A superhydrophobic dual-scale engineered lotus leaf

A surface was created with the same superhydrophobic property as the lotus leaf (lotus effect) by dipping of sandblasted porous alumina into polytetrafluoroethylene (PTFE, Teflon (R): DuPont (TM)) solution. The fabricated engineered lotus leaf had PTFE dual-scale structures. This fabrication process has several advantages, including low fabrication cost, simplicity and easy coverage of a large area. The sandblasted porous alumina template was fabricated by sandblasting of an aluminum sheet and anodization in oxalic acid. To obtain PTFE dual-scale structures, PTFE replication based on the dipping method was used, with a 0.3 w% PTFE solution. To remove the aluminum and alumina layers, wet etching by chromic and phosphoric acid mixed solution and liquid HgCl2 solution was used. The fabricated surface has a superhydrophobic property whose apparent contact angle of the PTFE dual-scale structures was approximately 165 and sliding angle is less than 2.