Fabrication of Functionalized Copper Compound Hierarchical Structure with Bionic Superhydrophobic Properties

Hierarchical structure of flower-like CuO standing on Cu(OH)2 nanorod arrays, similar to that of a lotus leaf, was directly fabricated on the surface of copper foils by a simple one-step solution-immersion process. It was found that the diameter of the nanorods ranges from 100 to 500 nm, and the length of the rods is about tens of micrometers. Synchronously, flower-like CuO with a diameter of about 3−5 μm was also deposited from the bulk solution during the growth of nanorod arrays. The wettability of the surface with hierarchical structure was changed from surperhydrophilicity to superhydrophobicity by chemical modification with stearic acid (STA) or 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDES). The static contact angles (CAs) for water on both of the modified surfaces were larger than 160°, which was closely related to the chemical modification and hierarchical structure. Compared with the STA-modified surface, the PDES-modified surface had a lower CA hysteresis (CAH) and adhesion for water droplets. Furthermore, the surfaces retained good superhydrophobic stability in long-term storage as well, which should be critical to the application of Cu materials in engineering.