Tension dynamics of graphene oxide and peculiar change of yield strain

Abstract

Tension dynamics is key to graphene oxide (GO) when composited in flexible materials, and there is still lack of some dynamic pictures to show how it is affected by oxidation level. In this paper, uniaxial tension of GO with different oxygen-containing functional groups densities (R) are simulated by molecular dynamics. It is indicated that the elastic modulus and ultimate stress both decrease with increasing R, especially when R < 30%. The yield strain along AC-orientation falls after rises because of the R-depended fractural mechanisms: when R is small, cracks initiate from the distorted carbon bonds connecting to oxygen-containing groups and propagate along the ZZ-orientation, or else, cracks start from the point defects and expands by consolidating point defects; when loaded along the ZZ-orientation, however, fractures are edge dominated. Our research suggests that introducing oxygen-containing groups would be a feasible strategy to improve the deformability of graphene oxide.