Multifuctional Janus Materials for Rapid One-Way Water Transportation and Fog Collection.

A novel micronano wire channels Janus membrane (WCJM) was fabricated by a convenience spraying method. We prepared a series of samples with different (super)hydrophobic energy barriers and studied the effects of WCJMs on one-way transportation and fog collection. The droplets can be one-way transported from the (super)hydrophobic side to the superhydrophilic side, forming a transport channel when they contact the superhydrophilic micronano wire under hydrostatic pressure. In the experiment, when droplets touch the exposed micronano wires, they will be rapidly absorbed by the superhydrophilic side. However, when the superhydrophobic energy barrier is thick and the superhydrophobic layer completely covers the micronano wires on the substrate surface, the droplets cannot achieve one way transport behavior. Besides, we observed three different fog collection modes. They have a significant difference in fog collection efficiency. In WCJM-3, the superhydrophobic side collects fog in a dropwise condensation mode, and then transported to the superhydrophilic side through the micronano wire channels for storage, with the highest fog collection efficiency (1.1 g/cm2·h). The results show that the WCJM surface not only makes full use of the difference in wettability and micronano wire structure to promote the droplets one-way transportation, but also improves the fog collection performance by accelerating surface regeneration, which has potential application value in fog collection, droplet treatment and related engineering.