Patterned\nHybrid Surfaces for Efficient Dew Harvesting

Dew harvesting, minimally influenced\nby climate and geographical\nlocations, is an ideal method for addressing water shortage problems.\nSuperhydrophilic surfaces, characterized by their highest affinity\nfor water, are particularly attractive for this purpose as they can\nattract more water molecules via condensation. However, a significant\nchallenge arises from the high surface capillary force that impedes\nwater from sliding down and being effectively collected. The resulting\nwater film on the superhydrophilic surface tends to stay around the\nedge of the water collection surface, leading to evaporation loss\nand reduced collection efficacy. To overcome this problem, triangular\npatterns with low surface adhesion to water were introduced at the\nedge of superhydrophilic surfaces. This modification, achieved through\na wet chemical method and masked oxygen plasma treatment, has significantly\nimproved the efficiency of water collection. Results indicate that\nthe hybrid surface reduced the time for the first water droplet to\nslide down by half and increased water collection efficiency by 78%\ncompared to uniform superhydrophilic surfaces and by 536% compared\nto uniform superhydrophobic surfaces under a relative humidity of\n55% with a temperature difference of 15 °C. The underlying principles\nwere elucidated through computational simulations, and the mechanisms\ndriving the enhancement in collection efficiency were explained.