Wettability of Graphene-Coated Surface: Free Energy Investigations Using Molecular Dynamics Simulation

Abstract

A clear understanding of the wettability of graphene and graphene-coated surfaces is of critical importance for the practical applications of graphene. The present study provides microscopic and thermodynamic perspectives into the wettability of graphene-coated surfaces by molecular dynamics simulations along with free energy calculations utilizing the umbrella sampling. The water droplet adhesion process on graphene-coated surface was characterized by the change in surface area, mean force, and free energy of the droplet. The thermodynamic landscape analysis reveals that the different contributions to the free energies from different underlying substrates induce different entropic resistances from graphene, which leads to the similarity in wettability for graphene-coated silicon and hydroxylated silicon dioxide substrates.