Droplet motion on superhydrophobic/superhydrophilic wedge-shaped patterned surfaces with different micro-morphologies

Superhydrophobic/superhydrophilic wedge-shaped patterned surface (SSWPS) has promising application prospects in water transportation, fog harvesting, etc., and has therefore been widely prepared and studied. However, influences of micro-morphologies of the SSWPS on water transportation and fog harvesting, which may be of great significance, have rarely been reported. Here, we firstly investigated the influences of the micro-morphologies on the water transportation and fog harvesting processes. SSWPSs with different microgrooves were prepared by laser processing, and the influence mechanisms of the micro-morphologies on droplet motion behaviors were then investigated. The different micro-morphologies contributed to dissimilar capillary forces and fluid resistances during the transportation process, thus resulting in the different transport speeds and fog harvesting efficiencies. For regular microgrooves with 0° direction and larger depths, the capillary forces were relatively larger while the fluid resistances were smaller, which led to the faster water transport speeds of the SSWPS. Fog harvesting experiments on different surfaces demonstrated that the SSWPS with faster water transport speed exhibited much higher fog harvesting efficiency, and could achieve long-time continuous harvesting, which was expected to facilitate application of the SSWPS.