Superhydrophobic surfaces via controlling the morphology of ZnO micro/nano complex structure

ZnO micro/nano complex structure films, including reticulate papillary nodes, petal-like and flake-hole, have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts. The wettability of the above film surfaces was modified with a simple coating of heptadecafluorodecyltrimethoxy-silane in toluene. After modifying, the surface of ZnO film grown at 50 ^\circC was converted from superhydrophilic with a water contact angle lower than 5^\circ to superhydrophobic with a water contact angle of 165^\circ. Additionally, the surface of reticulate papillary nodes ZnO film grown at 100 ^\circC had excellent superhydrophobicity, with a water contact angle of 173^\circ and a sliding angle lower than 2^\circ. Furthermore, the water contact angle on the surface of petal-like and flake-hole ZnO films grown at 150 ^\circC and 200 ^\circC were found to be 140^\circ and 120^\circ, respectively. The wettability for the samples was found to depend strongly on the surface morphology which results from the growth temperature.