Flexible and superhydrophobic silicon-based hybrid aerogels via spring-back effect for oil-water separation and thermal insulation

Flexible aerogels with low density and high porosity were successfully prepared by sol-gel and atmospheric pressure drying (APD) using methyltrimethoxysilane (MTES) and sodium silicate as co-precursors and hydroxylterminated polydimethylsiloxane (PDMS) as cross-linking agent. The effects of the aerogel framework morphology on mechanical properties, thermal insulation performance, and adsorption capacity was investigated. The volume of PDMS introduced is precisely controlled to adjust the skeletal structure of the aerogel and to enhance structural integrity by utilizing the rebound effect during the drying process. Increasing PDMS content altered the aerogel skeleton from a fragmented structure to a coarsened, interconnected 3D with large particles. This optimized coarsened structure yielded an aerogel with a low density of 0.096 g cm-3, high porosity of 91.1 %, low thermal conductivity of 0.027 W m-1 K-1, and contact angle of 153.1 degrees. It is capable of being compressed to 40 % of the original height for 9 cycles without structural damage. Additionally, these aerogels demonstrate exceptional adsorption capacities for volatile organic compounds and petroleum derivatives, enabling dual-functionality in environmental remediation and precision thermal management systems operating under demanding industrial conditions.