Physical Chemistry Department, University of Giessen, 35392 Giessen, Germany.
Langmuir. 2010 May 4;26(9):6583-92. doi: 10.1021/la903934r.
Modified periodically ordered mesoporous organosilica materials were prepared starting from a recently introduced type of sol-gel precursor, containing both organic moieties and hydrolyzable Si-OR groups. In order to thoroughly characterize the mesoporosity and its accessibility, different probe gases were used in conventional gas adsorption experiments. Furthermore, in situ small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) were applied to study the mesoporosity and the sorption processes, taking advantage of scattering contrast matching conditions. Thereby, the materials were characterized not only by different probe molecules but also at different temperatures (nitrogen at 77 K, dibromomethane at 290 K and perfluoropentane at 276 K). The comparison between the standard and in situ SAXS/SANS adsorption experiments revealed valuable information about the porosity and microstructure of the materials. It is demonstrated that the organic moieties are homogeneously distributed; that is, they do not phase-separate from silica on the nanometer scale.
周期性有序介孔有机硅材料是由一种新型的溶胶-凝胶前体制备而成的，该前体中含有有机部分和可水解的 Si-OR 基团。为了彻底表征介孔及其可及性，在常规气体吸附实验中使用了不同的探针气体。此外，还应用原位小角 X 射线散射（SAXS）和小角中子散射（SANS）来研究介孔和吸附过程，利用散射对比度匹配条件。因此，不仅可以用不同的探针分子，而且可以在不同的温度下（77 K 下的氮气、290 K 下的二溴甲烷和 276 K 下的全氟戊烷）对材料进行表征。标准和原位 SAXS/SANS 吸附实验的比较揭示了有关材料孔隙率和微观结构的有价值的信息。结果表明，有机部分均匀分布；也就是说，它们不会在纳米尺度上与二氧化硅相分离。
