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Polymer Coating (polymer + coating)
Selected AbstractsConductive Polymer Coating on Nonconductive Ceramic Substrates for Use in the Electrophoretic Deposition ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2008Tetsuo Uchikoshi Uniform coating and line patterning of a conductive polypyrrole (Ppy) film on nonconductive ceramic materials were performed for use as substrates in the electrophoretic deposition (EPD) process. The Ppy was synthesized by chemical oxidation in the pyrrole solution. Direct shaping or line patterning of alumina or zirconia particles by EPD was carried out using the Ppy films as cathodes. [source] Solvent-Resistant PDMS Microfluidic Devices with Hybrid Inorganic/Organic Polymer CoatingsADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Bo-Yeol Kim Abstract This study presents a method for the fabrication of solvent-resistant poly(dimethylsiloxane) (PDMS) microfluidic devices by coating the microfluidic channel with a hybrid inorganic/organic polymer (HR4). This modification dramatically increases the resistance of PDMS microfluidic channels to various solvents, because it leads to a significant reduction in the rate of solvent absorption and consequent swelling. The compatibility of modified PDMS with a wide range of solvents is investigated by evaluating the swelling ratio measured through weight changes in a standard block. The HR4-modified PDMS microfluidic device can be applied to the formation of water-in-oil (W/O) and oil-in-water (O/W) emulsions. The generation of organic solvent droplets with high monodispersity in the microfluidic device without swelling problems is demonstrated. The advantage of this proposed method is that it can be used to rapidly fabricate microfluidic devices using the bulk properties of PDMS, while also increasing their resistance to various organic solvents. This high compatibility with a variety of solvents of HR4-modified PDMS can expand the application of microfluidic systems to many research fields. [source] Porous Polymer Coatings: a Versatile Approach to Superhydrophobic SurfacesADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Pavel A. Levkin Abstract Here, a facile and inexpensive approach to superhydrophobic polymer coatings is presented. The method involves the in situ polymerization of common monomers in the presence of a porogenic solvent to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The method is applicable to a variety of substrates and is not limited to small areas or flat surfaces. The polymerized material can be ground into a superhydrophobic powder, which, once applied to a surface, renders it superhydrophobic. The morphology of the porous polymer structure can be efficiently controlled by composition of the polymerization mixture, while surface chemistry can be adjusted by photografting. Morphology control is used to reduce the globule size of the porous architecture from micro down to nanoscale thereby affording a transparent material. The influence of both surface chemistry as well as the length scale of surface roughness on the superhydrophobicity is discussed. [source] Self-Healing Polymers: Self-Healing Polymer Coatings (Adv. Mater.ADVANCED MATERIALS, Issue 6 20096/2009) Dramatic reduction in corrosion of a steel plate coated with a self-healing coating (right) as compared to a conventional coating is demonstrated. Two samples were scratched and placed in 5% NaCl for 5 days. The background is an optical image (2× magnification), in the foreground is an SEM image of the scratch. In the self-healing sample, the scratch has almost completely self-healed, while in the control sample, the scratch remains all the way down to the substrate, as reported by Paul Braun and co-workers on p.645. [source] Self-Healing Polymer CoatingsADVANCED MATERIALS, Issue 6 2009Soo Hyoun Cho Self-healing coatings that autonomically repair and prevent corrosion of the underlying substrate are created through dispersion of microencapsulated healing agents in a polymer film. Following a damage event, these healing agents are released into the damaged region, passivating the substrate. This approach to self-healing coatings is quite general, and is effective for both model and industrially important coating systems. [source] Cover Picture: Multipotent Polymer Coatings Based on Chemical Vapor Deposition Copolymerization (Adv. Mater.ADVANCED MATERIALS, Issue 12 200612/2006) Abstract The cover shows that chemical vapor deposition can be used to prepare copolymer thin films, on varying substrates, that can bind two different ligands with high selectivity. In work reported by Lahann and co-workers on p.,1521, the actual ligand ratios on the surface can be controlled by varying the copolymer composition. This technology may find applications in biomedical devices, high-throughput screening platforms, microfluidic analysis devices, and diagnostic platforms. [source] Gold Nanoparticle-Hybridized "Nano-Sponge" Polymer Coatings to Enhance the Reliability and Sensitivity of BiosensorsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 13 2009Hyung-Jun Jeong Abstract We have created a new functional biosensor coating composed of polyelectrolyte multilayers containing gold nanoparticles. This gold-hybridized polyelectrolyte