan; Cole, Martin A; Dollmann, Bjoern; Vasilev, Krasimir; Griesser, Hans J

    2008-01-01

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

  5. Charged particle discrimination with silicon surface barrier detectors

    International Nuclear Information System (INIS)

    Coote, G.E.; Pithie, J.; Vickridge, I.C.

    1996-01-01

    The application for materials analysis of nuclear reactions that give rise to charged particles is a powerful surface analytical and concentration depth profiling technique. Spectra of charged particles, with energies in the range 0.1 to 15 MeV, emitted from materials irradiated with beams of light nuclei such as deuterons are measured with silicon surface barrier detectors. The spectra from multi-elemental materials typically encountered in materials research are usually composed of an overlapping superposition of proton, alpha, and other charged particle spectra. Interpretation of such complex spectra would be simplified if a means were available to electronically discriminate between the detector response to the different kinds of charged particle. We have investigated two methods of discriminating between different types of charged particles. The fast charge pulses from a surface barrier detector have different shapes, depending on the spatial distribution of energy deposition of the incident particle. Fast digitisation of the pulses, followed by digital signal processing provides one avenue for discrimination. A second approach is to use a thin transmission detector in front of a thick detector as a detector telescope. For a given incident energy, different types of charged particles will lose different amounts of energy in the thin detector, providing an alternative means of discrimination. We show that both approaches can provide significant simplification in the interpretation of charged particle spectra in practical situations, and suggest that silicon surface barrier detectors having graded electronic properties could provide improved discrimination compared to the current generation of detectors having homogeneous electronic properties. (author).12 refs., 2 tabs., 28 figs

  6. Surface modification of TiO2 nanotubes by grafting with APTS coupling agents

    Science.gov (United States)

    Phan Duong, Hong; Le, Minh Duc; Dao, Hung Cuong; Chen, Chia-Yun

    2017-10-01

    Titanium dioxide nanotubes (TNTs) have been considered the promising nanostructures employed for many practical applications such as biomedical, photonic and optoelectronic devices. Nevertheless, strong aggregation of TNTs within various aqueous media significantly hindered their practical utilizations and the capability of dispersing TNTs in the desired solvents are urgent to be improved. Therefore, in this study, the methodic investigations have been performed on the grafted modification of 3-aminopropyl triethoxysilane (APTS) on the surfaces of synthesized TNTs. A preliminary study was carried out to evaluate the influences of key parameters, including the concentrations of coupling agents, temperatures and the reaction durations, on the grafting efficiency of the aminosilane using Statistical design of experiments (DoE) methodology. TNTs with approximately 10-20 nm in diameter were prepared with the controlled hydrothermal treatment of commercialized P25 particles. The obtained products were revealed by the modern physicochemical systems including x-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. The additions of silane agent, reaction temperature and time have been adjusted to reveal the influences of the grafting efficiency (from 2.5 to 7.8 wt %) by thermal gravimetric analysis (TGA). Analysis of Fourier transform infrared spectroscopy (FTIR) has confirmed the successful link of Ti-O-Si chemical bonds on the grafted TNTs.

  7. 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...

  8. Plasma–Surface Interactions Under High Heat and Particle Fluxes

    Directory of Open Access Journals (Sweden)

    Gregory De Temmerman

    2013-01-01

    Full Text Available The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface interactions studies under those very harsh conditions. While the ion energies on the divertor surfaces of a fusion device are comparable to those used in various plasma-assited deposition and etching techniques, the ion (and energy fluxes are up to four orders of magnitude higher. This large upscale in particle flux maintains the surface under highly non-equilibrium conditions and bring new effects to light, some of which will be described in this paper.

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

    Science.gov (United States)

    Nady, Norhan

    2016-04-18

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-06-01

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

  12. Engineering Particle Surface Chemistry and Electrochemistry with Atomic Layer Deposition

    Science.gov (United States)

    Jackson, David Hyman Kentaro

    Atomic layer deposition (ALD) is a vapor phase thin film coating technique that relies on sequential pulsing of precursors that undergo self-limited surface reactions. The self- limiting reactions and gas phase diffusion of the precursors together enable the conformal coating of microstructured particles with a high degree of thickness and compositional control. ALD may be used to deposit thin films that introduce new functionalities to a particle surface. Examples of new functionalities include: chemical reactivity, a mechanically strong protective coating, and an electrically resistive layer. The coatings properties are often dependent on the bulk properties and microstructure of the particle substrate, though they usually do not affect its bulk properties or microstructure. Particle ALD finds utility in the ability to synthesize well controlled, model systems, though it is expensive due to the need for costly metal precursors that are dangerous and require special handling. Enhanced properties due to ALD coating of particles in various applications are frequently described empirically, while the details of their enhancement mechanisms often remain the focus of ongoing research in the field. This study covers the various types of particle ALD and attempts to describe them from the unifying perspective of surface science.

  13. Studies on the surface modification of diatomite with polyethyleneimine and trapping effect of the modified diatomite for phenol

    International Nuclear Information System (INIS)

    Gao Baojiao; Jiang Pengfei; An Fuqiang; Zhao Shuying; Ge Zhen

    2005-01-01

    The adsorption isotherm of polyethyleneimine (PEI) on diatomite was studied using UV spectrophotometry, the surface of diatomite was modified with polyethyleneimine by using impregnation method, and the trapping behavior of the modified diatomite for phenol was investigated by using 4-aminoantipyrine (4-AAP) spectrophotometric method. The experiment results show that negatively charged diatomite particles have very strong absorption effect for cationic macromolecule PEI, the adsorption isotherm fits in Freundlich equation. The character that there is a maximum value after intitial sharp increase of adsorption capacity on the adsorption curve indicates that there is strong affinity between diatomite particles and polyethyleneimine macromolecules, and it attributes to the strong electrostatic interaction. After modification with PEI, the electric property of diatomite particle surface changes essentially, and the isoelectric point of diatomite particles moves from pH 2.0 to 10.5. In acidic solution, phenol exists as molecular state, and the modified diatomite particles adsorb phenol through hydrogen bond interaction. However, the hydrogen bond interaction between nitrogen atoms on PEI chains and phenol is weaker because of high degree of protonation of polyethyleneimine macromolecules, so the adsorption quantity is lower. In basic solution, phenol exists as negative benzene-oxygen ion, and the modified diatomite particles adsorb phenol through electrostatic interaction. However, the electrostatic interaction between PEI and negative benzene-oxygen ion is very weak because of low degree of protonation of polyethyleneimine macromolecules, so the adsorption quantity is much lower. The modified diatomite particles produce very strong trapping effect for phenol in neutral aqueous solution via the cooperating of strong electrostatic interaction and hydrogen bond interaction, and the saturated adsorption capacity can attain to 92 mg g -1

  14. Surface modification of calcium–copper hydroxyapatites using polyaspartic acid

    International Nuclear Information System (INIS)

    Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen; Debbabi, Mongi

    2013-01-01

    Highlights: ► The reaction of polyaspartic acid with calcium hydroxyapatite and mixed calcium–copper hydroxyapatite is tested. ► Chemical analysis shows that the presence of copper in the apatitic structure increases the reactivity of the apatite surface. ► X-ray powder analysis shows the conservation of unique crystalline phase of hydroxyapatite after copper incorporation and/or PASP acid reacting. ► IR spectra show the formation of the formation of organometallic bond M-O-C (M=Ca or Cu) on the apatitic surface. ► Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) indicated that the texture surface was changed by the grafting. - Abstract: Mixed calcium–copper hydroxyapatite (Ca–CuHAp), with general formula Ca (10−x) Cu x (PO 4 ) 6 (OH) 2 , where 0 ≤ x ≤ 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca–CuHAp–PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (P-OH) band of (HPO 4 ) 2− groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

