Showing papers on "Surface modification published in 1999"
TL;DR: In this paper, an alkaline treatment was used to enhance both the matrix fiber wetting and the chemical surface modification in order to improve the physicochemical interactions at the fiber-matrix interphase.
Abstract: The interfacial shear strength (IFSS) between natural fibers and a thermoplastic matrix has been improved by the morphological and silane chemical modification of the fiber surface. An alkaline treatment was used to enhance both the matrix fiber wetting and the chemical surface modification in order to improve the physicochemical interactions at the fiber–matrix interphase. For characterization of the mechanical properties of such interphase, a modification of the micromechanical techniques commonly used in the characterization of the IFSS for circular-cross-section smooth fibers is proposed. The relationships developed for circular fibers were modified to incorporate the natural fiber perimeter instead of an equivalent fiber diameter. From the micromechanical test's results it was found that both surface modifications, preimpregnation and chemical, improves the fiber–matrix IFSS. Finally, the results obtained from the single fiber fragmentation test seem to better agree with the effective mechanical properties measured for the laminated material than those obtained with the pull out test.
735 citations
TL;DR: The current technology available for surface microfabrication with macromolecules to regulate cell functions is reviewed and surface topology, and surface modification with hydrophilic or hydrophobic polymers, electrically charged polymers.
510 citations
Patent•
15 Jan 1999
TL;DR: In this paper, a method of obtaining a porous titanium surface suitable for medical implants is provided, where the titanium surface is exposed to a plasma comprising a reactive plasma gas, the reactive surface gas comprising an active etching species and a sputtering gas.
Abstract: A method of obtaining a porous titanium surface suitable for medical implants is provided. The titanium surface is exposed to a plasma comprising a reactive plasma gas, the reactive plasma gas comprising an active etching species and a sputtering gas. The plasma conditions are effective to modify the titanium surface and provide surface porosity. The plasma conditions are effective to non-uniformly etch and sputter the titanium surface.
452 citations
TL;DR: In this article, the interaction between the anhydride groups of maleated polypropylene (MAPP) and hydroxyl groups of wood fiber, and the mechanisms responsible for the interfacial adhesion between wood fiber and poly-propylene matrix were investigated.
Abstract: The interfacial adhesion between wood fiber and thermoplastic matrix polymer plays an important role in determining the performance of wood-polymer composites. The objectives of this research were to elucidate the interaction between the anhydride groups of maleated polypropylene (MAPP) and hydroxyl groups of wood fiber, and to clarify the mechanisms responsible for the interfacial adhesion between wood fiber and polypropylene matrix. The modification techniques used were bulk treatment in a thermokinetic reactive processor and solution coating in xylene. FT-IR was used to identify the nature of bonds between wood fiber and MAPP. IGC and wood veneer pull-out test was used to estimate the interfacial adhesion. Mechanical properties of injection molded woodfiber-polypropylene composites were also determined and compared with the results of esterification reaction and interfacial adhesion tests. Confocal Microscopy was employed to observe the morphology at the wood fiber-polypropylene interface, and the dispersion and orientation of wood fiber in the polypropylene matrix, respectively. The effectiveness of MAPP to improve the mechanical properties (particularly the tensile strength) of the composites was attributed to the compatibilization effect which is accomplished by reducing the total wood fiber surface free energy, improving the polymer matrix impregnation, improving fiber dispersion, improving fiber orientation, and enhancing the interfacial adhesion through mechanical interlocking. There was no conclusive evidence of the effects of ester links on the mechanical properties of the composites.
375 citations
TL;DR: A multistep surface modification procedure for the creation of DNA arrays on chemically modified gold surfaces that can be used in surface plasmon resonance (SPR) imaging studies of protein−DNA interactions is demonstrated in this article.