multilayer film possesses a stable nanoporous structure under physiological conditions. Antibody molecules were successfully conjugated onto the gold nanoparticles within the film. This functional coating successfully extinguished false signals from non-specific binding of proteins and cells and also provided highly enhanced detection sensitivity. Furthermore, the drastic differences in protein and cellular adhesion properties between a chip coated with the nanoporous PEM film and a bare chip demonstrate that morphological control of biological interactions on chip surfaces is possible. [source] Novel negatively charged tentacle-type polymer coating for on-line preconcentration of proteins in CEELECTROPHORESIS, Issue 4 2009Liang Xu Abstract A novel negatively charged tentacle-type polymer-coated capillary column was fabricated and applied for on-line extraction and preconcentration of proteins. The polymer coating was prepared by glycidyl-methacrylate graft polymerization in a silanized capillary column and the following sulfonic acid group functionalization. It had high surface area and offered high phase ratio for protein adsorption. In addition, the polymer-coated capillary column provided more stable EOF than a bare uncoated capillary. These features of the polymer coating facilitated the extraction of proteins through electrostatic interactions. This was used to extract proteins. The extracted analytes were then desorbed and focused by EOF in the direction opposite to the sample injection flow for subsequent CE. With this procedure, over 1500-fold sensitivity enhancement was realized for myoglobin (MB) as compared with a normal capillary zone electrophoresis. By comparison of the peak areas of the enriched protein, it was found that the polymer-coated column could capture proteins about 30 times more than the uncoated column. In addition, the separation of a protein mixture containing 0.4,,g/mL of MB and 0.4,,g/mL of insulin was demonstrated by the on-line preconcentration and electrophoretic separation with the polymer-coated column. [source] Preparation and Characterization of Gallium Releasing 3-D Alginate Coated 45S5 Bioglass® Based Scaffolds for Bone Tissue Engineering,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Viviana Mourińo Abstract The aim of this work was to develop functional three-dimensional scaffolds based on Bioglass® derived glass,ceramics for bone tissue engineering (TE) with prophylaxis effect against infections. The highly porous scaffolds were fabricated by the foam replication technique and then coated with sodium alginate crosslinked with Ga3+. It was confirmed that the polymer coating did not affect the interconnectivity of the scaffold pore structure. The resulting composite scaffold exhibited antibacterial effect and improved mechanical properties as well as high bioactivity. The novel Ga3+ loaded 45S5 Bioglass®-based scaffolds coated with alginate are promising candidates for bone TE applications. [source] Delivery of Two-Part Self-Healing Chemistry via Microvascular NetworksADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Kathleen S. Toohey Abstract Multiple healing cycles of a single crack in a brittle polymer coating are achieved by microvascular delivery of a two-part, epoxy-based self-healing chemistry. Epoxy resin and amine-based curing agents are transported to the crack plane through two sets of independent vascular networks embedded within a ductile polymer substrate beneath the coating. The two reactive components remain isolated and stable in the vascular networks until crack formation occurs in the coating under a mechanical load. Both healing components are wicked by capillary forces into the crack plane, where they react and effectively bond the crack faces closed. Healing efficiencies of over 60% are achieved for up to 16 intermittent healing cycles of a single crack, which represents a significant improvement over systems in which a single monomeric healing agent is delivered. [source] On the peel behavior of polymer coating,steel system: Effect of hygrothermal agingADVANCES IN POLYMER TECHNOLOGY, Issue 3 2010N. Guermazi Abstract This paper describes the development and application of a new peel protocols for the evaluation of adhesion of a flexible-to-rigid assembly. The developed apparatus allows simulating and predicting the delamination of the polymer coating from the steel substrate. The effect of certain test parameters such as a peel angle and peel speed was discussed. The durability of the retained assembly was equally investigated by considering an accelerated hygrothermal aging. The interfacial damages after conditioning and peel tests were characterized. Using two peeling angles of 90° and 180°, no significant difference was observed in terms of peel responses. The interface behavior seems to be not sensitive to the peel angle. However, an increase in the peel rate induces an increase in the peel strength. The characterization of the interface exhibits two mechanisms: The delamination process of the polymer coating is characterized by cohesive and mixed rupture, respectively, at low and high peel rates. Studying the effects of aging and coating defects on the interface behavior displays a continuous loss of adhesion of the polymer coating especially when it presents physical defects. