Gas separation with binary-cooperative heterogeneous membranes

Advanced polymer membranes exhibit competitive performance in gas separation. However, rationally designing a polymer membrane with high gas separation performance and structural robustness simultaneously remains challenging. Herein, we present a microzone interfacial polymerization approach to reconstruct the polymer network through the rearrangement of attached functional groups, forming a heterogeneous structure with a crumpled morphology. Unlike common crumpled membranes with homogeneous structures, the heterogeneous structure with a discovered microphase separation endows the membrane with independent and cooperative dual-function regions. The peaks, with more amides as CO2-philic sites, are functionalized as fast CO2 transport channels, whereas the stress release effect via the deformation process maintains a high free volume. Valleys, with more rigid phenyls, demonstrate both enhanced CO2 diffusion and compaction resistance. The cooperative effects of dual-function regions significantly improve the structural robustness, and the optimized membrane exhibits an approximately 300% increase in CO2 permeance and CO2/N2 selectivity compared with its homogeneous counterparts under 1.0 MPa, which is also one order of magnitude greater than that of state-of-the-art membranes. This approach offers a potential pathway for developing more durable polymer membranes suited for harsh environments, which could expand the range of gas separations feasible with membrane technology. Designing polymer membranes with high gas separation and structural robustness is challenging. Here the authors use a microzone interfacial polymerization strategy, forming a heterogeneous crumpled membrane, for effective CO2/N2 separation.