High-efficient and robust fog collection through topography modulation

Janus wettable material is considered one of the most promising candidates for fog collection. However, the applications of fog collectors are confined by many weaknesses nowadays, such as tedious fabrication methods, low mechanical stability and durability, and poor collecting efficiency. Among them, improving fog harvesting efficiency is a big challenge to be overcome. Herein, a series of hydrophobic-superhydrophilic Janus system has been successfully fabricated by a facile and eco-friendly method including etching and interface modification. Importantly, under the inspiration of natural creatures, the topography of hydrophobic surface in Janus system can be modulated by modifying substances with different low surface energy, effectively improving the fog collecting performance, and obtaining an excellent fog harvesting efficiency of 3718 mg·cm−2·h−1 in unenclosed fog environment. The underlying mechanism is designed to discuss the enhancement of fog collection in terms of fog capture, drop coalescence and drop transportation. Meanwhile, it is recyclable and durable even maintained for at least 5 months. Moreover, it exhibits good stability during mechanical, thermal and ultraviolet (UV) resistance testing. Overall, the findings open up a new avenue to design Janus materials for efficient fog harvesting by regulating micromorphology and promote a promising candidate for addressing water scarcity.