Dual-Liquid-Diode Janus Mesh with Multisuperwettability for Unidirectional Oil–Water Transportation

Natural biological surfaces enable directional liquid transport and storage due to the specific characteristics and surface morphologies. Inspired by these natural mechanisms, it is of interest to have materials with an asymmetric surface energy or structures to achieve unidirectional liquid transportation. Herein, a dual-liquid-diode (DLD) Janus mesh with asymmetric superwettability on the two sides has been designed via electrospraying, with one side being superoleophobic/hydrophilic and the other side being superhydrophobic/oleophilic. The DLD Janus mesh was designed to enable unidirectional transportation of both oil and water in the opposite direction concurrently, in contrast to Janus membranes that were developed for a single liquid. Oil and water can unidirectionally pass through the DLD Janus mesh without an external energy supply in both air and liquid environments. This unique property enables the mesh with high flexibility in controllable multiphase liquid transportation scenarios. The DLD Janus mesh demonstrates promise for future applications in smart liquid separation, on-demand oil–water delivery, and fluid valve technologies.