Principles determining the aggregation of graphene oxide in aqueous solutions: The effect of heterogeneous distribution of oxygen-containing groups

Abstract

Molecular dynamics (MD) simulations were conducted to investigate the effects of heterogeneous distribution of oxygen-containing groups on the aggregation modes of graphene oxide (GO) flakes in aqueous solution. The results show that the aggregation of GO flakes can be divided into Brownian motion, adsorption, and adjustment steps, where the adsorption step further can be classified as point-falling-line-squeezing-plane (PFLSP) mode and bridge adsorption of confined water molecules mode. When the aggregation happens at the non-oxidized region, the successful aggregation is always accompanied by the PFLSP mode. In contrast, at the oxidized region, the bridge adsorption of CWMs mode is preferred.