Water-Mediated Attractive Interaction between Negatively Charged GO Nanosheets at the Air-Water Interface

Understanding the interaction of ionized two-dimensional (2D) graphene oxide (GO) nanosheets at the air-water interface can improve the self-assembly framework of GO sheets. Herein, the potential of mean force (PMF) was simulated to study the edge-to-edge interacting mode between two deprotonated GO nanosheets at the air-water interface. The PMF profile displays a unique phenomenon that ionized GO nanosheets with the same negative charge can attract each other at the interface, which is obviously in contrast with the repulsive interaction in the bulk phase. The attractive interaction between the negatively charged GOs at the interfaces can be attributed to an enhanced solvation interacting force arising from the bridge water structure shared by the two single-layer ionized GO sheets. More specifically, the novel interfacial interaction is highly correlated with the charged nature of GO sheets and their special parallel packing arrangement at the interface. Our simulation result, for the first time, provides new physical chemistry insights into the interface-mediated solvation force between charged 2D nanoparticles.