Wellert Stefan, Hertle Yvonne, Richter Marcel, Medebach Martin, Magerl David, Wang Weinan, Demé Bruno, Radulescu Aurel, Müller-Buschbaum Peter, Hellweg Thomas, von Klitzing Regine
Stranski Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17 Juni 124, 10623 Berlin, Germany.
Langmuir. 2014 Jun 24;30(24):7168-76. doi: 10.1021/la500390j. Epub 2014 Jun 12.
Microgel particles of cross-linked poly(NIPAM-co-acrylic acid) with different acrylic acid contents are investigated in solution and in the adsorbed state. As a substrate, silicon with a poly(allylamine hydrochloride) (PAH) coating is used. The temperature dependence of the deswelling of the microgel particles was probed with atomic force microscopy (AFM). The inner structure of the adsorbed microgel particles was detected with grazing incidence small angle neutron scattering (GISANS). Small angle neutron scattering (SANS) on corresponding microgel suspensions was performed for comparison. Whereas the correlation length of the polymer network shows a divergence in the bulk samples, in the adsorbed microgel particles it remains unchanged over the entire temperature range. In addition, GISANS indicates changes in the particles along the surface normal. This suggests that the presence of a solid surface suppresses the divergence of internal fluctuations in the adsorbed microgels close to the volume phase transition.
研究了不同丙烯酸含量的交联聚（N-异丙基丙烯酰胺-共-丙烯酸）微凝胶颗粒在溶液中和吸附状态下的情况。以涂有聚（烯丙胺盐酸盐）（PAH）的硅作为基底。用原子力显微镜（AFM）探测微凝胶颗粒去溶胀的温度依赖性。用掠入射小角中子散射（GISANS）检测吸附的微凝胶颗粒的内部结构。对相应的微凝胶悬浮液进行小角中子散射（SANS）以作比较。虽然聚合物网络的相关长度在本体样品中显示出发散，但在吸附的微凝胶颗粒中，它在整个温度范围内保持不变。此外，GISANS表明颗粒沿表面法线方向存在变化。这表明固体表面的存在抑制了吸附微凝胶中接近体积相变时内部涨落的发散。