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:185,196, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20188 [source] Poly(O -anisidine) coatings electrodeposited onto AL-2024: Synthesis, characterization, and corrosion protection evaluationADVANCES IN POLYMER TECHNOLOGY, Issue 4 2004Kunal Shah Abstract Poly(O -anisidine) coating was successfully electrodeposited onto Al-2024. Cyclic voltammetry and reflection absorption infrared spectroscopy (RAIR) analysis were carried out in order to fully understand the formation and structure of the resulting polymer coating. RAIR spectrum showed the characteristics peaks of poly(O -anisidine). As the reaction time was varied, the CV peak shifted from 0.75 to 0.81 V vs. SCE suggesting that a change in structure of the polymer from a reduced state to a partially oxidized form has occurred. UV spectrum showed two peaks at 320 and 620 nm suggesting the presence of conjugation on the polymer backbone. The deposition of the poly(O -anisidine) onto the substrate was controlled by nucleation and growth mechanism. DC polarization technique was used to evaluate the corrosion protection offered by poly(O -anisidine) coatings. Preliminarily data shows that these coatings help to ennoble the surface of the substrate. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 291,297, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20024 [source] A novel approach to excellent UV protecting cotton fabric with functionalized MWNT containing water vapor permeable PU coatingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2007S. Mondal Abstract This research paper presented a novel approach of developing excellent protection from ultraviolet (UV) radiation of cotton fabrics by means of water vapor permeable (WVP) coatings containing multiwall carbon nanotube (MWNT), a stable and strongly UV absorbing species. The WVP of MWNT containing UV protective coatings of the present development are formed from solution polymer of hydrophilic polyurethane (HPU). MWNTs were dispersed in HPU solution by functionalization of MWNT. The nanotube containing HPU coating shows excellent protection against UV radiation, with only 1 wt % of MWNT (calculated based on solid content of the polymer), a UV Protection Factor (UPF) of 174 and with 2.5 wt % of MWNT a UPF of 421 was obtained, which stated excellent protection (UPF ,50) according to the Australian/New Zealand standards. Scanning electron micrographs of coated fabrics surface showed a film like polymer coating, confirming the fabric surface was successfully coated by polyurethane. The coated fabrics would maintain very good water vapor permeability, hence confirmed the wearing comfort. Room temperature (20,23°C) range soft segment crystal melting of HPU enhances the permeability of coated fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3370,3376, 2007 [source] Preparation and evaluation of a novel delayed-onset sustained-release system of propranolol hydrochlorideJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2008Xue-mei Feng The objective of this work was to prepare and evaluate a new delayed-onset sustained-release system, comprising a sustained-release core tablet with hydroxypropyl methylcellulose as polymer matrix and an ethylcellulose/Eudragit L coating capable of delaying the drug release. The sustained core containing propranolol hydrochloride as the model drug was prepared by granulate tableting and the polymer coating was applied in a computer-controlled coating pan. The dissolution tests demonstrated that the in-vitro drug release was pH-dependent with sufficient gastric resistance, and the lag time (t10%) could be controlled by adjusting the coating level. Three dosage forms including commercial tablet, sustained-release tablet and the delayed-onset sustained-release tablet were administrated to six beagle dogs and the plasma levels of propranolol hydrochloride were measured with high-performance liquid chromatography. The delayed-onset sustained-release tablet had a lag time of 3.0 h in-vitro and 3.5 h in-vivo, and a tmax of 7.0 h. The relative bioavailability for delayed-onset sustained-release tablet was 96.98% compared with commercial tablets. The results indicate that the new propranolol delayed-onset sustained-release system could achieve a relatively constant drug release followed by a programmed lag time, and this may provide a promising drug delivery form for chronopharmacotherapy of certain cardiovascular diseases. [source] Response Characteristics of Thermoresponsive Polymers Using Nanomechanical Cantilever SensorsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2009Calvin Bradley Abstract We investigated coatings of thermally responsive thin polymer films prepared on nanomechanical cantilever sensor (NCS): (i) a PNIPAM brush, and (ii) an interlinked ppDEA polymer. Upon heating from 22 to 50,°C in water, a minimum in the differential deflection between 31.9,±,1.7,°C (PNIPAM) and 47.7,±,1.9,°C (ppDEA) was measured. The minimum in differential deflection can be associated with the lower critical solution temperature (LCST) of the films. Below the LCST the NCS deflection corresponds to a bending toward the thermally responsive polymer film side, associated to dehydration. At higher temperature, the deflection was