Molecular dynamics simulation of the mechanical properties of multilayer graphene oxide nanosheets

Abstract

Multilayer graphene oxide (GO) is an attractive candidate for new applications in nanoelectromechanical materials and structural reinforcement nanocomposites due to its strong mechanical properties. In this study, the mechanical properties and failure mechanism of multilayer GO nanosheets were studied by non-equilibrium molecular dynamics simulation. The simulated Young's modulus, fracture stresses, and fracture strains were found to be consistent with the experimentally measured values. The effects of the surface oxidation content of GO and the stacking layer number on these mechanical properties were investigated. The oxidation content has a larger influence on the mechanical properties compared with the layer number. The failure of multilayer GO nanosheets undergoes a relatively slow cracking process due to the existence of functional groups and the stacking layers. There appears to be different two-dimensional stress distributions on multilayer GO sheets from the outer layer to inner layer. The Young's modulus and the fracture strength of the middle layer are generally larger than those in the outer layer. The fracture of the outside GO sheet begins first, and then the failure of the inner GO sheet occurs with a delayering process. The simulation result is expected to improve understanding of the mechanical behavior of multilayer GO nanosheets.