Gas film transportation on asymmetric superhydrophobic mesh surfaces for excellent drag reduction and antiscaling properties

Manipulation of gas in an aqueous environment is fundamental to both academic research and industrial applications. In particular, the gas film on a superhydrophobic surface, referred to as a plastron, has fascinated scientists due to its potential applications, including drag reduction, antifouling, gas-involving reactions, and gas transport. However, most gas manipulation strategies focus on the transportation of bubbles. An effective method for the facile manipulation of plastrons has yet to be explored. In this work, we propose a high-performance manipulation strategy for plastrons that uses the capillary pressure difference generated by connected sparse and dense superhydrophobic mesh surfaces (S-D-SHM). Plastrons can be transported directionally, spontaneously, repeatedly, and counterbuoyantly (up to a 30° tilt angle) between asymmetric SHMs. This method, which requires no external energy input or human intervention, can provide on-demand plastron replenishment for SHMs (8 times), significantly enhancing plastron stability. Furthermore, the S-D-SHM achieves a 142% improvement in water impact resistance due to the automatic adjustment of the plastron pressure. Owing to the long-term isolation effect of the plastron, the S-D-SHM shows an excellent drag reduction effect (23.7% drag reduction rate (D_r)) and antiscaling performance (93.3% antiscaling rate). This facile and effective strategy simplifies plastron manipulation and can advance the development of stable superhydrophobicity under complex wetting conditions.