Waterdrop-assisted efficient fog collection on micro-fiber grids

Fog collectors can mitigate water scarcity by capturing droplets from fog streams. Previous research focuses on improving aerodynamic design and surface characteristics to enhance collection efficiency. However, limited attention has been given to micro-meter level fog-intercepting structures and the impact of waterdrop clogging. This study investigates the fog collection process on microfiber grids with varying fiber spacings and diameters. Waterdrops clog the grid openings with a pattern that small waterdrops satelliting large ones. Due to the small fiber diameter, the waterdrops are "visible" to incoming airflow and strongly affect fog droplet interception. The large waterdrops deflect incoming fog flow towards the small ones, and the small waterdrops efficiently capture the fog droplets. Consequently, the fog collectors based on microfiber grids demonstrated an exceptional water collection efficiency of up to 21.4%. The micro-fiber grids require minimal material usage and no special surface treatment, highlighting a great potential in fog water collection. Additionally, this work provides a novel design strategy of fog collector, i.e., reducing the size of the fog-intercepting structure to directly capture fog droplets by waterdrops.