Convenient and rapid preparation of aerogels dried at ambient pressure

Dimethyldiethoxysilane (DDS) was introduced as a coprecursor to hydrophobically modify aerogels during the sol-gel stage. By adjusting the content of alkali catalyst (dilute ammonia), the skeletal structure was coarsened, leading to the successful preparation of aerogels with excellent three-dimensional network structures via ambient pressure drying. The DDS/SiO2 aerogel formed with a dilute ammonia content of 15 ml exhibited remarkable properties, including the lowest density (0.102 g/cm3), highest porosity (95.3 %), and lowest thermal conductivity (0.03203 W·m − 1·K − 1). This simplified method greatly reduces the intricate steps involved in the conventional ambient pressure drying process for the preparation of silica aerogels. The fastest preparation process in this study lasted only 15 h, providing an efficient and cost-effective approach for producing aerogels. Furthermore, the DDS/SiO2 aerogel demonstrated superhydrophobicity with a contact angle exceeding 150° Due to this characteristic, the prepared DDS/SiO2 aerogel is highly suitable for use in harsh and humid environments.