Dual liquid-assisted single-layered Janus mesh membrane with controllable and efficient directional water transport for multiple applications

Janus porous membranes with anisotropic interfaces exhibiting directional liquid transport properties have emerged as important tools for addressing real-world issues, such as oil-spill cleanup and fog collection. Here, a single-layered Janus mesh membrane with asymmetric wettability and a well-tuned hydrophilization depth is prepared using an ethanol-assisted floating method. Consequently, the well-regulated hydrophilization depth combined with a water-assisted strategy achieves controllable and efficient directional water transport properties, which also gives rise to a high anisotropic critical breakthrough pressure. In addition, the water-assisted controllability can form an on–off gate capable of allowing or blocking water to pass through upon request. Moreover, we theoretically and experimentally determine the changeable contact area as important in directional water transport properties. Controllable directional water transport behavior with a high pressure difference has been demonstrated in on-demand oil–water separation and intravenous infusion, whereas the efficient directional water transport properties have potential applications in fog collection. Overall, this work provides a new idea for the preparation of a single-layered multifunctional Janus mesh membrane with a high anisotropic critical breakthrough pressure and opens an avenue for controllable and efficient directional water transport properties for diverse applications.