Regulating the Hydrophilicity\nof Hyper-Cross-Linked\nPolymers via Thermal Oxidation for Atmospheric Water Harvesting

We explore the thermal oxidation of hyper-cross-linked\npolymers\nto enhance their hydrophilicity and efficacy in atmospheric water\nharvesting. Comprehensive chemical and physical characterizations\nare used to confirm the successful incorporation of polar oxygen moieties\nand the preservation of porosity upon thermal treatment. Newly introduced\noxygen-based functional groups significantly improve water sorption\nproperties, increasing total water uptake capacities by up to 400%\nand shifting water uptake onsets to significantly lower relative humidity.\nWe also investigate the regeneration of oxidized hyper-cross-linked\npolymers after water sorption to probe their potential for multiple\nwater harvesting cycles and reuse. Our findings outline a simple and\ncost-effective postsynthetic modification route for optimizing porous\norganic polymers for more sustainable and efficient atmospheric water\nharvesting.