Characterization of Micro-Morphology and Wettability of Lotus Leaf, Waterlily Leaf and Biomimetic ZnO Surface

The aim of this paper is to characterize the microrelief and wettability of lotus leaf, waterlily leaf and biomimic ZnO surface with potential engineering applications. The characterizations of morphologies reveal that the top surface of lotus leaf is textured with 4 mu m - 10 mu m size protrusions and 70 nm - 100 nm nanorods, while the top surface of waterlily leaf is textured with wrinkle and decorated with concave coin-shaped geometric structure. The wettabilities of water and oil on lotus leaf and waterlily leaf under different surroundings were systematically researched. It is indeed interesting that the leaves of the two typical plants both living in the aquatic habitats possess opposite wettabilities: superhydrophobicity for top surface of lotus leaf (156 degrees) while quasi-superhydrophilicity for top surface of waterlily leaf (15 degrees). We have succeeded in fabricating the superhydrophobic ZnO nanorods semiconductor material (151 degrees) employing a simple method inspired by the detailed structures and chemical composition of lotus leaf.