Synthesis of zinc hydroxyl acetate nanosheet-assembled honeycomb-like and flower-like structures by chemical bath deposition method for the construction of hydrophobic surfaces

Layered zinc hydroxyl acetate (LZHA) nanosheet-assembled honeycomb-like and flower-like structures were synthesized by a chemical bath deposition method using aqueous zinc acetate solution as the bath solution and a porous ZnO coating as the substrate. The morphology of LZHA architectures growing on the surface of the substrate depends on the type of LZHA nucleation. The homogeneous nucleation facilitates the adsorption of crumpled LZHA nanosheets generated in the solution onto the substrate surface, whereas heterogeneous nucleation promotes the formation of flat LZHA nanosheets on the substrate surface. The crumpled and flat LZHA nanosheets serving as the seeds undergo cyclic “growth-division” processes to evolve into LZHA nanosheet-assembled honeycomb-like and flower-like structures, respectively. The hierarchical architecture features of the LZHA honeycombs and flowers can be topologically inherited without any crack and collapse when converted into ZnO by calcination. The LZHA honeycomb-like and Ag nanoparticle modified ZnO flower-like structures were characterized by a scanning electron microscope, field-emission scanning electron microscope, energy dispersive X-ray spectrometer and X-ray diffractometer. The synthesized ZnO honeycomb-like and flower-like structures show excellent hydrophobic properties owning to the appropriate roughness provided by the hierarchical structures. In particular, the surface assembled by ZnO honeycombs derived from their LZHA precursors with deposition time of 4 h shows a higher water contact angle of 162.3°. In addition, the Ag nanoparticle modification on the petals of ZnO flowers results in the formation of multi-scale rough surfaces, and thus increases the water contact angle. The synthesized superhydrophobic surfaces exhibit promising applications in fields such as anti-icing, anti-corrosion and reducing fluidic drag.