Performance regulation of silica aerogel powder synthesized by a two-step Sol-gel process with a fast ambient pressure drying route

Abstract

This paper proposed a timesaving route for preparing silica aerogel powder with TEOS as a precursor. Thermal insulating super hydrophobic silica aerogel powder was synthesized by combining two-step Sol-gel reaction with a fast ambient pressure drying process. Silica Sol-gel was formed after catalytic reaction by oxalic acid and NH4OH, and then turned to be hydrophobic aerogel through further surface modification (only three hours with no solvent exchange process) and drying process. By optimizing every tiny trace of synthetic component, the obtained silica aerogel powder exhibits excellent properties, such as low apparent density (0.212 g/cm3) and thermal conductivity (0.053 W/mK), as well as high BET surface area (769.86 m2/g) and water contact angle (149.0 °). This work presents a timesaving method for synthesizing thermal insulating hydrophobic silica aerogel powder.