  15. Surface modification of calcium-copper hydroxyapatites using polyaspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Debbabi, Mongi, E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer The reaction of polyaspartic acid with calcium hydroxyapatite and mixed calcium-copper hydroxyapatite is tested. Black-Right-Pointing-Pointer Chemical analysis shows that the presence of copper in the apatitic structure increases the reactivity of the apatite surface. Black-Right-Pointing-Pointer X-ray powder analysis shows the conservation of unique crystalline phase of hydroxyapatite after copper incorporation and/or PASP acid reacting. Black-Right-Pointing-Pointer IR spectra show the formation of the formation of organometallic bond M-O-C (M=Ca or Cu) on the apatitic surface. Black-Right-Pointing-Pointer Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) indicated that the texture surface was changed by the grafting. - Abstract: Mixed calcium-copper hydroxyapatite (Ca-CuHAp), with general formula Ca{sub (10-x)}Cu{sub x}(PO{sub 4}){sub 6}(OH){sub 2}, where 0 {<=} x {<=} 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca-CuHAp-PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (P-OH) band of (HPO{sub 4}){sup 2-} groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

  16. 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.

  17. Ion beam modification of surfaces for biomedical applications

    International Nuclear Information System (INIS)

    Sommerfeld, Jana

    2014-01-01

    Human life expectancy increased significantly within the last century. Hence, medical care must ever be improved. Optimizing artificial replacements such as hip joints or stents etc. is of special interest. For this purpose, new materials are constantly developed or known ones modified. This work focused on the possibility to change the chemistry and topography of biomedically relevant materials such as diamond-like carbon (DLC) and titanium dioxide (TiO 2 ) by means of ion beam irradiation. Mass-separated ion beam deposition was used in order to synthesize DLC layers with a high sp 3 content (> 70%), a sufficiently smooth surface (RMS<1 nm) and a manageable film thickness (50 nm). The chemistry of the DLC layers was changed by ion beam doping with different ion species (Ag,Ti) and concentrations. Additionally, the surface topography of silicon and titanium dioxide was altered by ion beam irradiation under non-perpendicular angle of incidence. The created periodic wave structures (so-called ripples) were characterized and their dependency on the ion energy was investigated. Moreover, ripples on silicon were covered with a thin DLC layer in order to create DLC ripples. The biocompatibility of all samples was investigated by adsorption experiments. For this purpose, human plasma fibrinogen (HPF) was used due to its ambiphilic character, which allows the protein to assume different conformations on materials with different hydrophilicities. Moreover, HPF is a crucial factor in the blood coagulation process. This work comes to the conclusion that the interaction of both, the surface chemistry and topography, has a strong influence on the adsorption behavior of HPF and thus the biocompatibility of a material. Both factors can be specifically tuned by means of ion beam irradiation.

  18. Radiative decay of surface plasmons on nonspherical silver particles

    International Nuclear Information System (INIS)

    Little, J.W.; Ferrell, T.L.; Callcott, T.A.; Arakawa, E.T.

    1982-01-01

    We have studied the radiation emitted by electron-bombarded silver particles. Electron micrographs have shown that the particles, obtained by heating thin (5 nm) silver films, were oblate (flattened) with minor axes aligned along the substrate normal. The characteristic wavelength obtained by bombarding these particles with 15-keV electrons was found to vary with angle of photon emission. We have modeled this wavelength shift as a result of the mixture of radiation from dipole and quadrupole surface-plasmon oscillations on oblate spheroids. Experimental observations of the energy, polarization, and angular distribution of the emitted radiation are in good agreement with theoretical calculations

  19. Ultrasound enhanced plasma surface modification at atmospheric pressure

    DEFF Research Database (Denmark)

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

    2012-01-01

    Efficiency of atmospheric pressure plasma treatment can be highly enhanced by simultaneous high power ultrasonic irradiation onto the treating surface. It is because ultrasonic waves with a sound pressure level (SPL) above ∼140 dB can reduce the thickness of a boundary gas layer between the plasma...... arc at atmospheric pressure to study adhesion improvement. The effect of ultrasonic irradiation with the frequency diapason between 20 and 40 kHz at the SPL of ∼150 dB was investigated. After the plasma treatment without ultrasonic irradiation, the wettability was significantly improved...

  20. 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. ...

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  2. Low-energy particle interaction at carbon nanowalls on W surface

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, N., E-mail: nozomi.tanaka@ppl2.qse.tohoku.ac.j [Tohoku University, Aramaki 6-01-2, Aoba, Sendai 980-8579 (Japan); Yamaoka, H. [Harima Institute, RIKEN (The Institute of Physical and Chemical Research), Hyogo 679-5148 (Japan); Nishiura, M.; Tsumori, K. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Nagamura, T.; Sasao, M. [Tohoku University, Aramaki 6-01-2, Aoba, Sendai 980-8579 (Japan); Kenmotsu, T. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Matsumoto, Y. [Tokushima Bunri University, Yamashiro, Tokushima 770-8514 (Japan); Wada, M. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2009-06-15

    We measured the characteristics of the reflected particles from a carbon nanowall (CNW) deposited on a W surface following the injection of 1-2 keV H{sup +} and O{sup +} ions. The reflected ion energies and intensities indicated a contribution from multiple scattering in the target. The reflection angular dependence of the reflected ion intensities reached the maximum around the mirror angle and showed a sharp distribution, which may be attributable to the effect due to the aligned structure of the CNW. The energies and intensities of the reflected ions decreased with the time of ion bombardment. The intensities and energies of the reflected ions were, however, recovered to some degree by baking the sample, indicating the surface modification due to retention of the injected particles during the injection. We used the Monte Carlo simulation code ACAT (Atomic Collision in Amorphous Target) to study these processes theoretically and the calculated results supported the experimental results.

  3. Rapid modification of urban land surface temperature during rainfall

    Science.gov (United States)

    Omidvar, H.; Bou-Zeid, E.; Song, J.; Yang, J.; Arwatz, G.; Wang, Z.; Hultmark, M.; Kaloush, K.

    2017-12-01

    We study the runoff dynamics and heat transfer over urban pavements during rainfall. A kinematic wave approach is combined with heat storage and transfer schemes to develop a model for impervious (with runoff) and pervious (without runoff) pavements. The resulting framework is a numerical prognostic model that can simulate the temperature fields in the subsurface and runoff layers to capture the rapid cooling of the surface, as well as the thermal pollution advected in the runoff. Extensive field measurements were then conducted over experimental pavements in Arizona to probe the physics and better represent the relevant processes in the model, and then to validate the model. The experimental data and the model results were in very good agreements, and their joint analysis elucidated the physics of the rapid heat transfer from the subsurface to the runoff layer. Finally, we apply the developed model to investigate how the various hydrological and thermal properties of the pavements, as well as ambient environmental conditions, modulate the surface and runoff thermal dynamics, what is the relative importance of each of them, and how we can apply the model mitigate the adverse impacts of urbanization.

