High specific surface area hybrid silica aerogel containing POSS

Abstract

A UV-initiated thiol-ene click reaction was utilized to synthesize the multifunctional POSS-based silane coupling agent (OTS) from Octavinyl silsesquioxane (OVS) and 3-mercaptopropyltrimethoxysilane (MPTMS). Through supercritical drying, a series of hybrid aerogels with different OTS contents were successfully prepared by two-step sol-gel method using OTS and tetraethyl orthosilicate (TEOS) as the main precursors. In the formation of hybrid aerogels, the nucleation of OTS with flexible side chains had a significant effect on the size of the secondary particles and pore structure of aerogels. Compared with silica aerogels prepared from single TEOS, the hybrid aerogels had more uniform mesoporous and higher specific surface area. The result revealed all hybrid aerogels owned mesoporous structure (3–4 nm), low thermal conductivity (0.038–0.044 W m −1 K −1 ) and remarkable high specific surface area (945–1283 m 2 g −1 ). The outstanding properties made hybrid aerogels promising as adsorbents or thermal insulation materials. • A multifunctional POSS-based silane coupling agent (OTS) was successfully synthesized. • The addition of OTS with flexible side chains as nucleating agents had a significant effect on the pore structure of aerogels. • A series of hybrid silica aerogels with high specific surface area were successfully prepared, which the maximum reached to 1283 m 2 g −1 .