Facile preparation of petaliform-like superhydrophobic meshes via moisture etching for oil-water separation

Abstract Developing a facile strategy for high-efficiency mixture separating is highly necessary, especially for the purification of oily wastewater and the refinement of organic solvents. In this work, robust superhydrophobic meshes (Cu@E-Zn@SA) with ribbon-shaped coating and controllable pore size were prepared via the electrodeposition of laminated Zinc coating, further moisture etching and post-modification with stearic acid. In particular, the moisture etching process, which was facile and environment-friendly, were applied to form the rough petaliform structure and adjust the pore size. Through carefully coordinated regulating the electrodeposition time, moisture etching time and post-modification process, the average pore size of the mesh could be precisely tuned in the range from 38 μm to 6 μm. The influences of the textured roughness and chemical composition on the surface wettability were systematically investigated. The Cu@E-Zn@SA exhibited superhydrophobicity with water contact angles of larger than 150° and sliding angles of lower than 8°. Besides, the Cu@E-Zn@SA could maintain their superhydrophobicity after sandpaper abrasion and sand impact for 50 cycles, displaying remarkable environmental durability and mechanical robustness. Moreover, the prepared superhydrophobic meshes could be applied for the on-demand separation of the oil-water immiscible mixture and water-in-oil emulsions with high efficiencies over 99.3%. Thus, these findings may provide insights in constructing robust superwetting metallic meshes with great application potential in oil-water separation.