An All-Hydrophobic Fluid Diode for Continuous and Reduced-Wastage Water Transport

Abstract

Directional water transport that occurs in natural insects and plants is important to both organisms and advanced science and technology. Despite the many studies conducted to facilitate directional liquid transport by constructing double-layered hydrophilic/hydrophobic materials, it remains difficult to achieve continuous water transport and reduce liquid wastage due to the hydrophilic regions. Herein, a directional water transport fabric (DWTF) was fabricated using a simple single-side coating method based on entirely hydrophobic materials. With coating thicknesses of 13-29 μm, the fabric could guide the continuous water motion from the coated to the uncoated side and can be utilized as a "liquid diode". In addition, the DWTF exhibited a water wastage reduction during the transport process, benefiting from the intrinsic hydrophobic properties of the material. Moreover, a plausible mechanism of water transport is proposed to explain the water droplet transfer in the bilayered hydrophobic materials. Consequently, the resulting DWTF exhibited an excellent accumulative one-way transport capability (AOTC) of 965.7% and a desirable overall moisture management capability (OMMC) of 0.92. This work provides an avenue for fabricating smart fluid delivery materials to various applications such as flexible microfluidics, wound dressing, oil-water separation processes, and engineered desiccant materials.