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

    Science.gov (United States)

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Evans, P.J.; Hyvarinen, J.; Samandi, M.

    1995-01-01

    The wear properties of AISI 316 austenitic stainless steel implanted with Ti were investigated for ion doses in the range (2.3-5.4)x10 16 ionscm -2 and average ion energies of 60 and 90keV. The implanted layer was examined by Rutherford backscattering, from which the retained doses were determined, and glow discharge optical emission spectroscopy. Following implantation, the surface microhardness was observed to increase with the greatest change occurring at higher ion energy. Pin-on-disc wear tests and associated friction measurements were also performed under both dry and lubricated conditions using applied loads of 2N and 10N. In the absence of lubrication, breakthrough of the implanted layer occurred after a short sliding time; only for a dose of 5.1x10 16 ionscm -2 implanted at an average energy of 90keV was the onset of breakthrough appreciably delayed. In contrast, the results of tests with lubrication showed a more gradual variation, with the extent of wear decreasing with implant dose at both 2N and 10N loads. Finally, the influence of Ti implantation on possible wear mechanisms is discussed in the light of information provided by several surface characterization techniques. ((orig.))

  6. Hot zirconium cathode sputtered layers for useful surface modification

    International Nuclear Information System (INIS)

    Duckworth, R.G.

    1986-01-01

    It has been found that multilayer zirconium based sputtered coatings can greatly improve the wear properties of a wide variety of mechanical components, machine tools, and metal surfaces. Although a hot (approximately 1000 0 C) cathode is employed, temperature sensitive components can be beneficially treated, and for precision parts a total coating thickness of only 0.5μm is often perfectly effective. Even at the highest coating rates substrate temperatures are below 300 0 C. For the corrosion protection of less well finished surfaces thicker layers are usually required and it is important that relatively stress free layers are produced. The authors employed a variety of tailored zirconium/zirconium nitride/zirconium oxide mixed layers to solve a number of tribological problems for some 5 or 6 years. However, it is only recently that they designed, built, and commissioned rapid cycle, multiple cathode, load-lock plant for economic production of such coatings. This paper provides an introduction to this method of depositing pure zirconium and pure synthetic zirconium nitride films

  7. Interfacing biomembrane mimetic polymer surfaces with living cells - Surface modification for reliable bioartificial liver

    International Nuclear Information System (INIS)

    Iwasaki, Yasuhiko; Takami, Utae; Sawada, Shin-ichi; Akiyoshi, Kazunari

    2008-01-01

    The surface design used for reducing nonspecific biofouling is one of the most important issues for the fabrication of medical devices. We present here a newly synthesized a carbohydrate-immobilized phosphorylcholine polymer for surface modification of medical devices to control the interface with living cells. A random copolymer composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate (BMA), and 2-lactobionamidoethyl methacrylate (LAMA) was synthesized by conventional radical polymerization. The monomer feeding ratio in the copolymer was adjusted to 24/75/1 (MPC/BMA/LAMA). The copolymer (PMBL1.0) could be coated by solvent evaporation from an ethanol solution. Cells of the human hepatocellular liver carcinoma cell line (HepG2) having asialoglycoprotein receptors (ASGPRs) were seeded on PMBL1.0 or poly(BMA) (PBMA)-coated PET plates. On PBMA, many adherent cells were observed and were well spread with monolayer adhesion. HepG2 adhesion was observed on PMBL1.0 because the cell has ASGPRs. Furthermore, some of the cells adhering to PMBL1.0 had a spheroid formation and similarly shaped spheroids were scattered on the surface. According to confocal laser microscopic observation after 96 h cultivation, it was found that albumin production preferentially occurred in the center of the spheroid. The albumin production of the cells that adhered to PBMA was sparse. The amount of albumin production per unit cell that adhered to PMBL1.0 was determined by ELISA and was significantly higher than that which adhered to PBMA. Long-term cultivation of HepG2 was also performed using hollow fiber mini-modules coated with PMBL1.0. The concentration of albumin produced from HepG2 increased continuously for one month. In the mini-module, the function of HepG2 was effectively preserved for that period. On the hollow fiber membrane, spheroid formation of HepG2 cells was also observed. In conclusion, PMBL1.0 can provide a suitable surface for the cultivation of

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

    Directory of Open Access Journals (Sweden)

    Mukhopadhyay Subhadeep

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Fang Jiang

    2012-01-01

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

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

    International Nuclear Information System (INIS)

    Verma, Pallavi; Maire, Pascal; Novak, Petr

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-01

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

  12. Turbulence modification due to bubbles and particles in dispersed two-phase upflows in a vertical pipe

    International Nuclear Information System (INIS)

    Hosokawa, Shigeo; Tomiyama, Akio

    1999-01-01

    One of the key issues in two-phase turbulence modeling is the turbulence modification due to the momentum exchange between the dispersed and continuous phases. As for the gas-liquid two-phase flows in vertical pipes, Serizawa and Kataoka carried out detailed measurement of turbulence intensity and detected the turbulence modification. Gore and Crowe pointed out that the modification is well correlated with the ratio of a particle diameter to a turbulence length scale (d/l t ). However the modification may depend on not only the length scales but also the eddy viscosities of shear-induced and particle-induced turbulence. Hosokawa et al. proposed the ratio φ of the eddy viscosity induced by a dispersed phase to the shear-induced eddy viscosity and confirmed that measured turbulence modification was well correlated with φ for a gas-solid two-phase flow. In this study, we examine whether or not φ is also applicable to gas-liquid and solid-liquid two-phase dispersed upflows in vertical pipes. Using the eddy viscosity ratio instead of d/l t , we could obtain much better correlation. The critical point at which no modification occurred was close to φ = 1, irrespective of a type of a two-phase dispersed flow. Consequently, we could confirm that the eddy viscosity ratio is a more appropriate parameter for correlating the turbulent modification than the conventional critical parameter d/l t . (author)

  13. 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.

  14. Surface Modifications of Polymers Induced by Heavy Ions Grafting

    Energy Technology Data Exchange (ETDEWEB)

    Mazzei, R O; Lombardo, J; Camporotondi, D; Tadey, D; Bermudez, G G [National Atomic Energy Commission, Ezeiza Atomic Centre, Ezeiza (Argentina)

    2012-09-15

    Polymer surfaces are modified by the application of swift heavy ions etching and grafting procedures. The residual active sites produced by heavy ion beams, remaining after the etching process, were used to start the grafting process. In order to produce tracks on foils of poly(vinylidene fluoride) (PVDF) they were irradiated with {sup 208}Pb of 25.62 MeV/n or with 115 MeV Cl ions. Moreover, foils of polypropylene (PP) were irradiated with {sup 208}Pb of 25.62 MeV/n. Then, they were etched and grafted with N-isopropylacrylamide (NIPAAm) monomers or with acrylic acid (AAc) monomers, respectively. The replica method allowed the observation of the shape of the grafted tracks using transmission electron microscopy (TEM). In addition NIPAAm grafted foils were analyzed using Fourier transform infrared spectroscopy (FTIR). The sulfonation procedure (methodology previously described for perfluorated polymers) was applied on grafted PVDF. A new method is described to produce a thin layer of poly-acrylic-acid (membranes) that grows on the surface of PVDF foils implanted by an Ar{sup +} beam with energies between 30-150 keV. Different combinations of monomers in water solutions were used such as: acrylic acid (AAc); acrylic acid-glycidyl methacrylate (AAc-GMA); acrylic acid-styrene (AAc-S); acrylic acid-N-isopropyl acrylamide (AAc-NIPAAm) and acrylic acid-N-isopropyl acrylamide - glycidyl methacrylate (AAc-NIPAAm-GMA). The experimental results show that for particular values of: ion fluence and energy, AAc concentration, sulphuric acid and PVDF polymorphous (alpha or beta) a huge percentage of grafting was obtained. At certain point of the grafting process the development of the PolyAAc-Xmonomer produce a detachment from the irradiated substrate and continue its grafting outside it. This method produces a membrane that is an increased replica of the original implanted surface. Finally, PVDF films implanted by an Ar{sup +} beam with energies about 100 keV and a fluence of 10

  15. 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.

