A novel fabrication of a superhydrophobic surface with highly similar hierarchical structure of the lotus leaf on a copper sheet

A novel and facile avenue was developed to successfully fabricate a regular hierarchical surface structure on a copper sheet via the combination of polydimethylsiloxane (PDMS) template and chemical etching method in this paper. The as-prepared hierarchical surface structure was comprised of uniform-sized microprotrusions and nanostructures which was similar to the natural lotus leaf. After modified by stearic acid, the surface was covered with a layer of hydrophobic chemical groups and became superhydrophobic. The values of its water contact angle and sliding angle were about 153° and 7°, respectively. Its wettability kept rather stable when it was exposed to humid conditions for 3 months. This study provides a new way to fabricate uniform surface microstructures that are highly similar to natural biological surfaces on metal materials.