Dynamic Wetting of Nanodroplets on Smooth and Patterned Graphene-Coated Surface

Wettability of graphene-coated surface has gained significant attention due to the practical applications of graphene. In terms of static contact angle, the wettability of graphene-coated surfaces has been widely investigated by experiments, simulations, and theories in recent years. However, the studies of dynamic wetting on graphene-coated surfaces are limited. In the present study, molecular dynamics simulation is performed to understand the dynamic wetting of water nanodroplet on graphene-coated surfaces with different underlying substrates, copper, and graphite, from a nanoscopic point of view. The results show that the spreading on smooth graphene-coated surfaces can be characterized by the final equilibrium radius of droplet and inertial time constant. The dynamics of spreading of water nanodroplet on graphene-coated surface with patterned nanostructures on graphene is also carried out. Unlike the smooth graphene-coated surfaces, dynamic wetting on the patterned graphene-coated surfaces depends on the underlying substrate: the inhibition of wetting by the surface nanostructures is stronger for a hydrophobic underlying substrate than a hydrophilic underlying substrate.