Highly flexible silica aerogels derived from methyltriethoxysilane and polydimethylsiloxane

Abstract

Highly flexible silica aerogels were synthesized using methyltriethoxysilane (MTES) and polydimethylsiloxane (PDMS) as co-precursors via a two-step acid–base sol–gel method followed by ambient pressure drying. The effects of volume ratio of PDMS to MTES (S) on the flexibility were investigated in detail. It was found that, with the increase of S from 5% to 8.75%, both Young's modulus and the density of obtained aerogels decrease from 0.136 to 0.030 MPa and 0.098 to 0.064 g cm⁻³, respectively. Aerogels produced at S of 8.75% show excellent compressional and recoverable properties with, their maximal recoverable compressive strain being 70%. The unrecovered strains calculated immediately and 12 h after compression to 60% strain twenty times are 10.9% and 3.1%, respectively. The excellent flexibility performance of silica aerogels derived from MTES–PDMS makes them a promising silica aerogel material for special applications.