Abstract: A multistep surface modification procedure for the creation of DNA arrays on chemically modified gold surfaces that can be used in surface plasmon resonance (SPR) imaging studies of protein−DNA interactions is demonstrated. The multistep procedure is required to create an array of spots that are surrounded first by a hydrophobic background which allows for the pinning of aqueous DNA solutions onto individual array elements and then to replace that hydrophobic background with one that resists the nonspecific adsorption of proteins during in situ SPR imaging measurements. An amine-terminated alkanethiol monolayer is employed as the base layer, and Fmoc and PEG modifiers are used to create the sequentially hydrophobic and protein adsorption-resistant surfaces, respectively. Specifically, the chemical modification steps are the following: (1) the adsorption and self-assembly of an 11-mercaptoundecylamine (MUAM) monolayer on an evaporated gold thin film, (2) the reaction of the MUAM monolayer with an Fmoc pro...
359 citations
TL;DR: The past decades and current R&D of biomaterials and medical implants show some general trends, including an increased degree of functionalization of the material surface, better to meet the demands of the biological host system.
Abstract: The past decades and current R&D of biomaterials and medical implants show some general trends. One major trend is an increased degree of functionalization of the material surface, better to meet the demands of the biological host system. While the biomaterials of the past and those in current use are essentially bulk materials (metals, ceramics, polymers) or special compounds (bioglasses), possibly with some additional coating (e.g., hydroxyapatite), the current R&D on surface modifications points toward much more complex and multifunctional surfaces for the future. Such surface modifications can be divided into three classes, one aiming toward an optimized three-dimensional physical microarchitecture of the surface (pore size distributions, "roughness", etc.), the second one focusing on the (bio) chemical properties of surface coatings and impregnations (ion release, multi-layer coatings, coatings with biomolecules, controlled drug release, etc.), and the third one dealing with the viscoelastic properties (or more generally the micromechanical properties) of material surfaces. These properties are expected to affect the interfacial processes cooperatively, i.e., there are likely synergistic effects between and among them: The surface is "recognized" by the biological system through the combined chemical and topographic pattern of the surface, and the viscoelastic properties. In this presentation, the development indicated above is discussed briefly, and current R&D in this area is illustrated with a number of examples from our own research. The latter include micro- and nanofabrication of surface patterns and topographies by the use of laser machining, photolithographic techniques, and electron beam and colloidal lithographies to produce controlled structures on implant surfaces in the size range 10 nm to 100 microns. Examples of biochemical modifications include mono- or lipid membranes and protein coatings on different surfaces. A new method to evaluate, e.g., biomaterial-protein and biomaterial-cell interactions--the Quartz Crystal Microbalance--is described briefly.
325 citations
TL;DR: In this article, Lewis acid mediated hydrosilylation of alkynes and alkenes on non-oxidized hydride-terminated porous silicon derivatizes the surface with alkenyl and alkyl functionalities, respectively.
Abstract: Lewis acid mediated hydrosilylation of alkynes and alkenes on non-oxidized hydride-terminated porous silicon derivatizes the surface with alkenyl and alkyl functionalities, respectively. A very broad range of chemical groups may be incorporated, allowing for tailoring of the interfacial characteristics of the material. The reaction is shown to protect and stabilize porous silicon surfaces from atmospheric or direct chemical attack without compromising its valuable material properties such as high porosity, surface area and visible room-temperature photoluminescence. The reaction is shown to act on alkenes and alkynes of all possible regiochemistries (terminal and internal alkynes; mono-, cis- and trans-, di-, tri-, and tetrasubstituted alkenes). FTIR as well as liquid- and solid-state NMR spectroscopies show anti-Markovnikov addition and cis stereochemistry in the case of hydrosilylated terminal alkynes. Material hydrosilylated with long-chain hydrophobic alkynes and alkenes shows a substantially slower surface oxidation and hydrolysis rate in air as monitored by long-term FTIR monitoring and chemography. BJH and BET measurements reveal that the surface area and average pore size of the material are reduced only slightly after hydrosilylation, indicating that the porous silicon skeleton remains intact. Elemental analysis and SIMS depth profiling show a consistent level of carbon incorporation throughout the porous silicon which demonstrates that the reaction occurs uniformly throughout the depth of the film. The effects of functionalization on photoluminescence were investigated and are shown to depend on the organic substituents.
