Corrosion Resistance of ZnO Nanorod Superhydrophobic Coatings with Rose Petal Effect or Lotus Leaf Effect.

Superhydrophobic ZnO nanorods coatings with a strong adhesive force to the surface (rose petal effect) or a low sliding angle (lotus leaf effect) were fabricated on the zinc plate by the hydrothermal plus sol-gel method. The corrosion resistance and durability of the superhydrophobic coatings in 5 wt% NaCl solution were investigated. The coating with loose ZnO nanostructure on ZnO nanorods shows a high adhesive force to water with low corrosion resistance, while the coating with a layer of dense nanotubes on nanorods exhibits a low adhesive to water with a high corrosion resistance due to a layer of trapped air among micro/nanostructures, which can delay the penetration of corrosive media. It can be found that the nanorods coating with lotus leaf effect lost its superhydrophobicity after 5150 s immersion in salt solution and the water repellency model is transformed from Cassie state to Wenzel state.