Wettability of zinc oxide surfaces with controllable structures.

Zinc oxide (ZnO) surfaces with controllable structures (i.e, microstructure, nanostructure, and micronanobinary structure) have been created by controlling pH at < 4 or > 10.5 in the Zn(gray) + H2O2 reaction. The resulting surface shows superhydrophobicity. It is found that the water contact angle (CA) of the surface with micronanobinary structure is greater than that of nanostructure and that of nanostructure is greater than that of the microstructure. Theoretical analysis is completely in agreement with the experimental results.