308 citations
TL;DR: Water-repellent surfaces have been prepared by exposing Si substrates with a hydroxylated surface oxide to fluoroalkyl silane (FAS) vapor as mentioned in this paper.
Abstract: Water-repellent surfaces have been prepared by exposing Si substrates with a hydroxylated surface oxide to fluoroalkyl silane (FAS) vapor. Since this chemical vapor surface modification (CVSM) is based on the chemical reaction between organosilane molecules and hydroxyl groups at the oxide surface, prior to CVSM, the substrate surface was completely hydroxylated by irradiating in air with a 172-nm ultraviolet light until the water contact angle of the surface became almost 0°. Under atmospheric pressure, the substrate was then exposed to vapor of an FAS precursor, that is, one of three types of FAS having different perfluoroalkyl chain lengths [CF3(CF2)nCH2CH2Si(OCH3)3, where n = 0, 5, or 7, referred to as FAS-3, FAS-13, and FAS-17, respectively]. The FAS molecules chemically reacted with the hydroxyl groups on the substrate surface and adsorbed onto it, forming a thin layer of less than 2 nm in thickness. The water repellency of the substrate surface increased with an increase in perfluoroalkyl chain len...
299 citations
TL;DR: Ion beam surface modification has shown great potential for improving the tribological behavior as well as surface mechanical properties of polymeric materials as mentioned in this paper, and the state-of-the-art of ion beam surface modifications for improving tribological and mechanical properties is assessed through a referenced literature review, and the ion-polymer interaction mechanisms involved in ion beam modification of polymers are briefly discussed.
Abstract: Ion beam surface modification has shown great potential for improving the tribological behaviour as well as surface mechanical properties of polymeric materials. As a result, the past few years have seen many advances in the field of ion beam surface modification of polymeric materials in terms of applying conventional ion beam techniques to various types of polymers, and introducing innovative plasma-enhanced ion implantation techniques. In this paper, the main wear mechanisms of polymeric materials are first overviewed; the state-of-the-art of ion beam surface modification of polymeric materials for improving tribological as well as mechanical properties is assessed through a referenced literature review; the ion–polymer interaction mechanisms involved in ion beam modification of polymers are briefly discussed; finally, key areas for future development are suggested.
248 citations
31 Jul 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the chemical properties of metallic biomaterials used for artificial joints, bone plates, and dental implants in vivo are discussed based on empirical data, focusing on the maturation of surface oxide film on titanium and the film's destruction and regeneration in body fluids.
Abstract: The chemical properties of metallic biomaterials used for artificial joints, bone plates, and dental implants in vivo are discussed based on empirical data, focusing on the maturation of surface oxide film on titanium and the film’s destruction and regeneration in body fluids. It is reviewed the behavior of metallic materials in vivo and how to modify the surface of biomaterials to improve corrosion and wear resistance and bone conductivity. Effect of calcium ion implantation into titanium for improvement of its bone conductivity is given as an example.
230 citations
TL;DR: These results provide a foundation for using low-temperature plasma-induced grafting on PES with a variety of other molecules, including other hydrophilic monomers besides NVP, charged or hydrophobic molecules, binding domains, and biologically active molecules such as enzymes and ribozymes.
Abstract: Low-temperature helium plasma treatment followed by grafting of N-vinyl-2-pyrrolidone (NVP) onto poly(ether sulfone) (PES) ultrafiltration (UF) membranes was used to modify commercial PES membranes. Helium plasma treatment alone and post-NVP grafting substantially increased the surface hydrophilicity compared with the unmodified virgin PES membranes. The degree of modification was adjusted by plasma treatment time and polymerization conditions (temperature, NVP concentration, and graft density). The NVP-grafted PES surfaces were characterized by Fourier transform infrared attenuated total reflection spectroscopy and electron spectroscopy for chemical analysis. Plasma treatment roughened the membrane as measured by atomic-force microscopy. Also, using a filtration protocol to simulate protein fouling and cleaning potential, the surface modified membranes were notably less susceptible to BSA fouling than the virgin PES membrane or a commercial low-protein binding PES membrane. In addition, the modified membranes were easier to clean and required little caustic to recover permeation flux. The absolute and relative permeation flux values were quite similar for the plasma-treated and NVP-grafted membranes and notably higher than the virgin membrane. The main difference being the expected long-term instability of the plasma treated as compared with the NVP-grafted membranes. These results provide a foundation for using low-temperature plasma-induced grafting on PES with a variety of other molecules, including other hydrophilic monomers besides NVP, charged or hydrophobic molecules, binding domains, and biologically active molecules such as enzymes and ribozymes. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1699–1711, 1999
TL;DR: In this article, a hydrogen-terminated Si(111) surface has been covalently modified by UV irradiation in the presence of ethyl undecylenate leading to a Si (111)-C10H20CO2Et surface.
