Densification of acid-catalyzed silica xerogels

Article abstract of DOI:10.1007/BF00360723

Wet acid-catalyzed gels prepared by hydrolysis and condensation of tetramethylorthosilicate (TMOS) can be dried without the occurrence of fractures or cracks when drying conditions are appropriate. Furthermore, the resultant dried gel monoliths can be converted to silica glass on heating to 1100 °C and holding there for 30 min when the composition of the starting solution is appropriate. The xerogel to glass transformation was followed by scanning electron microscopy (SEM), small-angle X-ray scattering, Brunauer-Emmett-Teller (BET) measurements, low-frequency Raman scattering and dilatometric measurements and reveals that the densification process is different from the one described for base-catalyzed xerogels.