Wettability behavior of nanodroplets on copper surfaces with hierarchical nanostructures

[Display omitted] •The wettability on different surface morphologies was studied and compared through molecular dynamics simulation.•Hierarchical gecko pillars are prone to demonstrate better hydrophobicity than nonhierarchical pillars.•The increase of surface characteristic energy and primary groove width can weaken the advantage of hierarchical structures.•The calculated contact angles are in good agreement with the Cassie-Baxter model values for hierarchical structures. Wetting characteristics of nanodroplets on solid surfaces with nanostructures were investigated through molecular dynamics simulations. The effects of the primary groove width and the surface characteristic energy on the surface wettability with hierarchical structures and nonhierarchical structures were studied. Furthermore, the wettability on different surface morphologies was compared systematically. It is found that hierarchical gecko pillars tend to exhibit better hydrophobicity than nonhierarchical pillars. However, the increase of surface characteristic energy and primary groove width can weaken the advantage of hierarchical structures. Moreover, the contact angles gained from simulation were compared with the theoretical prediction values. It is expected that this study may have potential guiding significance in designing surface hydrophobicity.