reversed, i.e., away from the polymer coating. This response is mainly attributed to a bimaterial effect between the collapsed polymer and the NCS material. The LCST of the PNIPAM brush layer and the ppDEA film were close to that reported for the bulk polymers. [source] Cover Picture: Plasma Process.PLASMA PROCESSES AND POLYMERS, Issue 8 2005Polym. Cover: The Figure shows the X-ray photoelectron spectra of the nitrogen 1s core levels and the near edge X-ray fine structure nitrogen K edge of plasma polymers and plasma co-polymers prepared from allylamine and mixtures of acrylic acid and allylamine. Molecular models of allylamine, acrylic acid and allylammonium acrylate salt are shown to illustrate the chemistry. This is shown on a background of a micrograph of melanocytes cultured on a plasma polymer coating. The micrograph has been artificially colourised. Further details can be found in the Full Paper by A. J. Beck,* J. D. Whittle, N. A. Bullett, P. Eves, S. Mac Neil, S. L. McArthur, and A. G. Shard on page 641. [source] In-Situ Preparation of Polymer-Coated Alumina Nanopowders by Chemical Vapor SynthesisCHEMICAL VAPOR DEPOSITION, Issue 1 2003M. Schallehn Abstract Nanocrystalline alumina particles coated with polyethylene have been prepared by a two-step chemical vapor synthesis (CVS) process using a hot-wall reactor to synthesize the nanocrystalline alumina core, and a RF plasma reactor for the subsequent polymer coating. The particle radius is about 4,nm, with the radius of the ceramic core being about 2.5,nm and the coating thickness about 1.5,nm. The powders have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer,Emmett,Teller (BET), small-angle neutron scattering (SANS), and high-resolution transmission electron microscopy (HRTEM). [source] Porous Polymer Coatings: a Versatile Approach to Superhydrophobic SurfacesADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Pavel A. Levkin Abstract Here, a facile and inexpensive approach to superhydrophobic polymer coatings is presented. The method involves the in situ polymerization of common monomers in the presence of a porogenic solvent to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The method is applicable to a variety of substrates and is not limited to small areas or flat surfaces. The polymerized material can be ground into a superhydrophobic powder, which, once applied to a surface, renders it superhydrophobic. The morphology of the porous polymer structure can be efficiently controlled by composition of the polymerization mixture, while surface chemistry can be adjusted by photografting. Morphology control is used to reduce the globule size of the porous architecture from micro down to nanoscale thereby affording a transparent material. The influence of both surface chemistry as well as the length scale of surface roughness on the superhydrophobicity is discussed. [source] Coaxial Electrospinning of Self-Healing CoatingsADVANCED MATERIALS, Issue 4 2010Jeong-Ho Park Self-healing polymer coatings are formed by electrospinning bead-on-string healing agent filled capsules onto a substrate followed by infilling of a polymer matrix. Upon damage to the self-healing coating, liquid healing agents are released from the ruptured beads passivating the damaged region, preventing it from corroding as shown through microscopy, electrochemistry, and corrosion testing. [source] Interaction of endothelial cells with self-assembled monolayers for potential use in drug-eluting coronary stentsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Gopinath Mani Abstract Drug-eluting stents (DES) are implanted in patients to treat in-stent restenosis. Commercially available DES use polymers for coating and releasing drugs. Several studies have showed that polymer coatings cause adverse reactions. Delayed endothelialization of polymer-coated DES leads to late stent thrombosis. Recently, the potential for using self-assembled monolayers (self-assembled monolayers (SAMs),organic constructs composed of (a) chemical groups which attach to metal surfaces, (b) long hydrocarbon chains, and (c) terminal functional groups) as an alternate drug delivery system for coronary stents has been demonstrated. In this study, the interaction of human aortic endothelial cells (HAECs) with SAMs and therapeutic SAMs (therapeutic self-assembled monolayers (TSAMs),SAMs derivatized with the drug, flufenamic acid) was investigated. HAECs were cultured on plain glass, control, SAMs-, and TSAMs-coated titanium (Ti) and gold (Au) specimens. The viability and proliferation of HAECs were investigated using MTT colorimetric assay. The adhesion of HAECs on SAMs and TSAMs was equivalent to that of control metal surfaces and superior to that of plain glass surfaces. The cells continued to proliferate on both SAMs and TSAMs even though the rate of proliferation was slower than plain glass or control-Ti. The spreading of HAECs on TSAMs with typical polygonal shape indicated that these surfaces are conducive to endothelialization. The expression of surface adhesion protein, platelet endothelial cell adhesion molecule-1, on TSAMs indicated that the endothelial cells preserved their phenotype on these surfaces. Thus, this study demonstrated that SAMs and TSAMs do not elicit an adverse response from endothelial cells in in vitro