Superhydrophobic surface decorated with vertical ZnO nanorods modified by stearic acid

Static and dynamic wettability of the ZnO nanorod surface prepared by a facile and inexpensive route is reported. The wettability of the ZnO surface was controlled and tuned by post hydrophobization using different stearic acid concentrations. The surface of the ZnO nanorods modified with 8 mM stearic acid showed a static water contact angle of 152 and sliding angle of 9, which indicates superhydrophobicity. This suggests that the combination of the rough structures achieved by the ZnO nanorods and low surface energy provided by stearic acid modification results in superhydrophobicity and a very low sliding angle. The crystal structure, surface chemical elements, surface morphology, surface roughness, and static and dynamic water contact angles of the ZnO coatings were studied in detail. Further, the surface properties were assessed by calculating the surface free energies and work of adhesion for unmodified and stearic-acid-modified ZnO nanostructure surfaces. These coatings can find potential industrial applications in the electronic industry. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.