Enhanced Fog Harvesting through Capillary-Assisted Rapid Transport of Droplet Confined in the Given Microchannel-Yongmei Zheng

A novel integrated bioinspired surface is fabricated by using an innovative capillarity-induced selective oxidation method, to achieve the combination of the fog-collecting characteristics of a variety of creatures, i.e., the micronanostructures of spider silk, the wettable patterns of desert beetle, the conical structure of cactus spine, and the hierarchical microchannel of Sarracenia trichome. The fog is captured effffectively via multistructures on the cone tips, and captured droplet is collected and confifined in the microchannel to realize rapid transport via the formation of wettable pattern on the surface and the introduction of wettable gradient in the microchannel. Consequently, the fog harvest effiffifficiency reaches 2.48 g/h, increasing to nearly 320% compared to the normal surface. More interestingly, similar to Sarracenia trichome, the surface also presents two transport modes, namely, Mode I (water transport along dry microchannel) and Mode II (succeeding water slippage on the water fifilm). In Mode II, the velocity of 34.10 mm/s is about three times faster than that on the Sarracenia trichome. Such a design of integrated bioinspired surface may present potential applications in high-effiffifficiency water collection systems, microflfluidic devices, and others.