Multicovalent crosslinked double-network graphene–polyorganosiloxane hybrid aerogels toward efficient thermal insulation and water purification

Abstract

Macroscopic-scale graphene-based aerogels are attractive candidates for thermal insulation and water purification due to their unique properties. However, both the mechanically brittle and single functionality restrain their practical application. Herein, covalently crosslinked double−network graphene-based aerogels were designed and prepared via co−gelation of graphene oxide and organosilanes, followed by freeze-drying and thermal-annealing processes. The multicovalent interactions including hydrolytic copolycondensation, ring opening, and silylation reactions occurred during the co−gelation process. The optimized aerogel exhibits highly elastic performance, which can maintain 93.7% of the maximum stress after 200 compress-release cycles at 50% strain. The graphene−polyorganosiloxane hybrid aerogel also synchronously satisfies hydrophobic property and low thermal conductivity (23 mW m−1 K−1) at room temperature, demonstrating its great potential as a thermal insulator in humid and hot environments. Moreover, the aerogels show excellent absorption capacity (uptake of >200 g g−1) and efficient separation of three-component water/oil/dye mixtures. This work shows that organosilanes are promising crosslinkers for producing highly compressible and multifunctional graphene-based aerogels for thermal management and environmental remediation.