Convenience and Rapid Preparation of Ambient Pressure-Dried Aerogels

Abstract

In the sol-gel stage, dimethyldiethoxysilane was introduced to hydrophobically modify the aerogel by the co-precursor method, and the content of the alkali catalyst was adjusted to coarsen the skeleton structure. Aerogels with a unique three-dimensional network structure were successfully prepared by ambient pressure drying. When the dilute ammonia content is 15 ml, DDS/SiO2 aerogel has the lowest density (0.102 g/cm3), the highest porosity (95.3%) and the lowest thermal conductivity (0.03203 Wm-1K-1). This method is different from the tedious steps of preparing silica aerogels by atmospheric pressure drying. The fastest preparation process only takes 15 hours. It provides ideas for the preparation of aerogels with low cost and high efficiency, and has great application prospects in the broad commercial production field of aerogels. And meanwhile, DDS/SiO2 aerogel has superhydrophobicity with a contact angle of more than 150 °. The prepared DDS/SiO2 aerogel can be used in harsh and humid environments.

Keywords: Atmospheric pressure drying, aerogel, Hydrophobic modification, Porous structure, Skeleton strength