Gas separation with binary-cooperative heterogeneous membranes.

Abstract

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.