Effect of oxygen configurations on the mechanical properties of graphene oxide

Understanding the mechanical properties of graphene oxide (GO) is the primary challenge for applications in materials engineering. The degree of oxidation and concentration of epoxide functional groups have been the main focus of previous mechanochemical studies. This work uses the reactive molecular dynamic simulations to reveal that the mechanical behavior of GO is strongly dependent on the epoxide configuration as well as its distribution. In this study, three main epoxide configurations - including top, bridge, and reside groups - decorate monolayer GO sheets with linear and random distributions. The distortion associated with epoxide groups creates diamond-like structures controlling the mechanical properties. Moreover, the orientation of those epoxide functional groups with applied loads has a dramatic impact on the mechanical response of GO. The effect of external electric fields on the mechanical properties of GO is another objective of this study. Findings exhibit that the electric field enhances the tensile toughness. This study demonstrates new aspects of GO as a functional material with potentials to control the mechanical properties through chemical compositions as well as external electric fields.