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

    Science.gov (United States)

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

    2015-03-01

    Artificial femur stem of 316L stainless steel was fabricated by investment casting using vacuum induction melting. Different surface treatments: mechanical polishing, thermal oxidation and immersion in alkaline solution were applied. Thicker hydroxyapatite (HAP) layer was formed in the furnace-oxidized samples as compared to the mechanically polished ones. The alkaline treatment enhanced the precipitation of HAP on the samples. It was also observed that the HAP precipitation responded differently to the different phases of the microstructure. The austenite phase was observed to have more homogeneous and smoother layer of HAP. In addition, the growth of HAP was sometimes favored on the austenite phase rather than on ferrite phase. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Surface modification of commercial tin coatings by carbon ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L J; Sood, D K; Manory, R R [Royal Melbourne Inst. of Tech., VIC (Australia)

    1994-12-31

    Commercial TiN coatings of about 2 {mu}m thickness on high speed steel substrates were implanted at room temperature with 95 keV carbon ions at nominal doses between 1 x 10{sup 17} - 8x10{sup 17} ions cm{sup -2}. Carbon ion implantation induced a significant improvement in ultramicrohardness, friction coefficient and wear properties. The surface microhardness increases monotonically by up to 115% until a critical dose is reached. Beyond this dose the hardness decreases, but remains higher than that of unimplanted sample. A lower friction coefficient and a longer transition period towards a steady state condition were obtained by carbon ion implantation. The changes in tribomechanical properties are discussed in terms of radiation damage and possible formation of a second phase rich in carbon. 6 refs., 3 figs.

  18. Surface modification of commercial tin coatings by carbon ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L.J.; Sood, D.K.; Manory, R.R. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Commercial TiN coatings of about 2 {mu}m thickness on high speed steel substrates were implanted at room temperature with 95 keV carbon ions at nominal doses between 1 x 10{sup 17} - 8x10{sup 17} ions cm{sup -2}. Carbon ion implantation induced a significant improvement in ultramicrohardness, friction coefficient and wear properties. The surface microhardness increases monotonically by up to 115% until a critical dose is reached. Beyond this dose the hardness decreases, but remains higher than that of unimplanted sample. A lower friction coefficient and a longer transition period towards a steady state condition were obtained by carbon ion implantation. The changes in tribomechanical properties are discussed in terms of radiation damage and possible formation of a second phase rich in carbon. 6 refs., 3 figs.

  19. Surface modification of commercial tin coatings by carbon ion implantation

    International Nuclear Information System (INIS)

    Liu, L.J.; Sood, D.K.; Manory, R.R.

    1993-01-01

    Commercial TiN coatings of about 2 μm thickness on high speed steel substrates were implanted at room temperature with 95 keV carbon ions at nominal doses between 1 x 10 17 - 8x10 17 ions cm -2 . Carbon ion implantation induced a significant improvement in ultramicrohardness, friction coefficient and wear properties. The surface microhardness increases monotonically by up to 115% until a critical dose is reached. Beyond this dose the hardness decreases, but remains higher than that of unimplanted sample. A lower friction coefficient and a longer transition period towards a steady state condition were obtained by carbon ion implantation. The changes in tribomechanical properties are discussed in terms of radiation damage and possible formation of a second phase rich in carbon. 6 refs., 3 figs

  20. Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

    Science.gov (United States)

    Niiya, Hirofumi; Nishimura, Kouichi

    2017-05-01

    We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from 10-5 to 10 m above the flat surface. The numerical results are as follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below 10 cm and gradual wind response above 10 cm. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below 100 µm remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above 300 µm is less than the wind speed, whereas that below 300 µm exceeds the wind speed because of descending particles. (v) The particle diameter increases with height in the saltation layer, and the relationship is expressed as a power function. Through comparisons with the previously reported random-flight model, we find a crucial problem that empirical splash functions cannot reproduce particle dynamics at a relatively high wind speed.

  1. Synthesis and surface properties of submicron barium sulfate particles

    International Nuclear Information System (INIS)

    Zhang Ming; Zhang Bao; Li Xinhai; Yin Zhoulan; Guo Xueyi

    2011-01-01

    Barium sulfate particles were synthesized in the presence of EDTA at room temperature. X-ray diffractometry (XRD), Fourier transform infrared resonance (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of BaSO 4 particles. The effect of the preparation parameters on the particle size distribution and morphology was investigated. The conditional formation constants of Ba-EDTA at different pH values were calculated. The results show that the size and morphology of BaSO 4 particles can be effectively controlled by adding EDTA in the precipitation process. Among all the operation conditions, the pH value has significant effect on the particle size. The obtained barium sulfate particles are spherical and well dispersed at pH = 9-10. Zeta potentials of BaSO 4 were measured at different pH. The isoelectric point (IEP) of barium sulfate colloid appears at pH 6.92. The model of the solid-solution interface at a particle of BaSO 4 was presented. The FTIR result indicates that the surface of the prepared BaSO 4 absorbs the functional groups of EDTA, which lower the IEP of the barium sulfate particles.

  2. Synthesis and surface properties of submicron barium sulfate particles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ming, E-mail: csu.light@yahoo.com.cn [College of Chemistry and Chemical Engineering, Zhaoqing University, Zhaoqing 526061 (China); School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhang Bao; Li Xinhai [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Yin Zhoulan [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Guo Xueyi [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China)

    2011-10-15

    Barium sulfate particles were synthesized in the presence of EDTA at room temperature. X-ray diffractometry (XRD), Fourier transform infrared resonance (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of BaSO{sub 4} particles. The effect of the preparation parameters on the particle size distribution and morphology was investigated. The conditional formation constants of Ba-EDTA at different pH values were calculated. The results show that the size and morphology of BaSO{sub 4} particles can be effectively controlled by adding EDTA in the precipitation process. Among all the operation conditions, the pH value has significant effect on the particle size. The obtained barium sulfate particles are spherical and well dispersed at pH = 9-10. Zeta potentials of BaSO{sub 4} were measured at different pH. The isoelectric point (IEP) of barium sulfate colloid appears at pH 6.92. The model of the solid-solution interface at a particle of BaSO{sub 4} was presented. The FTIR result indicates that the surface of the prepared BaSO{sub 4} absorbs the functional groups of EDTA, which lower the IEP of the barium sulfate particles.

  3. Photon emission produced by particle-surface collisions

    International Nuclear Information System (INIS)

    White, C.W.; Tolk, N.H.