conditions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Properties of nisin-incorporated polymer coatings as antimicrobial packaging materialsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2002Young-Min Kim Abstract Nisin was incorporated into binder solutions of acrylic polymer and vinyl acetate-ethylene co-polymer, and then coated on to paper. Diffusive migration of incorporated nisin and the antimicrobial activity of the polymer coatings were investigated in order to understand the way of controlling nisin migration and the extent of microbial suppression by the coated paper. Vinyl acetate,ethylene co-polymer exhibited a faster rate and higher degree of migration into aqueous food simulant solutions compared to acrylic polymer, and also exhibited a higher degree of suppression against Micrococcus flavus ATCC 10240 inoculated into the microbial medium. Addition of NaCl, sugar and citric acid to water significantly reduced the rate of diffusion of nisin in the case of acrylic polymer, while only slight change was observed due to the additive for vinyl acetate-ethylene co-polymer. The simulant type slightly affected the equilibrated migration level of nisin. When the nisin-incorporated coatings were in contact with pasteurized milk and orange juice at 10°C, significant suppression of total aerobic bacteria and yeasts was observed without any noticeable difference between the two types of coatings. Copyright © 2002 John Wiley & Sons, Ltd. [source] Formation and Distribution of Silver Nanoparticles in a Functional Plasma Polymer Matrix and Related Ag+ Release PropertiesPLASMA PROCESSES AND POLYMERS, Issue 7 2010Enrico Körner Abstract Plasma polymer coatings with embedded Ag nanoparticles were deposited in a low pressure RF plasma reactor using an asymmetrical setup with an Ag electrode. The plasma polymer was deposited from a reactive gas/monomer mixture of CO2/C2H4 yielding a functional hydrocarbon matrix. In addition, Ar was simultaneously used to sputter Ag atoms from the Ag electrode, forming nanoparticles within the growing polymer matrix. The influence of the power input, gas ratio and coating thickness on both, the Ag content and the Ag nanoparticle morphology, as well as the distribution in the polymer matrix were investigated. It was found that both increasing the power input and the CO2 ratio result in a higher incorporation of Ag into the matrix. [source] Progress toward a biomimetic leaf: 4,000 h of hydrogen production by coating-stabilized nongrowing photosynthetic Rhodopseudomonas palustrisBIOTECHNOLOGY PROGRESS, Issue 4 2010Jimmy L. Gosse Abstract Intact cells are the most stable form of nature's photosynthetic machinery. Coating-immobilized microbes have the potential to revolutionize the design of photoabsorbers for conversion of sunlight into fuels. Multi-layer adhesive polymer coatings could spatially combine photoreactive bacteria and algae (complementary biological irradiance spectra) creating high surface area, thin, flexible structures optimized for light trapping, and production of hydrogen (H2) from water, lignin, pollutants, or waste organics. We report a model coating system which produced 2.08 ± 0.01 mmol H2 m,2 h,1 for 4,000 h with nongrowing Rhodopseudomonas palustris, a purple nonsulfur photosynthetic bacterium. This adhesive, flexible, nanoporous Rps. palustris latex coating produced 8.24 ± 0.03 mol H2 m,2 in an argon atmosphere when supplied with acetate and light. A simple low-pressure hydrogen production and trapping system was tested using a 100 cm2 coating. Rps. palustris CGA009 was combined in a bilayer coating with a carotenoid-less mutant of Rps. palustris (CrtI,) deficient in peripheral light harvesting (LH2) function. Cryogenic field emission gun scanning electron microscopy (cryo-FEG-SEM) and high-pressure freezing were used to visualize the microstructure of hydrated coatings. A light interaction and reactivity model was evaluated to predict optimal coating thickness for light absorption using the Kubelka-Munk theory (KMT) of reflectance and absorptance. A two-flux model predicted light saturation thickness with good agreement to observed H2 evolution rate. A combined materials and modeling approach could be used for guiding cellular engineering of light trapping and reactivity to enhance overall photosynthetic efficiency per meter square of sunlight incident on photocatalysts. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Ceric Ammonium Nitrate Initiated Grafting of PEG to Plasma Polymers for Cell-Resistant SurfacesPLASMA PROCESSES AND POLYMERS, Issue 2 2008Naomi J. Vickers Abstract The development of a facile method with general applicability and mild reaction conditions for grafting PEG onto surfaces to reduce bio-adhesion is described. The approach taken was to use CAN to graft PEG to plasma polymers coatings selected to give a high concentration of alcohol groups. The study showed that grafting required functional groups on surfaces, a minimum concentration of CAN initiator (0.05 M) and was time and initiator concentration dependent. Adhesion of fibroblasts and endothelial cells was reduced to negligible levels compared to the adhesion to tissue culture polystyrene and untreated plasma polymers of allyl alcohol following CAN induced PEG grafting. [source] | |||||||||||||||||||||||||