Abstract

Structural analysis in the range of characteristic sizes from 1 nm to ~1.5 µm was performed for SiO₂–TiO₂ aerogels prepared in supercritical CO₂, isopropanol, hexafluoroisopropanol, or methyl-tert-butyl ether using small-angle X-ray scattering and neutron scattering complementary methods. A two-level model that accounts for scattering by individual inhomogeneities and their aggregates, which have fractal properties, satisfactorily describes the aerogel structures over the entire range of scales. It is shown for the first time that the titania concentration is the key factor in the small-angle neutron and X-ray scattering by SiO₂–TiO₂ aerogels. The phase composition of an aerogel does not significantly affect the aerogel structure in the range of scales from 1 nm to ~1.5 µm, as probed by small-angle X-ray and neutron scattering.

中文翻译：

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SiO2-TiO2 二元气凝胶：小角度散射研究

摘要

对在超临界 CO ₂、异丙醇、六氟异丙醇或甲基叔丁基醚中制备的SiO ₂ -TiO ₂气凝胶进行了从 1 nm 到 ~1.5 µm 的特征尺寸范围内的结构分析，使用小角 X 射线散射和中子散射互补方法。一个两级模型解释了个体不均匀性及其具有分形特性的聚集体的散射，令人满意地描述了整个尺度范围内的气凝胶结构。首次表明二氧化钛浓度是SiO ₂ –TiO ₂小角中子和X射线散射的关键因素气凝胶。通过小角度 X 射线和中子散射探测，气凝胶的相组成不会显着影响 1 nm 到 ~1.5 µm 范围内的气凝胶结构。