Ultrafast droplet transport in bioinspired double V-shaped structure for fog harvesting

To address global water scarcity, fog harvesting offers a promising solution, especially in high-humidity regions. However, conventional bioinspired fog harvesters often suffer from slow droplet transport due to the need for droplet coalescence before overcoming surface adhesion and friction. Inspired by the micro-scale grooves on Sarracenia trichomes and the macro-scale V-shaped edge formed during hummingbird tongue deformation, we developed a fog harvesting device with a Double V-shaped Macro-Micro Structure (DVMS). In this design, capillary forces within the micro-scale V-shaped grooves enable low resistance droplet transport, while the macro-scale V-shaped edge at the bottom effectively shortens the droplet contact line, thereby facilitating droplet detachment from the surface. Under a fog flow of 2 mph (0.89 m s -1 ), the device achieves a fog harvesting rate of 4050 mg cm -2 h -1 , corresponding to a 356.63% enhancement over bare aluminum with the same area. In addition, the harvester exhibits excellent corrosion resistance, cyclic durability, and long-term stability, offering an effective strategy for sustainable fog harvesting.