Hyperelastic and hydrophobic silica aerogels with enhanced compressive strength by using VTES/MTMS as precursors

A hyperelastic and hydrophobic silica aerogel has been prepared by using Vinyltriethoxysilane (VTES) and Methyltrimethoxysilane (MTMS) as the composite precursor. The effect of the VTES/MTMS molar ratio on the morphology of the VTES/MTMS-based aerogel has been investigated. The VTES/MTMS-based aerogel with a typical nano-porous structure exhibits a high surface area (321 m 2 /g), a low density (0.143 g·cm − 3 ) and low thermal conductivity (0.024 ± 0.003 W·m − 1 ·K − 1 ). The existence of methyl and vinyl groups is beneficial to enhancing the elasticities of aerogels. The MVTES5, with a VTES/MTMS molar ratio of 0.060, could bear a compressive strain of 55% and quickly recover to its original length after the stress is released. It is demonstrated that the partial replacement of the methyl with vinyl groups can greatly enhance the mechanical properties , and the compressive stress is 0.571 MPa. Furthermore, the VTES/MTMS-based aerogel exhibits hydrophobic properties with a contact angle of 146°.