Laser-architected dual-bionic fog catcher: a hierarchical wettability-engineered system facilitating droplet harvesting

Freshwater scarcity is a critical global issue, exacerbated by inefficiencies in conventional water treatment and harvesting methods. A biomimetic fog-catching cage (FCC), inspired by cactus spines and lotus leaves, fabricated by advanced laser etching, is proposed. The wettability of the bottom plate and lattice structure are precisely controlled. The device is optimized in terms of fog collection efficiency and drainage efficiency. Experimental results show a 463.45% increase in fog collection compared to conventional copper sheets with same projection area. The FCC device demonstrates outstanding cyclic stability and long-term water collection efficiency, with further enhancement through multi-layer integration. The collected water provides irrigation application for crops like coriander, scallions, and spinach in urban green planting. For outdoor planting with harsh climate, the anti-icing properties of the device ensure reliable usage. This research presents a sustainable, efficient method for water collection, offering significant potential in agriculture, environmental conservation, and resource management as a solution to the global water crisis.