    1976-02-01

    Visible, ultraviolet, and infrared optical emission results from low-energy (20 eV-10 keV) particle-surface collisions. Several distinct kinds of collision induced optical radiation are discussed which provide fundamental information on particle-solid collision processes. Line radiation arises from excited states of sputtered surface constituents and backscattered beam particles. This radiation uniquely identifies the quantum state of sputtered or reflected particles, provides a method for identifying neutral atoms sputtered from the surface, and serves as the basis for a sensitive surface analysis technique. Broadband radiation from the bulk of the solid is attributed to the transfer of projectile energy to the electrons in the solid. Continuum emission observed well in front of transition metal targets is believed to arise from excited atom clusters (diatomic, triatomic, etc.) ejected from the solid in the sputtering process. Application of sputtered atom optical radiation for surface and depth profile analysis is demonstrated for the case of submonolayer quantities of chromium on silicon and aluminum implanted in SiO 2

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

    Directory of Open Access Journals (Sweden)

    Eduardo Robles

    2018-04-01

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

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

    Science.gov (United States)

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

    2018-05-01

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

  6. Particle dry deposition to water surfaces: Processes and consequences

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.

    2000-01-01

    flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...... of the physical and chemical processes which dictate the quantity (and direction) of atmosphere-surface fluxes of trace chemicals to (and above) water surfaces with particular emphasis on the role of particles. Dry deposition (transfer to the surface in the absence of precipitation) of particles is determined...... efforts to simulate and measure fluxes close to the coastline. These arise in part from the complexity of atmospheric flow in this region where energy and chemical fluxes are highly inhomogeneous in space and time and thermally generated atmospheric circulations are commonplace. (C) 2000 Elsevier Science...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-15

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

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

    International Nuclear Information System (INIS)

    Yuan Hua; Wang Chengguo; Zhang Shan; Lin Xue

    2012-01-01

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

  9. Particle separation by phase modulated surface acoustic waves.

    Science.gov (United States)

    Simon, Gergely; Andrade, Marco A B; Reboud, Julien; Marques-Hueso, Jose; Desmulliez, Marc P Y; Cooper, Jonathan M; Riehle, Mathis O; Bernassau, Anne L

    2017-09-01

    High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

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

    2004-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  15. Photometric imaging in particle size measurement and surface visualization.

    Science.gov (United States)

    Sandler, Niklas

    2011-09-30

    The aim of this paper is to give an insight into photometric particle sizing approaches, which differ from the typical particle size measurement of dispersed particles. These approaches can often be advantageous especially for samples that are moist or cohesive, when dispersion of particles is difficult or sometimes impossible. The main focus of this paper is in the use of photometric stereo imaging. The technique allows the reconstruction of three-dimensional images of objects using multiple light sources in illumination. The use of photometric techniques is demonstrated in at-line measurement of granules and on-line measurement during granulation and dry milling. Also, surface visualization and roughness measurements are briefly discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Tracheobronchial and Alveolar Particle Surface Area Doses in Smokers

    Directory of Open Access Journals (Sweden)

    Fernanda Carmen Fuoco

    2017-01-01

    Full Text Available Cigarette smoke is the main cause of lung cancer events. Mainstream cigarette smoke (MSS is a direct concern for smokers, but also the secondhand smoke (SHS contributes to the smoker exposure. In addition, smoker exposure is affected by the “free-smoke” particle exposure (B, related to the micro-environments where smokers spend time. The aim of this paper is to evaluate the daily alveolar and tracheobronchial deposited fractions of airborne particles for smokers as the sum of these three contributions: MSS, SHS, and B. Measurements of particle surface area distributions in the MSS were performed through a Scanning Mobility Particle Sizer, an Aerodynamic Particle Sizer, and a Thermo-dilution system on five types of conventional cigarettes. A Monte Carlo method was then applied to evaluate the most probable value of dose received during the inhalation of MSS by smokers. Measurements of particle concentrations in SHS and at the “free-smoke” particle background (B were performed through 24-h monitoring at a personal scale of adult smoker through hand-held devices. This paper found that the total daily deposited dose for typical smokers was 1.03 × 105 mm2·day−1. The main contribution of such a huge daily dose was addressable to the MSS (98% while SHS contributed 1.1%, increasing up to 2% for people smoking only while traveling in a car.

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

    Directory of Open Access Journals (Sweden)

    Norhan Nady

    2016-04-01

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

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

    International Nuclear Information System (INIS)

    Zhang Lei; Zhong Min; Ge Hongliang

    2011-01-01

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

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

    Science.gov (United States)

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

    2015-08-07

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    Science.gov (United States)

    Cao, Jiliang; Wang, Chaoxia

    2017-05-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

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

    International Nuclear Information System (INIS)

    Iswani Gitawati; Rany Saptaaji

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-30

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

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

    NARCIS (Netherlands)

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

    2008-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

    2010-01-01

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

  12. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.F. [Xi' an High-technology Institute, Xi' an 710025 (China)], E-mail: xiaofang_liu@263.net; Wu, Q.Y.; Wang, H.G. [Xi' an High-technology Institute, Xi' an 710025 (China)

    2008-06-15

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion.

  13. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    International Nuclear Information System (INIS)

    Liu, X.F.; Wu, Q.Y.; Wang, H.G.

    2008-01-01

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  17. The modification of hybrid method of ant colony optimization, particle swarm optimization and 3-OPT algorithm in traveling salesman problem

    Science.gov (United States)

    Hertono, G. F.; Ubadah; Handari, B. D.

    2018-03-01

    The traveling salesman problem (TSP) is a famous problem in finding the shortest tour to visit every vertex exactly once, except the first vertex, given a set of vertices. This paper discusses three modification methods to solve TSP by combining Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO) and 3-Opt Algorithm. The ACO is used to find the solution of TSP, in which the PSO is implemented to find the best value of parameters α and β that are used in ACO.In order to reduce the total of tour length from the feasible solution obtained by ACO, then the 3-Opt will be used. In the first modification, the 3-Opt is used to reduce the total tour length from the feasible solutions obtained at each iteration, meanwhile, as the second modification, 3-Opt is used to reduce the total tour length from the entire solution obtained at every iteration. In the third modification, 3-Opt is used to reduce the total tour length from different solutions obtained at each iteration. Results are tested using 6 benchmark problems taken from TSPLIB by calculating the relative error to the best known solution as well as the running time. Among those modifications, only the second and third modification give satisfactory results except the second one needs more execution time compare to the third modifications.

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

    International Nuclear Information System (INIS)

    Gao Yukui

    2011-01-01

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

  19. Modification of the surface properties of a polyimide film during irradiation with polychromic light

    International Nuclear Information System (INIS)

    Rosu, Liliana; Sava, Ion; Rosu, Dan

    2011-01-01

    The behaviour of a polyimide film with the aromatic structure during the exposure to UV light with λ > 290 nm was studied. Significant changes in color surface and gloss surface were identified during irradiation. Sample became lighten and less glossy after exposure to the light. These modifications were correlated with the structural changes in FTIR spectra. Based on changes in FTIR spectra recorded during irradiation, a mechanism for the photochemical degradation of polyimide film was proposed.

