Bioinspired Underwater Respirable Superhydrophobic Skin with a Microcone–Nanoparticle Structure for Sustainable Drag Reduction

Superhydrophobic (SH) surfaces have served as a key strategy to decrease flow resistance via gas-liquid interfaces in numerous fields such as pipeline transportation, microfluidics, the shipping industry, and so forth. However, an underwater SH surface with both good drag reduction and plastron restoration from a fully wetted state remains challenging. Inspired by the hairy structure of water spiders, herein, an underwater respirable skin (URS) with a microcone-nanoparticle structure is demonstrated. URS with different geometric parameters is achieved through laser microfabrication and chemical vapor deposition. The plastron can be completely restored from the fully wetted state after 11.6 s of air jetting, and a drag reduction rate of 15.7% ± 0.2% can be achieved. The theoretical and numerical results reveal a contradictory effect between drag reduction and plastron restoration. Our study suggests promising comprehensive perspectives for marine vehicle coatings and methodologies for sustainable drag reduction surfaces, considering both plastron restoration and the drag reduction rate.