Graphene/h-BN hybrid van der Waals structures with high strength and flexibility: A nanoindentation investigation

Two-dimensional nanomaterials, such as graphene and h-BN have been widely used as reinforcing fillers for polymer-based impact protection materials, phase change materials (PCM) or thermal interface materials (TIM) due to its exceptional high mechanical strength and high thermal conductivity. But the mechanical properties of graphene/h-BN (GBN) van der Waals (vdW) heterostructures remain largely unexplored. Herein we carry out intensive nanoindentation tests on GBN by using molecular dynamics simulations as well as finite element analysis to investigate its mechanical properties, fracture mechanisms as well as the effective manipulation techniques for force and deformation. Compared with its homogeneous counterparts (pure graphene or pure h-BN), the heterogeneous GBN possess excellent performance in resisting bending deformation in terms of the indentation load and depth. The size-dependent performance of GBN can be effectively manipulated by hydrogenation in the middle graphene and layer number, except the composition diffusion interface. This comprehensive study confirms that the high strength and high flexibility of GBN endow it with great potential in the applications of impact protection and thermal management in PCM and TIM.