Abstract: A hydrogen-terminated Si(111) surface has been covalently modified by UV irradiation in the presence of ethyl undecylenate leading to a Si(111)-C10H20CO2Et surface. It is possible to carry out a diverse range of chemical manipulations of the ester group on the surface. For example, reduction with sodium borohydride provides a surface terminated with a primary alcohol. Reaction with an alkyl Grignard reagent gives a tertiary alcohol that can be acylated with acetyl chloride. Finally, hydrolysis of the ester leads to a carboxylic acid terminated surface that can be coupled to an amino acid using a standard solid phase amide coupling protocol. The surface density of the ester function can be controlled by dilution of the reacting ester with a long-chain alkene. This has the beneficial effects of minimizing the disruption of the alkyl chain packing in the monolayers and avoiding steric blocking of the ester group. It is expected that the ability to precisely control the average distance between large biomolec...
02 May 1999-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this paper, an overview of plasma surface modification of polymers is presented, in which the main variables for process control, illustrated by examples, are identified and compared with other competing technologies, especially those based on ultraviolet radiation.
Abstract: The use of low-pressure plasmas for materials processing, pioneered by the semiconductor industry since the 1960s, is now also a commercial reality in technologies which make extensive use of plastics (automotive, aerospace, packaging, pharmaceutical, textile, and other industries). A large fraction of these processes involve the surface modification of polymers for improved adhesion, and many of these use air or oxygen plasma to incorporate polar functional groups into the polymer surfaces. Interaction mechanisms between a plasma and a polymer surface are very complex, for they include synergistic effects of physical bombardment by energetic particles and by ultraviolet photons, and resulting chemical reactions at and below the surface. In this article we present an overview of plasma surface modification of polymers, in which we identify the main variables for process control, illustrated by examples. We then show, on hand of a series of specially designed experiments, how the effects of ultraviolet photons generated in the plasma can be assessed separately from those of other energetic and reactive species, especially in the case of oxidizing plasmas. Finally, we comment on the merits and drawbacks of industrial plasma processes in comparison with other competing technologies, especially those based on ultraviolet radiation.
TL;DR: This work describes a method for coupling cell adhesion peptides to hydrophobic materials for the purpose of controlling surface peptide density while simultaneously preventing nonspecific protein adsorption.
TL;DR: A methodology for the formation and derivatization of self-assembled monolayers (SAMs) of alkyl phosphonic acids on common engineering metals such as steel, stainless steel, aluminum, copper, and brass is described in this paper.
Abstract: A methodology for the formation and derivatization of self-assembled monolayers (SAMs) of alkyl phosphonic acids on common engineering metals such as steel, stainless steel, aluminum, copper, and brass is described This methodology is shown to be a versatile route for surface modification of such substrates α,ω-Metal bisphosphonate SAMs are shown to be receptive to complexation by organic acids and acid-containing polymers such as fluoropolymers and ethylene-co-methacrylic acid This latter attribute is exploited in the construction of polymer/SAM/metal interfaces of surprising durability The durability of the interface is a strong function of the SAM chain length
TL;DR: The surface modification of mixed Si-Al oxides by silylation over a wide range of pore sizes is discussed in this article. But the authors focus on the porosity, the adsorption characteristics and thermodynamic background of these modifications.
