Graphene coating- and electro-wetting strategy for micro/nanostructured surfaces

•The wettability of different grooved surfaces is thoroughly investigated.•The graphene coating and electric field can reduce the free energy barrier of wetting transition.•The primary cause of electric field-enhanced wetting is the alignment of water molecules at the interface. In this work, an effective strategy for nanostructured surface wetting based on the external electric field and the graphene coating is proposed in the context of classic molecular dynamics models. For water-resistant nanogrooves, the wetting transition from the Cassie-Baxter (CB) to the Wenzel (WZ) state is generated in the presence of the monolayer graphene coating under an external electric field of about 0.07 V/Å. Moreover, due to the funnel-like structure, the electrowetting of double-trapezoid nanogrooves can be enhanced relative to that of single-trapezoid nanogrooves. Besides, the calculated profiles of dipole moments and 1D free-energy landscapes exhibit a remarkable reduction in the free energy barrier required for the wetting transition assisted by the electric field and the graphene coating. This study provides atomistic insights into the wetting behavior of nanostructures under a variety of conditions, which is of great help to manufacture micro/nanostructured surfaces.