  20. Reversible electrochemical modification of the surface of a semiconductor by an atomic-force microscope probe

    Energy Technology Data Exchange (ETDEWEB)

    Kozhukhov, A. S., E-mail: antonkozhukhov@yandex.ru; Sheglov, D. V.; Latyshev, A. V. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    2017-04-15

    A technique for reversible surface modification with an atomic-force-microscope (AFM) probe is suggested. In this method, no significant mechanical or topographic changes occur upon a local variation in the surface potential of a sample under the AFM probe. The method allows a controlled relative change in the ohmic resistance of a channel in a Hall bridge within the range 20–25%.

  1. Modification of chitosan membranes with nanosilica particles as polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kusumastuti, Ella, E-mail: ella.kusuma@gmail.com; Siniwi, Widasari Trisna, E-mail: wsiniwi@gmail.com; Mahatmanti, F. Widhi; Jumaeri [Department of Chemistry, Faculty of Mathematics and Natural Sciences, State University of Semarang D6 Building 2" n" d floor, Sekaran Unnes Campus, Gunungpati, Semarang (Indonesia); Atmaja, Lukman; Widiastuti, Nurul [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Tenth November Institute of Technology Keputih ITS Campus, Sukolilo, Surabaya (Indonesia)

    2016-04-19

    Chitosan has been widely used as polymer matrix for Polymer Electrolyte Membrane (PEM) application replacing Nafion which has shortcomings in terms of high methanol permeability that degrades the performance of fuel cells. Chitosan membranes modification is performed by adding nanosilica to prevent methanol transport through the membrane. Nanosilica is synthesized by sol-gel method and the particle diameter is obtained by analysis using Breunner Emmet Teller (BET) that is 6.59 nm. Nanosilica is mixed with chitosan solution to obtain nanosilica-chitosan as polymer electrolyte membrane. The membranes are synthesized through phase inversion method with nanosilica composition including 0; 0.5; 1; 2; 3; 5; and 10% w/w of chitosan. Characterization of the membranes indicate that the results of water swelling, proton conductivity and methanol permeability of the membrane with 3% nanosilica respectively were 49.23%, 0.231 S/cm, and 5.43 x 10{sup −7} cm{sup 2}/s. Based on the results of membrane selectivity calculation, the optimum membrane is the composition of 3% nanosilica with value 5.91 x 105 S s cm{sup −3}. The results of functional groups analysis with FTIR showed that it was only physical interaction that occurred between chitosan and nanosilica since no significant changes found in peak around the wave number 1000-1250 cm{sup −-1}.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-30

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-03-15

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  7. Modeled heating and surface erosion comparing motile (gas borne) and stationary (surface coating) inert particle additives

    International Nuclear Information System (INIS)

    Buckingham, A.C.; Siekhaus, W.J.

    1982-01-01

    The unsteady, non-similar, chemically reactive, turbulent boundary layer equations are modified for gas plus dispersed solid particle mixtures, for gas phase turbulent combustion reactions and for heterogeneous gas-solid surface erosive reactions. The exterior (ballistic core) edge boundary conditions for the solutions are modified to include dispersed particle influences on core propellant combustion-generated turbulence levels, combustion reactants and products, and reaction-induced, non-isentropic mixture states. The wall surface (in this study it is always steel) is considered either bare or coated with a fixed particle coating which is conceptually non-reactive, insulative, and non-ablative. Two families of solutions are compared. These correspond to: (1) consideration of gas-borne, free-slip, almost spontaneously mobile (motile) solid particle additives which influence the turbulent heat transfer at the uncoated steel surface and, in contrast, (2) consideration of particle-free, gas phase turbulent heat transfer to the insulated surface coated by stationary particles. Significant differences in erosive heat transfer are found in comparing the two families of solutions over a substantial range of interior ballistic flow conditions. The most effective influences on reducing erosive heat transfer appear to favor mobile, gas-borne particle additives

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Science.gov (United States)

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

    2017-09-01

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

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

    KAUST Repository

    Jahangir, Daniyal

    2017-12-01

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

  12. Surface modification of silica nanoparticles by UV-induced graft polymerization of methyl methacrylate.

    Science.gov (United States)

    Kim, Sooyeon; Kim, Eunhye; Kim, Sungsoo; Kim, Woosik

    2005-12-01

    In this study we modified the surface of silica nanoparticles with methyl methacrylate by UV-induced graft polymerization. It is a surface-initiated polymerization reaction induced by ultraviolet irradiation. The resulting organic-inorganic nanocomposites were near-monodisperse and fabricated without homopolymerization of the monomer. Substantial increase in mean particle size was observed by SEM image analysis after UV-induced grafting of methyl methacrylate onto pure silica particles. FT-Raman spectroscopy and X-ray photoelectron spectroscopy studies of these materials revealed the successful grafting of methyl methacrylate onto the silica surface. The formation of a covalent bond between the grafted PMMA chains and silica surface was indicated by FT-Raman spectra. Thermogravimetric analysis of the PMMA-grafted silica particles indicated the polymer contents in good agreement with SEM photographs.

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    International Nuclear Information System (INIS)

    Abel, B.; Aslan, K.

    2012-01-01

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

  15. Surface monofunctionalized polymethyl pentene hollow fiber membranes by plasma treatment and hemocompatibility modification for membrane oxygenators

    Science.gov (United States)

    Huang, Xin; Wang, Weiping; Zheng, Zhi; Fan, Wenling; Mao, Chun; Shi, Jialiang; Li, Lei

    2016-01-01

    The hemocompatibility of polymethyl pentene (PMP) hollow fiber membranes (HFMs) was improved through surface modification for membrane oxygenator applications. The modification was performed stepwise with the following: (1) oxygen plasma treatment, (2) functionalization of monosort hydroxyl groups through NaBH4 reduction, and (3) grafting 2-methacryloyloxyethyl phosphorylcholine (MPC) or heparin. SEM, ATR-FTIR, and XPS analyses were conducted to confirm successful grafting during the modification. The hemocompatibility of PMP HFMs was analyzed and compared through protein adsorption, platelet adhesion, and coagulation tests. Pure CO2 and O2 permeation rates, as well as in vitro gas exchange rates, were determined to evaluate the mass transfer properties of PMP HFMs. SEM results showed that different nanofibril topographies were introduced on the HFM surface. ATR-FTIR and XPS spectra indicated the presence of functionalization of monosort hydroxyl group and the grafting of MPC and heparin. Hemocompatibility evaluation results showed that the modified PMP HFMs presented optimal hemocompatibility compared with pristine HFMs. Gas permeation results revealed that gas permeation flux increased in the modified HFMs because of dense surface etching during the plasma treatment. The results of in vitro gas exchange rates showed that all modified PMP HFMs presented decreased gas exchange rates because of potential surface fluid wetting. The proposed strategy exhibits a potential for fabricating membrane oxygenators for biomedical applications to prevent coagulation formation and alter plasma-induced surface topology and composition.

