Hydrophilic Microporous Polymer Membranes: Synthesis and Applications

Ion and water transfer in subnanometer-sized confined channels of hydrophilic microporous polymer membranes show enormous potential in tackling the ubiquitous trade-off between permeability and selectivity for energy and environment-related membrane technologies. To this end, a variety of hydrophilic polymers of intrinsic microporosity (HPIMs) have been developed. Herein, the synthetic strategies toward HPIMs are summarized, including post-synthetic modification of polymers to introduce polar groups (e. g., amines, hydroxy groups, carboxylic acids, tetrazoles) or charged moieties (e. g., quaternary ammonium salts, sulfonic acids), and the polymerization of hydrophilic monomers. The advantages of HPIM membranes over others when employed in energy conversion and storage, acid gas capture and separation, ionic diodes, and ultrafiltration, are highlighted.