Two-step growth of superhydrophobic ZnO nanorod array films

Well-aligned ZnO nanorod array films (ZnO-NAFs) were coatedon common glass substrate by two-step method. A thin buffer layer of ZnO seeds were first deposited via RF magnetron sputtering,the ZnO-NAFS were then grown in a simple aqueous solution. We report a surface-modification induced hydrophilicity to superhydrophobicity transiton on ZnO-NAFs. The sample was characterized by scanning electron microscopy (SEM). The surfaces of ZnO-NAFs was superhydrophobic with a three-phase contact angle of 151°±0.5°, while the sliding angle is 7°. The superhydrophobicity of ZnO-NAFs was validated by Cassie's model.