Fog collection on wettability-mixed patterned surfaces inspired by multiple biological structures

Fog collection has become one of the effective means to solving water scarcity. Wettability-mixed patterned surfaces exhibit great potential in fog collection. In this article, the desert beetle, honeycomb structures and cactus spines served as an inspiration in the proposal of a bionic pattern of honeycomb and cactus spine coupling (BPHCSC) that can efficiently collect fog. First, a superhydrophobic (SHB) surface was successfully prepared on the surface of 5052 Al alloy through combined electrochemical etching with fluorosilane modification. Subsequently, laser etching technology was used in the precise etching of a superhydrophilic BPHCSC on the SHB surface. Compared with the fog collection efficiencies of a single SHB surface and the honeycomb-like wettability-mixed patterned surface composed of rectangular channels, that of the prepared BPHCSC surface increased by approximately 23.5% and 4.27%, respectively. In addition, a thorough exploration was conducted on the effects of factors, such as the distance between the sample surface and the fog outlet, tilt angle and the number of laser etchings, on fog collection efficiency. This study provides a new idea for fog collection and exhibits a broad application potential in fields, such as microfluidic systems, droplet manipulation and cell screening.