Fabrication of biomimetic lotus leaf film of ZnO by a two-step method of nanoimprint and hydrothermal growth for superhydrophobic applications

In this paper, the biomimetic lotus leaf films of ZnO were fabricated by the two-step method of UV imprint and hydrothermal growth. First, the photoresist micropapillae film was prepared by UV imprint technique from a natural lotus leaf. Then the hydrothermal growth method was used to grow ZnO nanowires (NWs) on the surface of the photoresist micropapillae film and obtained the biomimetic lotus leaf films of ZnO. ZnO NWs with high aspect ratio were obtained by changing the concentrations of growth solution and the assistance of additives. Different methods including SEM?TEM? XRD and XPS were used to characterize the surface structure and chemical properties of the films. Results show that the films have significant micro-nano hierarchical structures, which the ZnO NWs are arranged uniformly. The superhydrophobic and self-cleaning properties of the ZnO films were also investigated, and the water contact angle and sliding angle of the films can respectively reach 156 degrees and 9.6 degrees. Thus, it is a simple and low cost process to fabricate biomimetic lotus leaf films of ZnO with superhydrophobic properties by the two-step method. The prepared ZnO films have potential application prospects in photovoltaic energy, medical, military and other fields.