Wetting of Graphene Oxide: A Molecular Dynamics Study

ABSTRACT: We characterize the wetting properties of graphene oxide by performing classical molecular dynamics simulations. With oxygen-containing functional groups on the basal plane, graphene becomes hydrophilic and the water contact angle decreases with their concentration, c. The concentration dependence displays a transition at c ≈ 11 % as defined by the interacting range of hydrogen bonds with oxidized groups and water. Patterns of the oxidized region and the morphological corrugation of the sheet strongly influence the spreading of water droplets with their lateral spans defined by corresponding geometrical parameters and thus can be used to control their behavior on the surface. These results are discussed with respect to relevant applications in graphene oxide-derived functional materials and offer a fundamental understanding of their wetting and flow phenomena. Graphene has attracted much interest recently not only because of its outstanding intrinsic properties but also because of the broad spectrum of materials derived from it through chemica