Novel Polymers with Ultrapermeability Based on Alternately Planar and Contorted Units for Gas Separation

Polymers of intrinsic microporosity (PIMs) have been the potential candidates as gas separation membrane materials, because of their high permeability and good processing. Here, three PIMs (PIM-ABAs) with ultrahigh permeability are reported; these are significantly more permeable than the PIM-1 and other PIMs reported and do not lose high selectivity and good processing merit. The introduction of large and rigid planar units alternatively contorted units suppresses the compact packing of polymer chains, resulting in the hierarchical porosity range of 0.5–4.0 nm. The presence of larger pores is responsible for promoting permeability. PIM-ABA-OMEN demonstrates the optimal CO₂ permeability (16 736 barrer), which is 3.95 times more than PIM-1 (4234 barrer) with equivalent gas selectivity and PIM-ABA-EN exhibits the promotion of both permeability and selectivity. After being aged for 186 days, PIM-ABAs still showed the CO₂ permeability above 8000 barrer, which is almost as 2 times greater than that of unaged PIM-1. This work provides a new strategy for the preparation of PIMs with enhanced gas separation performance.