Electron diffraction analysis of the structure of SiO2 gel-film

Abstract

The structure of self-supported SiO2 gel-films prepared from acid and basic TEOS solutions is analysed by high energy transmission electron diffraction method. The reduced radial distribution function (RDF) curves show that all the films are already well dense despite the low drying temperature (≤50°C) and short drying time (≤30 s). The Si-O bond length of the gel-films prepared from highly acid and basic solutions is about 1.58 Å; it is smaller than that of bulk vitreous silica (1.61 Å) but similar to that of 80 Å thick evaporated a-SiO2 film.