TL;DR: To improve the surface blood compatibility of polysulfone (PSf) membranes, novel polymeric additives which have suitable blood compatibility were prepared which significantly reduced plasma protein adsorption compared with that of the PSf membrane.
TL;DR: The dissolution-deposition cycle behavior of Li metal electrodeposited in nonaqueous electrolyte containing a small amount of HF was investigated in this article, where it was found that the coulombic efficiency of Li deposition-dissolution during cycling was much improved by the addition of HF.
Abstract: The dissolution‐deposition cycle behavior of Li metal electrodeposited in nonaqueous electrolyte containing a small amount of HF was investigated. In the first deposition process, Li particles with a smooth hemispherical shape were deposited on Ni in 1.0 M carbonate containing HF. The morphology of these fine Li particles is due to electrodeposition via migration of ions through a thin and compact surface film consisting of a bilayer, which was produced via surface modification by HF. After the first dissolution process, a residual film was observed on the entire surface of the Ni substrate. This residual film is derived from the surface film on the Li particles. Moreover, the residual film continuously accumulated on the electrode during the cycling. On the other hand, it was found that the coulombic efficiency of Li deposition‐dissolution during cycling was much improved by the addition of HF. Unfortunately, the formation of dendritic Li was observed after the 45th cycle, suggesting that the accumulated thick residual film on the Li surface inhibits the supply of HF to the Li surface during the deposition process. © 1999 The Electrochemical Society. All rights reserved.
TL;DR: Current available physical surface modification methods for food packaging polymers are reviewed from the food packaging perspective, and an overview of economic aspects of sophisticated surface modification techniques, including ion beam, plasma, and laser treatments is presented.
Abstract: Continued innovations in the polymer industry have made polymer surface modification methods a subject of intense research. The importance and necessity of surface modification of plastics are explained, and the advantages of physical surface treatments over the less-sophisticated chemical methods are outlined. Currently available physical surface modification methods for food packaging polymers are reviewed from the food packaging perspective. These physical surface modification methods include flame, corona discharge, UV, gamma-ray, electron beam, ion beam, plasma, and laser treatments. The principle of operation of each method is briefly described, and the advantages and disadvantages of each technique are cited. The extent to which each of these methods can produce the specific modifications desired is discussed. Furthermore, the effects of each treatment on barrier, mechanical, and adhesion properties of food packaging polymers are also examined. Finally, an overview of economic aspects of sophisticated surface modification techniques, including ion beam, plasma, and laser treatments, is presented.
TL;DR: In this article, the anti-wear ability of DDP-nano Cu as additive in liquid paraffin was examined with a four-ball machine and it was found that the modified copper nanoparticles showed different antiwear ability depending on their particle size.
TL;DR: A review of applications of the ion-beam process in modifying the surface of biomaterials, as well as the effects induced by ionbeam irradiation to crop seeds, cells and microbes can be found in this article.
Abstract: Biomaterials modification by ion-beam processing is becoming popular for improving medical device function, biocompatibility and as a new mutation breeding method. Ion-beam-based processes, such as ion implantation and ion-beam assisted deposition (IBAD) can provide beneficial surface layers with desirable properties without detrimentally affecting the bulk properties. Ion implantation has been successful in biomaterials modification, such as in improving the wear resistance of artificial joint components, in improving wettability, anticoagulability, anticalcific behavior of biomedical polymers, and in minimizing biofouling of medical devices, etc. IBAD has been used to prepare hydroxyapatite coatings with high adhesive strength on substrates of several implant materials. Biocompatible diamond-like carbon coatings and C–N films, antibacterial coatings and sealant coatings have also been produced by this technique. This paper reviews the present status of applications of the ion-beam process in modifying the surface of biomaterials, as well as the effects induced by ion-beam irradiation to crop seeds, cells and microbes.
TL;DR: In this paper, a review of the role of interaction in composite properties is presented, where surface treatments are divided into four arbitrary groups and discussed accordingly, i.e., non-reactive and reactive treatment, application of functionalized polymers and introduction of a soft interlayer around the particles.
