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Porous organic polymers (POPs) have evinced a huge potential for membrane-based separations owing to their impressive surface areas, high mesopore ratio, superior chemical stabilities, and catalytic abilities. In this study, for the first time, an o-hydroxy porous organic polymer (POP) thin film was in situ generated atop a (polyacrylonitrile) HPAN membrane support via diazo-coupling reaction under mild conditions. Analysis by FT-IR, XPS and SEM confirmed the successful formation of a coherent, thin POP nanofilm. Zeta potentials and water contact angle measurements demonstrated that the resultant POP film was hydrophilic (water contact angle = 48°) and negatively charged because of the abundance of hydroxyl groups. The roles of synthesis parameters (e.g., the solution pH and the reaction time) in the membrane microstructure and separation performance were explored in detail. The best-performing composite membranes show a high pure water permeability (66.5 L m−2h−1 bar−1), superior dye retentions (RCR = 99.6%, RDR = 98.0%, RMB = 98.8%), and low divalent salt retention (

Membrane-based separation processes can efficiently capture CO2 and reduce energy consumption. However, the synthesis of a CO2-philic material which can replace traditional gas separation materials for advanced membrane separation faces numerous challenges. In this paper, we report the incorporation of porous organic polymers (POPs) and low-molecular-weight polyethylene glycol (PEG 400) into Pebax 1657 for the fabrication of a CO2-philic mixed matrix membrane for CO2 capture. The POPs, which contained azo bonds and phenolic hydroxyl groups, exhibited CO2-philic and N2-phobic properties. PEG 400, which possesses ethylene oxide (EO) units with a polar ether group, enhanced the CO2 permeability and CO2/N2 selectivity. This CO2-philic membrane showed CO2 permeability of 392 Barrer and CO2/N2 selectivity of 112, which surpassed the upper bound (2019). This membrane could be a widely applicable tool for improving CO2 capture with advanced membranes.