Salt-Resistant Photothermal Materials Based on Monolithic Porous Ionic Polymers for Efficient Solar Steam Generation

The exploitation of salt-resistant photothermal materials is of great importance for practical solar desalination. Herein, we report, for the first time, the synthesis of monolithic porous ionic polymers (PIPs) coated with polypyrrole (PPy) as self-desalting photothermal materials for efficient solar steam generation. Based on their good thermal insulation, the desired mesopores, and the extremely high light absorption (98%), the PPy-coated PIPs exhibit a high evaporation efficiency of 89% under 1 sun irradiation and superior durability in terms of evaporation efficiency in high-salinity (30 wt %) brine. Quite different from the existing salt-resistant photothermal materials by the artificial creation of aligned channels or Janus wettability, interestingly, the self-desalting of our materials depends on their intrinsically porous ionic framework, which could serve as "ions barrier" to shield the cations of saline solution. These findings may provide an opportunity for future design and fabrication of self-desalting photothermal materials by only one-pot synthesis without a further complicated process.