Abstract: This review emphasizes the role of interactions in particulate filled composites. In an introductory section a general view is given about the factors influencing composite properties. Two basic type of interactions must be considered: particle/particle and matrix/filler interaction. The effect of the former is detrimental to composite properties, it decreases strength and impact resistance. The occurrence and extent of aggregation is determined by the relative adhesion and shear forces during homogenization. Due to matrix/filler interaction an interphase forms spontaneously in the composite with properties different from those of both components. The amount and characteristics of the interphase strongly influence composite properties. The strength of adhesion between the components can be characterized by thermodynamic quantities, mainly by the reversible work of adhesion. The most important techniques used for the estimation of the strength of interaction and the properties of the interphase are briefly reviewed. The modification of interactions is achieved through the surface treatment of the filler. Surface treatments are divided into four arbitrary groups and are discussed accordingly, i.e. non-reactive and reactive treatment, application of functionalized polymers and introduction of a soft interlayer around the particles. The practical relevance of interactions and their modification is also mentioned in the last section.
TL;DR: In this article, a phenyl-silane monolayer is created on the substrate's oxide surface by using phenyltrichlorosilane as the silane coupling agent.
Abstract: A method of surface functionalization of ceramics with monolayers and surface grafted polymer layers is described. A phenylsilane monolayer is created on the substrate's oxide surface by using phenyltrichlorosilane as the silane coupling agent. To control the formation of the monolayer and ensure the growth of a dense, homogeneous layer, the ceramic surface is first dried and then a controlled amount of water is adsorbed onto it, and a hindered organic base is added to the phenyltrichlorosilane solution to absorb acid generated in the reaction of the silane coupling agent with hydroxyl groups on the ceramic surface. This procedure results in dense homogeneous phenylsilane monolayers on a variety of surfaces, including silicon, Pt/PtO, and quartz. These layers can now be functionalized by addition of triflic acid, which removes the phenyl ring as benzene, and introduction of a nucleophile. Monolayers of −C⋮CH, −OCH2CF3, [(OCH2CH2)2O], −OCH2CF2CF3, and −O(CH2)6NH2 were generated in this fashion, all proving...
TL;DR: In this article, the improvement of properties of clay-rubber composites by acid activation and surface modification of the clay is discussed, showing that acid-treated clays show a higher surface activity and a stronger combining ability with silane coupling agents.
TL;DR: This new method is fast and efficient, and achieves high surface coverage with functionalized and nonfunctionalized alkyl and benzyl groups within minutes.
Abstract: Functionalization of hydride-terminated porous and single-crystal silicon surfaces with organic species is accomplished by electrochemical reduction of organo iodides and organo bromides (see scheme). This new method is fast and efficient, and achieves high surface coverage with functionalized and nonfunctionalized alkyl and benzyl groups within minutes.
TL;DR: In this paper, an internal magnetic abrasive finishing process was proposed for producing highly finished inner surfaces of tubes used in critical applications including clean gas or liquid piping systems, and the microscopic changes in the surface texture resulting from processing were examined.
TL;DR: The results suggest that an optimized PEO surface treatment may be effective in reducing inflammatory cell adhesion and possible degradation during the inflammatory response to an implanted biomedical device.
Abstract: Surface immobilized polyethylene oxide (PEO) has been shown to efficiently reduce protein adsorption and cellular adhesion, resulting in a biologically passive surface. To explore the in vitro effects of surface immobilized PEO on the human inflammatory cells, macrophages, and foreign body giant cells (FBGCs), we developed a diisocyanate-based method for coupling PEO to amine-modified glass, a surface previously shown to enhance macrophage adhesion and FBGC formation. Contact angle analysis and X-ray photoelectron spectroscopy confirmed the presence of PEO molecules bound to the surface and revealed that PEO molecular weight significantly influenced the efficiency of PEO coupling. We used a 10-day human monocyte culture protocol to demonstrate that the presence of surface coupled PEO molecules does not significantly decrease initial monocyte density or monocyte-derived macrophage density after 3 days. However, PEO-coupled surfaces significantly reduced long-term monocyte-derived macrophage density and virtually eliminated interleukin-4-induced FBGC formation observed at day 10. The cellular response to these PEO-coupled surfaces was related to the molecular weight of the PEO chains, which was varied between 200 Da and 18.5 kDa. These results suggest that an optimized PEO surface treatment may be effective in reducing inflammatory cell adhesion and possible degradation during the inflammatory response to an implanted biomedical device.
