Application of ZnO/epoxy resin superhydrophobic coating for buoyancy enhancement and drag reduction

The air layer produced by superhydrophobic coating can change the contact mode between the surface and water, which grants it potential application prospects in buoyancy enhancement and drag reduction. However, the buoyancy mechanism of superhydrophobic coating still lacks systematic understanding. Herein, a superhydrophobic glass was prepared by coating a ZnO/epoxy resin (ER) solution onto the glass, which was subsequently reacted with mixed acetic acid, stearic acid, and ethanol solution. The introduction of superhydrophobic coating changes the contact mode between the surface of the glass and water, and the coated position will affect the final floating state of superhydrophobic glass. Edge-coated, top-coated and whole-coated glass can float on the surface of water due to surface tension. In addition, whole-coated glass possesses the highest loading capacity of 7.48 g. Furthermore, the whole-surface coating method was applied to a model boat to investigate the drag reduction effect of superhydrophobic coating on a model boat at terminal velocity. The drag reduction efficiency of superhydrophobic model boat increased from 5 % to 21 % with the increase of pulling force, which demonstrating a good drag reduction effect. Thus, this superhydrophobic coating may offer a relevant strategy for buoyancy enhancement and drag reduction in practical applications.