Preparation and synthesis mechanism of highly efficient thermal insulation SiO2 aerogels

Silica (SiO 2 ) aerogels have excellent physical and thermal properties with high-performance and broad application prospects. In order to obtain SiO 2 aerogels with high thermal insulation performance and explore key process parameters of their preparation, SiO 2 aerogels were prepared via combining sol–gel and freeze-drying processes using tetraethyl orthosilicate (TEOS) as the precursor. Effects of the pH value and the content of deionized water (DIW) on the microstructures and thermal properties of the SiO 2 aerogel were systematically investigated. Results showed that when the pH was 8.0 and the molar ratio of TEOS to DIW was 1:7, the SiO 2 aerogel had the best structure and the lowest thermal conductivity, exhibiting the best thermal insulation effect. In addition, the synthesis mechanism of such sol–gel freeze-dried SiO 2 aerogels was analyzed in depth, and the structural evolution process was also described. This study lays a theoretical foundation for the controllable preparation and process design of SiO 2 aerogels in the future, and has certain guiding significance for promoting their application in the field of efficient thermal insulation.