3D-Shape Recoverable Hydrogel with Highly Efficient Water Transport for Solar Water Desalination

Porous hydrogels have been developed to be highly efficient interfacial solar vapor generation materials for obtaining affordable freshwater supplies. However, realizing hydrogel materials with portability, adequate water supply, and durable mechanical properties remains challenging. Herein, a scalable and portable hydrogel with 3D-shaped recovery, highly efficient water transport, and robust mechanical stability is reported, which is prepared by foaming polyvinyl alcohol (PVA) and modification of phosphotungstic acid (PTA). Due to the interconnected porous structure and highly permeable polymer network, the PVA/PTA-PH hydrogel has good repetitive compressibility and rapid shape recovery when in contact with water. Combined with light-absorbing nanoparticles, the PVA/PTA-PH hydrogel presents an impressive solar evaporation rate of 3.876 kg m −2 h −1 and a photothermal conversion efficiency of ≈94% under 1-sun irradiation. With 3D-shape recovery and highly efficient water transport, the compressed hydrogel can be quickly unfolded without human intervention and restored to five times the original size for the working state. The good portability, excellent seawater desalination performance, and simple preparation process are anticipated to make the PVA-/PTA-PH hydrogel a promising material to continuously and conveniently produce pure water from seawater.