Polyoxometalate-mediated film bearing near-infrared photothermal self-healing property for seawater desalination

Abstract

The use of solar-powered seawater desalination films frequently results in damage, making repairable property a crucial concern. Here, a photothermal self-healing seawater desalination film is created using poly-thioctic aclhydrazine (P-TAH) as the bulk material and Keggin-type polyoxometalate (POM) doped with TAH as an additive. The film’s self-healing ability is supported by the dynamic covalent connections in TAH, while the addition of POM improves mechanical strength and adds photothermal properties. The Young’s modulus increases from 7 to 195 MPa when 1/100 M ratio of POM is added to bulk material. With an energy efficiency of 94.4 %, the produced film’s evaporation efficiency achieves a high value of 2.75 kg m−2h−1. Furthermore, the injured film can be repaired while maintaining nearly the same mechanical strength and evaporation efficiency. The outdoor experiments indicate that the prepared film has a high performance under the irradiation of natural sunlight, which makes its possibility for the further applications. This work demonstrates the unreported photothermal self-healing property of POM-containing materials, in addition to presenting a generic approach for building POM-based seawater desalination films.