Micrometer Groove Array Structures Inspired by Desert Grasses on Curved Substrates for Enhanced Surface Condensation Efficiency.

Drawing inspiration from the microstructures on biological surfaces to create highly efficient water-collecting surfaces is an effective way to address water scarcity. Inspired by the role of the convex and concave grooves on the surface of Namib desert grass in promoting condensation, we show that optimizing the curvature radius improves the condensation rate of droplets. This convex-concave geometry, combined with nanoneedle structures on the groove ridges, facilitates droplet merging and self-removal through jumping, refreshing the condensation site and further enhancing condensation efficiency. Meanwhile, reducing the adhesive resistance in the groove valleys accelerates droplet migration and removal. We believe this design strategy can be applied to a wide range of water collection and phase change heat transfer applications.