Papers by Keyword: Amphiphilic Polymer

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Authors: Xiao Nong Chen, Robert Pelton
Abstract: Polystyrene (PS), polyethylene (PE), polypropylene (PP), glass and stainless steel were exposed to aqueous solutions of a series amphiphilic polymers at room temperature, including N-isopropylacrylamide (NIPAM)-based polymers, polyvinylpyrrolidone (PVP), polypropylene oxide (PPO)-polyethylene oxide (PEO) block copolymers and PEO. Dynamic contact angle measurements of the material surfaces before and after the treatment indicate that only NIPAM-based polymers can adsorb on both hydrophobic and hydrophilic surfaces. The surface morphologies of the materials before and after polymer adsorption were investigated by profilometry. Protein adsorption on the surfaces pre-adsorbed NIPAM-based polymers was investigated by dual polarisation interferometry (DPI) and profilometry using lysozyme as the model protein. The results obtained indicate that NIPAM-based polymers can significantly improve the biofouling resistance of synthetic surfaces.
363
Authors: Tang Wei Wang, Zhong Xiao Li, Hua Sheng Lu, Jia Ling Pu
Abstract: A reversible addition fragmentation chain transfer (RAFT) agent, 2-(dodecylthiocarbonothioylthio)propanoic acid (RAFT-1), was synthesized and characterized. Diacetone acrylamide and poly(ethylene glycol)methyl ether methacrylate were polymerized in the presence of RAFT-1 to give an amphiphilic polymer(RAFT-2). A very stable and narrowly-distributed emulsion was obtained by the micellization of the amphiphilic polymer in water. The self-crosslinking resin system was prepared by adding a crosslinker (adipic dihydrazide) to the prepared emulsion. Upon the evaporation of water of the emulsion, a tough and transparent crosslinked film was prepared, which had good water/solvent resistance and certain adhesiveness.
331
Authors: Sang Ho Cha
Abstract: A novel synthetic approach for gold nanocrystals using triblock copolymer as a polymeric template was described. The triblock copolymer used in this study was poly (ethylene oxide)20-poly (propylene oxide)70-poly (ethylene oxide)20 with hydroxy or thiol end-functional groups. The complexes of HAuCl4 and triblock copolymers were prepared by mixing and drying. After exposed to the sunlight for a few days, the gold nanocrystals, which have different sizes and shapes according to the ripening time, end functional groups, and gold salt concentrations, were obtained. The optical properties of the gold nanocrystals were also discussed.
321
Authors: A. Nopwinyuwong, W. Boonsupthip, Chiravoot Pechyen, P. Suppakul
Abstract: Polydiacetylene (PDA) was used as a colorimetric indicator depended on temperature and time. This paper presents a new time-temperature indicator based on PDA vesicle and amphiphilic polymer. The 10,12-pentacosadiynoic acid (PCDA) was prepared with different concentration of Pluronic F127 which was varied from 0 to 4 % w/v, respectively. After that, there was obtained in different temperature (30-50°C) until clearly color change. This solution could gradually change from blue to red color which it could observe by UV-Vis spectrophotometer. The absorbance in each solution was reported at 640 and 540 nm, respectively, and then calculated by the color response (CR). In addition, the CR increased that directly related with temperature and time, when the concentration of F127 was constant. Also, the CR increased that directly related with temperature and concentration of F127, when time was constant. This method could have potential application as a new time-temperature indicator.
552
Authors: Xiao Nong Chen, Zai Qian Qi, Ya Qin Huang, Robert Pelton, Raja Ghosh
Abstract: N-isopropylacrylamide (NIPAM)-ethylene oxide (EO) copolymer was grafted on filter paper surface to obtain paper-based adsorptive membrane. Protein adsorption on and release from the membrane was evaluated under various conditions using humanized monoclonal antibody as model protein. The results obtained indicated that amphiphilic copolymer modified filter paper could be used as a novel chromatographic membrane for protein separation/purification. Comb-block copolymers of NIPAM with N-vinylpyrrolidone (VP) were prepared through RAFT polymerization and macromonomer techniques. Surface modification of substrates, such as plastics and glass, was carried out by treatment of the substrates in aqueous solution of the amphiphilic comb-block copolymer (adsorptive coating, pre-adsorption). It was found that the adsorbed copolymer layer was stable in aqueous environment even when shear stress was applied. Protein adhesion on the material surfaces before and after the modification was investigated using lysozyme as model protein. The results obtained showed that the adsorptive coating layer on the material surfaces significantly reduced non-specific protein adhesion.
1311
Authors: Sang Ho Cha
Abstract: A novel synthetic approach to ultrathin (< 5 nm) multilayered single crystalline gold nanosheets using amphiphilic comb-like polymer as template was presented. The poly (oxyethylene) containing decyl-tri (oxyethylene) amphiphile as well as the thioether linking group in the side chain was synthesized via polymer analogous reaction. The polymer and the gold precursor, LiAuCl4, were mixed and dried to afford a homogeneous complex. The gold precursors were reduced to gold crystals by photoreduction using long wave UV light (> 350 nm). The gold nanosheets with multilayered structure, where the layer spacing is about 3.6 nm, were obtained after 24 h. The formation of the multilayered nanosheets is due to the layered structure of the gold complex of the polymer and precursor.
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