Polymers of intrinsic microporosity for membrane-based precise separations

Polymer materials have been extensively utilized in diverse separation fields, especially in membrane-based nanotechnologies for gas and liquid separations. The membrane separation has proven to be highly promising to address energy, resource, and environmental challenges. However, progress in polymer separation membranes has been constrained by its inherent limitation that is the trade-off relationship between permeability and selectivity. Polymers of intrinsic microporosity (PIMs), as promising building materials have received substantial attention for membranes separation over the last decade. Different from conventional polymers, PIMs are a new class of microporous polymer materials that possess favorable solubility, well-defined pore architectures, and steerable post-modification due to the designability of synthesis monomer at a molecular level. In this review, we first discuss the state of the art of PIMs-based separation membranes and highlight their critical merits for membrane design. We then describe rational strategies towards fabricating PIM-based membranes and their applications, with a focus on the recent advances in gas separation, pervaporation (PV), nanofiltration (NF) and organic solvent nanofiltration (OSN). Furthermore, the physical aging issue of PIMs and its advanced strategies are also discussed and summarized. Finally, a concise conclusion, current challenges, and future opportunities on the development of PIM-based membranes are additionally discussed.