Graphene heals thy cracks

Abstract

Molecular Dynamics simulations revealed the phenomena of self healing of cracks which were generated in graphene on application of tensile load exceeding its ultimate tensile strength. The phenomenon of self healing was observed when the system was studied at a very slow rate of 0.05 ps. Cracks initiated in the graphene sheet was allowed to propagate till it reached a critical length following which the load was removed and the sheet was relaxed. The study revealed that self healing of cracks took place within a critical crack opening displacement range of 0.3-0.5 nm in absence of any external stimulus. However, the self healing phenomenon was found to be independent of crack length. This self healing phenomenon occurred not only in pristine graphene sheet, but also in presence of pre-existing vacancies. The mechanism of self healing has been explained by detailed bond length/angle distribution analysis.