Spongy polyelectrolyte hydrogel with Janus porous for solar-driven interfacial evaporation and sustainable seawater desalination

This paper inspired by the design principles of Janus materials, and in a continuation of our recent studies on photothermal materials. Herein, we introduce a novel concept of "bottom-up" sponge-like polymer-electrolyte hydrogel (PANS-J) with abundant Janus pore structure and different wettability between upper and bottom sides. Evaporation experiments demonstrate that PANS-J achieves the highest evaporation rate (3.35 kg m-2 h-1)-1 ) and efficiency (93.94 %) under 1 sunlight ((1 kW m-2).-2 ). In addition, the quaternary ammonium cation on PDADMAC effectively separates the anions and cations in the brine, reduces the diffusion of salt ions into the evaporator, prevents premature clogging of the pore structure, and is conducive to the improvement of the long-term evaporation performance of the evaporator, as well as possessing very excellent salt resistance and mechanical properties.