Transparent, Superflexible Doubly Cross-linked Polyvinylpolymethylsiloxane Aerogels and Xerogels for Superinsulation

摘要

Superflexible polyvinylpolymethylsiloxane (CH2CH(Si(CH3)O2/2))n aerogels have been facilely prepared from a single precursor vinylmethyldimethoxysilane or vinylmethyldiethoxysilane without organic cross-linkers. It is based on a consecutive process involving radical polymerization and hydrolytic polycondensation, followed by ultralow-cost, highly scalable ambient pressure drying directly from alcohol as a drying medium without any modification and additional solvent exchange. The resulting aerogels and xerogels show a homogeneous, tunable, highly porous, doubly crosslinked nanostructure with the elastic polymethylsiloxane network crosslinked with flexible hydrocarbon chains. An outstanding combination of ultralow cost, high scalability, uniform pore size, high surface area, high transparency, high hydrophobicity, excellent machinability, superflexibility in compression, superflexibility in bending, and superinsulating properties has been achieved in a single aerogel or xerogel. This study demonstrates a significant progress in low-density porous materials and makes the practical applications of transparent flexible aerogel-based superinsulators realistic.