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

    International Nuclear Information System (INIS)

    Wang Chen; Chen Jierong; Li Ru

    2008-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

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

  19. Modelling free surface flows with smoothed particle hydrodynamics

    Directory of Open Access Journals (Sweden)

    L.Di G.Sigalotti

    2006-01-01

    Full Text Available In this paper the method of Smoothed Particle Hydrodynamics (SPH is extended to include an adaptive density kernel estimation (ADKE procedure. It is shown that for a van der Waals (vdW fluid, this method can be used to deal with free-surface phenomena without difficulties. In particular, arbitrary moving boundaries can be easily handled because surface tension is effectively simulated by the cohesive pressure forces. Moreover, the ADKE method is seen to increase both the accuracy and stability of SPH since it allows the width of the kernel interpolant to vary locally in a way that only the minimum necessary smoothing is applied at and near free surfaces and sharp fluid-fluid interfaces. The method is robust and easy to implement. Examples of its resolving power are given for both the formation of a circular liquid drop under surface tension and the nonlinear oscillation of excited drops.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-01

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

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

    International Nuclear Information System (INIS)

    Xu Bing; Wang Xiaoshu; Lu Yun

    2006-01-01

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  3. The effect of surface-bulk potential difference on the kinetics of intercalation in core-shell active cathode particles

    Science.gov (United States)

    Kazemiabnavi, Saeed; Malik, Rahul; Orvananos, Bernardo; Abdellahi, Aziz; Ceder, Gerbrand; Thornton, Katsuyo

    2018-04-01

    Surface modification of active cathode particles is commonly observed in battery research as either a surface phase evolving during the cycling process, or intentionally engineered to improve capacity retention, rate capability, and/or thermal stability of the cathode material. Here, a continuum-scale model is developed to simulate the galvanostatic charge/discharge of a cathode particle with core-shell heterostructure. The particle is assumed to be comprised of a core material encapsulated by a thin layer of a second phase that has a different open-circuit voltage. The effect of the potential difference between the surface and bulk phases (Ω) on the kinetics of lithium intercalation and the galvanostatic charge/discharge profiles is studied at different values of Ω, C-rates, and exchange current densities. The difference between the Li chemical potential in the surface and bulk phases of the cathode particle results in a concentration difference between these two phases. This leads to a charge/discharge asymmetry in the galvanostatic voltage profiles, causing a decrease in the accessible capacity of the particle. These effects are more significant at higher magnitudes of surface-bulk potential difference. The proposed model provides detailed insight into the kinetics and voltage behavior of the intercalation/de-intercalation processes in core-shell heterostructure cathode particles.

  4. Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

    International Nuclear Information System (INIS)

    Kumar, Vijay; Ali, Yasir; Sharma, Kashma; Kumar, Vinod; Sonkawade, R.G.; Dhaliwal, A.S.; Swart, H.C.

    2014-01-01

    Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li 3+ ion beam irradiation for various fluences (1 × 10 11 , 1 × 10 12 and 1 × 10 13 ions/cm 2 ). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence

  5. Swift heavy ions induced surface modifications in Ag-polypyrrole composite films synthesized by an electrochemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Vijay, E-mail: vijays_phy@rediffmail.com [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Ali, Yasir [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Sharma, Kashma [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Department of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan 173212 (India); Kumar, Vinod [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa); Sonkawade, R.G. [Inter University Accelerator Center, Aruna Asif Ali Marg, New Delhi 110067 (India); Dhaliwal, A.S. [Department of Physics, Sant Longowal Institute of Engineering and Technology, Longowal, District Sangrur 148106, Punjab (India); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300 (South Africa)

    2014-03-15

    Highlights: • Two steps electrochemical synthesis for the fabrication of Ag-polypyrrole composite films. • Surface modifications by swift heavy ion beam. • SEM image shows the formation of craters and humps after irradiation. • Detailed structural analysis by Raman spectroscopy. - Abstract: The general aim of this work was to study the effects of swift heavy ions on the properties of electrochemically synthesized Ag-polypyrrole composite thin films. Initially, polypyrrole (PPy) films were electrochemically synthesized on indium tin oxide coated glass surfaces using a chronopotentiometery technique, at optimized process conditions. The prepared PPy films have functioned as working electrodes for the decoration of submicron Ag particles on the surface of the PPy films through a cyclicvoltammetry technique. Towards probing the effect of swift heavy ion irradiation on the structural and morphological properties, the composite films were subjected to a 40 MeV Li{sup 3+} ion beam irradiation for various fluences (1 × 10{sup 11}, 1 × 10{sup 12} and 1 × 10{sup 13} ions/cm{sup 2}). Comparative microstructural investigations were carried out after the different ion fluences using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy and micro-Raman spectroscopy techniques. Raman and SEM studies revealed that the structure of the films became disordered after irradiation. The SEM studies of irradiated composite films show significant changes in their surface morphologies. The surface was smoother at lower fluence but craters were observed at higher fluence.

  6. The magnetic field application for the gas discharge plasma control in processes of surface coating and modification

    International Nuclear Information System (INIS)

    Asadullin, T Ya; Galeev, I G

    2017-01-01

    In this paper the method of magnetic field application to control the gas discharge plasma effect on the various surfaces in processes of surface coating and modification is considered. The magnetic field directed perpendicular to the direction of electric current in the gas discharge plasma channel is capable to reject this plasma channel due to action of Lorentz force on the moving electrically charged particles [1,2]. The three-dimensional spatial structure of magnetic field is created by system of necessary quantity of the magnets located perpendicular to the direction of course of electric current in the gas-discharge plasma channel. The formation of necessary spatial distribution of magnetic field makes possible to obtain a required distribution of plasma parameters near the processed surfaces. This way of the plasma channel parameters spatial distribution management is the most suitable for application in processes of plasma impact on a surface of irregular shape and in cases when the selective impact of plasma on a part of a surface of a product is required. It is necessary to apply automated computer management of the process parameters [3] to the most effective plasma impact. (paper)

  7. Enhancing adhesion of yeast brewery strains to chamotte carriers through aminosilane surface modification.

    Science.gov (United States)

    Berlowska, Joanna; Kregiel, Dorota; Ambroziak, Wojciech

    2013-07-01

    The adhesion of cells to solid supports is described as surface-dependent, being largely determined by the properties of the surface. In this study, ceramic surfaces modified using different organosilanes were tested for proadhesive properties using industrial brewery yeast strains in different physiological states. Eight brewing strains were tested: bottom-fermenting Saccharomyces pastorianus and top-fermenting Saccharomyces cerevisiae. To determine adhesion efficiency light microscopy, scanning electron microscopy and the fluorymetric method were used. Modification of chamotte carriers by 3-(3-anino-2-hydroxy-1-propoxy) propyldimethoxysilane and 3-(N, N-dimethyl-N-2-hydroxyethyl) ammonium propyldimethoxysilane groups increased their biomass load significantly.

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

    Directory of Open Access Journals (Sweden)

    Alessandra Piscitelli

    2017-06-01

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

  9. Nanocapillary Atmospheric Pressure Plasma Jet: A Tool for Ultrafine Maskless Surface Modification at Atmospheric Pressure.