TL;DR: In this article, a comparison of several approaches to produce homogeneously finished polymer surfaces is presented, focusing on plasma grafting, and the influence of the gases used to activate the polymer surface for grafting carboxyl groups is also discussed.
Abstract: Tailor-made surfaces are needed for many applications concerning medical equipment or life-science polymer material. The polymers should only reveal one type of functionality (carboxyl groups), homogeneously distributed with a defined density over their total surface. Many attempts have been made to obtain those monofunctional surfaces on polymers via plasma treatments. The commonly used plasma treatment (with oxygen) results in a host of different functionalities often with a low stability. The latter is caused by damaging processes also occuring during the plasma treatment (fragmentation by charged particle bombardment or radiation damage). Therefore, it is desirable to minimize or, if possible, to completely avoid these effects. In principle, two kinds of strategies are used: first, minimising the applied energy (e.g. use of low power or pulsed powered plasmas) and minimising the kind and density of damaging particles during treatment in the plasma; second, separating substrate functionalisation from plasma in space (down stream) or in time (grafting). Both methods lead to a more homogenous distribution of functionalities and a better retention of the precursor structure. The aim of this contribution is to give a comparison of several approaches to produce homogeneously finished polymer surfaces. Attention is focused on plasma grafting. As substrate, polypropylene is chosen because of its widespread applications and its simple chemical composition, which makes observation of grafting yields easy to analyse. As functional groups, hydroxyl, carboxyl and epoxy groups are chosen. These are introduced by direct plasma treatment and also by grafting methods. Functional groups are observed by ESCA and IR measurements. The influence of the gases used to activate the polymer surface for grafting carboxyl groups is also discussed.
01 Jan 1999
TL;DR: In this paper, surface modification of fumed silica, its particle size distribution, and electrophoretic mobility in aqueous suspensions highly efficient acid-gas-removing shaped fibre filters maximizing the extent of hexamethyldisilazane reaction with silica.
Abstract: Siloxane-anchored monolayers as templates for oxide film deposition synthesis and characterization of self-organized microstructures with chemically active surfaces and evaluation of their technical utility Thiol-modified phthalocyanines and their self-assembled monolayers on gold surfaces modification of particle surfaces by grafting of functional polymers grafting processes studied with a nanotip - silane molecules and polymers grafted on silica and silanized silica surfaces multilayer dendrimer-poly(anhydride) nanocomposite films conductivity enhancement of polymer composites through admicellar polymerization of pyrrole on particulate surfaces filler surface characterization and its relation to mechanical properties of polymer composites grafting of crystalline polymers onto carbon black surface and its application for gas sensors surface modifications to support materials for HPLC, HPCE and electromatography synthesis, characterization and application of new bonded phases for HPLC microscale synthesis and screening of combinatorial libraries of new chromatographic stationary phases the alkylation of drugs at ion exchange sites on the surface of solid phase extraction columns connection between surface modification of fumed silica, its particle size distribution, and electrophoretic mobility in aqueous suspensions highly efficient acid-gas-removing shaped fibre filters maximizing the extent of hexamethyldisilazane reaction with silica - an experimental design study surface modification of highly dispersed titania/silica, and efficiency of their applications surface modification of micron-size powders by a plasma polymerization process effect of water plasma on silica surfaces - synthesis, characterization and applications. (Part contents)
TL;DR: Self-assembled monolayers of alkylsiloxanes supported on poly(dimethylsiloxane) rubber were used as model systems to study the relation between blood compatibility and surface composition and were found to be the least thrombogenic of all the surfaces tested.