Super-elasticity and deformation mechanism of three-dimensional pillared graphene network structures

Covalently bonded graphene/single-walled carbon nanotube (SWCNT) hybrid material can extend the excellent properties of graphene and SWCNT to three dimensions. We perform molecular dynamics simulations to investigate the mechanical properties of pillared vertically aligned carbon nanotube-graphene (VACNT-graphene) structure under uniaxial tensile and compressive loadings. The simulation results demonstrate that VACNT-graphene structures exhibit excellent elasticity with considerable elastic compressive/tensile strain limit. The early small deformation is dominated by the bending of graphene layers. Under larger elastic strain, graphene layers will form a corrugated pattern and shrink laterally in both the compression and tension processes. In the compression process, the failure mode of VACNT-graphene structure with small pillar distance is the bond breaking and reforming on the ridges of corrugated-shaped graphene and junction areas, while the failure mode of the structure with large pillar distance is the structural buckling. The elastic compressive strain limit exhibits a local maxima at the critical point between the two failure modes. In the tensile process, the failure is due to structural damage and elasticity increases with the pillar distance increasing. The essential tendency in our simulated VACNT-graphene structure might be significant to the further design and application of CNT-graphene hybrid materials.

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