Recent progress in PIM-1 based membranes for sustainable CO₂ separations: Polymer structure manipulation and mixed matrix membrane design

Greenhouse gas separation, storage, and utilization are extremely urgent due to the growing climate problems and resource shortages. Polymer-based membrane separation as one of the most promising technologies for large-scale and high-efficient gas separation has been studied extensively for decades in virtue of its low-cost and energy saving process. The emergence of ultra-permeable polymers of intrinsic microporosity (PIMs), particularly the PIM-1 with excellent solubility in common solvents, has attracted a lot of research interest towards next generation high-performance membrane fabrication for CO₂ separations. However, despite the high gas permeability and excellent workability, PIM-1 exhibits relative low gas selectivity and suffers from significant physical aging, therefore the research focused on improving the permselectivity and long-term stability of PIM-1 based membranes has been developed rapidly in recent years. Given that, the latest progress of modification strategies for PIM-1 based membranes are summarized in two perspectives: design and modification of PIM-1 intrinsic structure and fabrication of PIM-1/nanofiller mixed matrix membranes, especially for CO₂ separations. Furthermore, the advantages and limitations of existing researches are discussed, and the feasible future research directions are boldly prospected, hoping to be instructive for developing PIM-1 based high-performance membranes for crucial gas separations like CO₂ capture, H₂ purification and natural gas purification.