Facile synthesis of flexible and hydrophobic polymethylsilsesquioxane based silica aerogel via the co-precursor method and ambient pressure drying technique

The fragility, hydrophilicity and high cost fabrication of aerogels have limited their applications in industrial and civilian fields. Herein, we have described a method for preparing a novel flexible and hydrophobic silica aerogel by using the co-precursors method via ambient pressure drying technique. The optimal MTMS volume percentage is determined at 60%. The resulting aerogel obtains agglomerated particles with diameters at ~20–30 nm and mesopores at several tens of nanometers. The Si-C-H bond ratio maintains at 13. 36% after heat treatment at 300 °C, which results in the high water contact angle of 153.9°. Moreover, the 300 °C heat treated aerogel has a much more homogeneous microstructure with its BET specific surface area as large as 895.5 m²/g. The oxidation peak of -CH₃ groups is observed at 492 °C. The aerogel exhibits an excellent flexibility under 50 compression cycles, as well as a superior thermal insulation property.