Manipulating the elasticity of chemically modified graphene aerogel through water surface plasticization

Self-assembled chemically modified graphene (CMG) aerogels with high compressive elasticity are important materials because of their unique properties and broad applications, but there is a lack of guiding principles for the design of elastic CMG aerogels. In this work, we provide new insights into the elasticity of chemical modified graphene aerogels. We demonstrate that the self-assembled CMG aerogels have intrinsic compressive elasticity, and report a reversible transition of CMG aerogels from elasticity to plasticity caused by water adsorption. Experimental data and molecular dynamics simulations show that water molecules on the surface of the ultrathin CMG cell walls in the aerogel form a hydrogen bond network, which hinders the shape recovery of the bent cell walls and plasticize the aerogel. A general method is then developed to enhance the elasticity of CMG aerogel by reducing its surface hydrophilicity with thermal treatment. The method efficiently imparts good elasticity to aerogels prepared by conventional hydrothermal methods. This work clarifies the important influence of water surface plasticization on the elasticity of CMG aerogels, and provides principles for the design of highly elastic aerogels based on low dimensional nanomaterials. (c) 2021 Elsevier Ltd. All rights reserved.