Coalescence-Induced Droplet Jumping Behavior for Atmospheric Corrosion Protection

Coalescence-induced droplet jumping behavior (CIDJB) on superhydrophobic surfaces enables the effective removal of corrosive water films/droplets, thereby showing great potential for marine atmospheric corrosion. However, merely focusing on the superhydrophobic effect is not enough. It is essential to select optimal nanoarchitectures and fine-tune their geometric parameters to achieve a high-efficiency CIDJB and atmospheric corrosion protection. In this study, three kinds of superhydrophobic surfaces with distinct geometrical parameters of microstructures were systematically fabricated. The impact of reaction concentration on the microstructure parameters (diameter, interspace, and height) of superhydrophobic surfaces was investigated, where higher concentrations were found to increase microstructure diameter while reducing height and initially decrease interspace before increasing again. The individual and synergistic mechanisms of how these microstructure parameters affect the droplet self-jumping behavior (droplet surface coverage, droplet average diameter, and anticondensation efficiency) and the corrosion protection performance against marine atmospheric corrosion were analyzed. It was revealed that the spacing of the superhydrophobic surface microstructures is a critical factor influencing both the droplet self-jumping behavior and corrosion protection performance. Smaller spacing can generate larger upward Laplace pressure, thereby accelerating droplet coalescence and jump and facilitating the transition of condensed droplets within the microstructure from partially wetted states to suspended Cassie states. This study enriches the theoretical system of CIDJB and provides design criterion for the development of high-performance anticorrosion superhydrophobic surfaces in marine environments.