Melt Electrospun Reduced Tungsten Oxide /Polylactic Acid Fiber Membranes as a Photothermal Material for Light-Driven Interfacial Water Evaporation.

The development of efficient photothermal materials is the most important issue in solar water evaporation. In this work, melt electrospun reduced tungsten oxide/polylactic acid (WO/PLA) fiber membranes were successfully prepared with improved near-infrared (NIR) photothermal conversion properties owing to strong NIR photoabsorption by the metal oxide. WO powder nanoparticles were incorporated into PLA matrix by melt processing, following which the composites were extruded into wires using a single screw extruder. Subsequently, fiber membranes were prepared from the extruded wire of the WO/PLA composite by melt electrospinning, which is a cost-effective technique that can produce fiber membranes without the addition of environmentally unfriendly chemicals. The melt electrospun WO/PLA fiber membranes, floatable on water due to surface hydrophobicity, were systematically designed for, and applied to, vapor generation based on the interfacial concept of solar heating. With the photothermal WO/PLA fiber membrane containing 7 wt % WO nanoparticles, the water evaporation efficiency was reached 81.39%, which is higher than that for the pure PLA fiber membrane and bulk water. Thus, this work contributes to the development of novel photothermal fiber membranes in order to enhance light-driven water evaporation performance for potential applications in the fields of water treatment and desalination.