Biomimetically Assembled Sponge‐Like Hydrogels for Efficient Solar Water Purification

Abstract Hydrogel‐based evaporators for interfacial solar vapor generation (SVG) have emerged as a promising and sustainable strategy for freshwater production. Nevertheless, developing a green and simple approach in the fabrication of porous hydrogel‐based evaporators with tunable porous structures and superior mechanical properties continues to be a challenge. Herein, cryo‐assembled templating and polymerization (CTP) is proposed as an ecological, simple yet effective approach to synthesizing sponge‐like hydrogels (SPHs) with outstanding mechanical properties. Moreover, inspired by the structural geometry of conifer plants of radially aligned microchannels and vertical vessels granting impressive water transportation abilities, the polyzwitterionic SPH evaporators with biomimetically assembled structure (B‐SPH) raise the water transport rate by up to nearly 2 orders of magnitude compared to bulk hydrogels. The B‐SPH also enables an SVG rate up to ≈ 3.45 kg m−2 h−1 under one sun irradiation and an energy efficiency of ≈ 95%. In addition, the as‐prepared materials feature stable mechanical properties and SVG performance even after being rolled, folded, and twisted over hundred times. It is anticipated that the B‐SPH prepared by CTP method provides insights into scalable hydrogel‐based evaporators with elaborate porous structures and durable mechanical properties in an energy‐efficient manner.