Synthesis of highly flexible silica aerogels by photoacids generation

Highly flexible silica aerogels were fabricated by using 2-(3-(triethoxysilyl)propylcarbamoyloxy) ethyl acrylate (TESEA), methyltriethoxysilane (MTES), and polydimethylsiloxane (PDMS) as co-precursors through photopolymerization and sol–gel process, then followed by ambient pressure drying. Attributing to photolysis of the photoacids generators, the radical and Brönsted acid (HSbF 6 ) were generated simultaneously under irradiation. The radical initiated the photopolymerization of acrylate which induced the gelation and fixed the shape of the gel quickly, the acid allowed the sol–gel process occurring gradually. Due to the enhancement of the polymer, the strength of aerogels was improved. The aerogels had low density (~ 0.098 g/cm 3 ), high porosity (~ 94.8%), high flexibility and high elastic recovery. Moreover, the silica aerogels have hydrophobic and oleophilic properties, which endows them with an ability of oil water separation.