    Science.gov (United States)

    Motrescu, Iuliana; Nagatsu, Masaaki

    2016-05-18

    With respect to microsized surface functionalization techniques we proposed the use of a maskless, versatile, simple tool, represented by a nano- or microcapillary atmospheric pressure plasma jet for producing microsized controlled etching, chemical vapor deposition, and chemical modification patterns on polymeric surfaces. In this work we show the possibility of size-controlled surface amination, and we discuss it as a function of different processing parameters. Moreover, we prove the successful connection of labeled sugar chains on the functionalized microscale patterns, indicating the possibility to use ultrafine capillary atmospheric pressure plasma jets as versatile tools for biosensing, tissue engineering, and related biomedical applications.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

    Tamura, Ryo; Uemoto, Shinji; Tabata, Yasuhiko

    2017-07-15

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  16. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-11-03

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

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

    Science.gov (United States)

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

    2010-11-01

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

  18. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-01-01

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

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

    Science.gov (United States)

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

    2018-06-01

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

  20. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    Directory of Open Access Journals (Sweden)

    Himansu Sekhar Nanda

    2016-11-01

    Full Text Available The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium-doped cerium oxide nanoparticles (SmCNPs as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy-ethoxy]-ethoxy}-hexyl triethoxysilane (MEEETES were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

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

    KAUST Repository

    Matin, Asif

    2014-06-01

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

  2. SURFACE MODIFICATION OF SEMICONDUCTOR THIN FILM OF TiO2 ON GRAPHITE SUBSTRATE BY Cu-ELECTRODEPOSITION

    Directory of Open Access Journals (Sweden)

    Fitria Rahmawati

    2010-06-01

    Full Text Available Surface modification of graphite/TiO2 has been done by mean of Cu electrodeposition. This research aims to study the effect of Cu electrodeposition on photocatalytic enhancing of TiO2. Electrodeposition has been done using CuSO4 0,4 M as the electrolyte at controlled current. The XRD pattern of modified TiO2 thin film on graphite substrate exhibited new peaks at 2θ= 43-44o and 2θ= 50-51o that have been identified as Cu with crystal cubic system, face-centered crystal lattice and crystallite size of 26-30 nm. CTABr still remains in the material as impurities. Meanwhile, based on morphological analysis, Cu particles are dissipated in the pore of thin film. Graphite/TiO2/Cu has higher photoconversion efficiency than graphite/TiO2.   Keywords: semiconductor, graphite/TiO2, Cu electrodeposition

  3. Modification of titanium surfaces by adding antibiotic-loaded PHB spheres and PEG for biomedical applications.

    Science.gov (United States)

    Rodríguez-Contreras, Alejandra; Marqués-Calvo, María Soledad; Gil, Francisco Javier; Manero, José María

    2016-08-01

    Novel researches are focused on the prevention and management of post-operative infections. To avoid this common complication of implant surgery, it is preferable to use new biomaterials with antibacterial properties. Therefore, the aim of this work is to develop a method of combining the antibacterial properties of antibiotic-loaded poly(3-hydroxybutyrate) (PHB) nano- and micro-spheres and poly(ethylene glycol) (PEG) as an antifouling agent, with titanium (Ti), as the base material for implants, in order to obtain surfaces with antibacterial activity. The Ti surfaces were linked to both PHB particles and PEG by a covalent bond. This attachment was carried out by firstly activating the surfaces with either Oxygen plasma or Sodium hydroxide. Further functionalization of the activated surfaces with different alkoxysilanes allows the reaction with PHB particles and PEG. The study confirms that the Ti surfaces achieved the antibacterial properties by combining the antibiotic-loaded PHB spheres, and PEG as an antifouling agent.

  4. Surface modification of chitin using ultrasound-assisted and supercritical CO{sub 2} technologies for cobalt adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dotto, Guilherme L., E-mail: guilherme_dotto@yahoo.com.br; Cunha, Jeanine M., E-mail: jeaninecunha@gmail.com; Calgaro, Camila O., E-mail: camila.itepjr@gmail.com; Tanabe, Eduardo H., E-mail: edutanabe@yahoo.com.br; Bertuol, Daniel A., E-mail: dbertuol@gmail.com

    2015-09-15

    Highlights: • Chitin was modified by ultrasound-assisted (UA) and supercritical (SCO{sub 2}) technologies. • Chitin, UA-chitin and SCO{sub 2}-chitin were used as adsorbents for Co(II). • UA and SCO{sub 2} treatments provided increase of 20 and 3 times in chitin surface area. • The Co(II) adsorption capacity increased until 67.8%, using UA-chitin. - Abstract: Ultrasound-assisted (UA) and supercritical CO{sub 2} technologies (SCO{sub 2}) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N{sub 2} adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions. The adsorption study was performed by equilibrium isotherms and kinetic curves. The chitin particle characteristics, such as, surface area, pore volume and porosity were improved by the UA and SCO{sub 2} treatments. The crystallinity index decreased after the UA and SCO{sub 2} treatments, and also, intense surface modifications were observed. Langmuir and Freundlich models were adequate to represent the adsorption equilibrium. The maximum adsorption capacities were 50.03, 83.94 and 63.08 mg g{sup −1} for unmodified chitin, UA surface modified chitin and SCO{sub 2} surface modified chitin. The adsorption kinetic curves were well represented by the pseudo-second order model. UA and SCO{sub 2} technologies are alternatives to modify the chitin surface and improve its adsorption characteristics.

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

    Science.gov (United States)

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

    2014-01-08

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

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

    CERN Document Server

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

    2002-01-01

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

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

    CERN Document Server

    Zhang, Guigen

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Kevkić Tijana

    2016-01-01

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

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

    DEFF Research Database (Denmark)

    Lackner, Susanne; Holmberg, Maria; Terada, Akihiko

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Guan Weishu; Wen Yunjian; Fang Yan; Yin Yongxiang

    1996-02-01

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

  11. Reactivity of surface of metal oxide particles: from adsorption of ions to deposition of colloidal particles

    International Nuclear Information System (INIS)

    Lefevre, Gregory

    2010-01-01

    In this Accreditation to supervise research (HDR), the author proposes an overview of his research works in the field of chemistry. These works more particularly addressed the understanding of the surface reactivity of metal oxide particles and its implication on sorption and adherence processes. In a first part, he addresses the study of surface acidity-alkalinity: measurement of surface reactivity by acid-base titration, stability of metal oxides in suspension, effect of morphology on oxide-hydroxide reactivity. The second part addresses the study of sorption: reactivity of iron oxides with selenium species, sorption of sulphate ions on magnetite, attenuated total reflection infrared spectroscopy (ATR-IR). Adherence effects are addressed in the third part: development of an experimental device to study adherence in massive substrates, deposition of particles under turbulent flow. The last part presents a research project on the effect of temperature on ion sorption at solids/solutions interfaces, and on the adherence of metal oxide particles. The author gives his detailed curriculum, and indicates his various publications, teaching activities, research and administrative responsibilities

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-30

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2005-11-01

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  16. Surface modification of coconut shell based activated carbon for the improvement of hydrophobic VOC removal.

    Science.gov (United States)

    Li, Lin; Liu, Suqin; Liu, Junxin

    2011-08-30

    In this study, coconut shell based carbons were chemically treated by ammonia, sodium hydroxide, nitric acid, sulphuric acid, and phosphoric acid to determine suitable modification for improving adsorption ability of hydrophobic volatile organic compounds (VOCs) on granular activated carbons (GAC). The saturated adsorption capacities of o-xylene, a hydrophobic volatile organic compound, were measured and adsorption effects of the original and modified activated carbons were compared. Results showed that GAC modified by alkalis had better o-xylene adsorption capacity. Uptake amount was enhanced by 26.5% and reduced by 21.6% after modification by NH(3)H(2)O and H(2)SO(4), respectively. Compared with the original, GAC modified by acid had less adsorption capacity. Both SEM/EDAX and BET were used to identify the structural characteristics of the tested GAC, while IR spectroscopy and Boehm's titration were applied to analysis the surface functional groups. Relationships between physicochemical characteristics of GAC and their adsorption performances demonstrated that o-xylene adsorption capacity was related