Friction behaviors of graphene sliding on rough Au substrates and intercalated water layer by molecular dynamics simulations

Superlubricity makes graphene an excellent lubricating material. To further investigate the friction properties of graphene, we established atomic models of graphene sheet sliding on the sinusoidally rough Au surface, the randomly rough Au surface, as well as the water molecule layer intercalated on Au substrate, respectively. Our results show that the friction force increases with roughness of the surface, but in the case of a small roughness, the incommensurability between the graphene and Au substrate surfaces reduces the friction force; when a water molecule layer exists, it separates the friction pairs, which results in lower friction than in the dry environment, and the deformability of water also contributes to the frictional hysteresis behavior during the loading and unloading process.