The structural and mechanical properties of graphene aerogels based on Schwarz-surface-like graphene models

摘要

Discontinuous 3D graphene structures in graphene aerogels endow them extremely low density and excellent compression recovery. These types of discontinuous 3D graphene structure can be theoretically considered as continuous 3D curved graphene structures with large defects like holes with free edges. In order to investigate the structural and mechanical properties of graphene aerogels, we use phase-field-crystal method in finite element method scheme and molecular dynamics simulations to build a group of discontinuous curved graphene models based on a group of Schwarz-surface-like graphene models which possess continuous curved graphene structures. The structural and mechanical properties of both the continuous and discontinuous curved graphene models are investigated. It shows that the discontinuous curved graphene structures possess much lower Young's modulus and worse damage-free compression recovery than continuous curved graphene models. This reveals that the mechanical properties of graphene aerogels can be significantly improved by enhancing the structural continuity. Moreover, a shear strengthening mechanism is found in part of the continuous curved graphene models. Considerable shear stresses in these models enhance the stiffness by sacrificing the yielding strength a little. It indicates that the introduction of shear strengthening mechanism by structure design can further tune the mechanical properties of graphene aerogels. (c) 2018 Elsevier Ltd. All rights reserved.