Incorporating hydrogen bonding networks in microporous polymer membranes for high-flux hydrocarbon separation

Polymer membranes have been most commonly utilized in gas separations, while they often suffer from the trade-off between membrane permeability and selectivity, which arises from the inherent coupling between polymer chain rigidity and interchain spacing. Here, we propose a hydrogen bonding network strategy, where hydrogen bonding acceptors are incorporated into amidoxime-functionalized polymer of intrinsic microporosity (AO-PIM) membranes to in situ construct hydrogen bonding networks with amidoxime groups, and to modulate the interchain spacing/micropore structure in AO-PIM. Especially, 2,2′-bipyridine endows AO-PIM membranes with appropriate match between polymer chain rigidity and interchain spacing, leading to dramatically enhanced C 3 H 6 permeability of 262 Barrer, 2.9 times higher than AO-PIM membranes, with a C 3 H 6 /C 3 H 8 selectivity of 24 under mixed-gas tests, surpassing all the reported polymer membranes and most mixed matrix membranes. We envision this scalable, generic hydrogen bonding network strategy opens an alternative avenue for polymer membranes to break the trade-off effect.