Garnweitner Georg, Smarsly Bernd, Assink Roger, Ruland Wilhelm, Bond Evelyn, Brinker C Jeffrey
Center for Micro-Engineered Materials, University of New Mexico, Albuquerque, New Mexico 87131, USA.
J Am Chem Soc. 2003 May 14;125(19):5626-7. doi: 10.1021/ja0342648.
Thermoresponsive nanocomposite thin films composed of alternating layers of silica and polymerized N-isopropylacrylamide (NIPAM) or NIPAM plus dodecyl methacrylate (DM) hydrogels were prepared by surfactant-directed evaporation-induced self-assembly (EISA). During EISA, the organic monomers partition within the hydrophobic domains of a lamellar mesophase. In-situ polymerization via a free radical process results in a 1-2 nm thick hydrogel phase sandwiched between layers of silica oriented parallel to the substrate surface. The thermoresponsiveness of PNIPAM is preserved in this confined environment, and the polymeric layers reversibly swell and deswell by a factor of 2 in water upon temperature changes around the transition temperature of PNIPAM (32 degrees C). The composition, mesostructure, and environmental response were studied by detailed NMR, TGA, and SAXS analyses.
通过表面活性剂导向的蒸发诱导自组装（EISA）制备了由二氧化硅和聚合的N-异丙基丙烯酰胺（NIPAM）或NIPAM加甲基丙烯酸十二酯（DM）水凝胶交替层组成的热响应纳米复合薄膜。在EISA过程中，有机单体在层状中间相的疏水区域内分配。通过自由基过程进行原位聚合，形成了夹在平行于基底表面取向的二氧化硅层之间的1-2纳米厚的水凝胶相。PNIPAM的热响应性在这种受限环境中得以保留，并且聚合物层在PNIPAM转变温度（32℃）附近温度变化时，在水中可逆地膨胀和收缩，膨胀和收缩倍数为2。通过详细的核磁共振（NMR）、热重分析（TGA）和小角X射线散射（SAXS）分析研究了其组成、介观结构和环境响应。
