Mechanical properties of graphene oxide: A molecular dynamics study

In this paper, the mechanical properties of graphene oxide are obtained using the molecular dynamics analysis, including the ultimate stress, Young modulus, shear modulus and elastic constants, and the results are compared with those of pristine graphene. It is observed that the increase of oxide agents (-O) and (-OH) leads to the increase of C-C bond length at each hexagonal lattice and as a result, alter the mechanical properties of the graphene sheet. It is shown that the elasticity modulus and ultimate tensile strength of graphene oxides (-O) and (-OH) decrease significantly causing the failure behavior of graphene sheet changes from the brittle to ductile. The results of shear loading tests illustrate that the increase of oxide agents (-O/-OH) results in the decrease of ultimate shear stress and shear module of the graphene sheet. It is shown that the increase of oxide agents in the graphene sheet leads to decrease of the elastic constants, in which the reduction of elastic properties in the armchair direction is more significant than the zigzag direction. Moreover, the graphene sheet with oxide agents (-O) and (-O/-OH) presents an anisotropic behavior.