Molecular dynamics based simulations to study failure morphology of hydroxyl and epoxide functionalised graphene

Abstract

In this article, molecular dynamics based simulations were performed to study the effects of functional groups such as hydroxyl and epoxide on the mechanical strength and failure morphology of graphene oxide. Reactive force field potential was used to capture the interatomic interactions between carbon, oxygen and hydrogen atoms. In contrast to previous observations, atomistic simulations predicted a transition in the failure morphology of hydroxyl functionalised graphene from brittle to ductile as a function of its spatial distribution on graphene. This transition in failure morphology from brittle to ductile was gradual in nature and was observed at lower percentage coverage of graphene in the range of 25–50%. Failure morphologies depict that hydroxyl groups tend to boost the ductility through chains and elongated rings formation at lower percentage coverage. Also, the electrostatic charge redistribution and epoxide to ether transformation were found to be the decisive mechanisms behind the ductile response shown by hydroxyl and epoxide groups, respectively.