Engineering homointerface-mediated mixed matrix membrane for propylene/propane separation

Achieving seamless integration between polymer-filler remains a significant challenge in gas separation mixed matrix membranes (MMMs), particularly with glassy polymers of intrinsic microporosity (PIMs). Here, we report a homointerface strategy for fabricating high-performance MMMs by the modulated synthesis of zeolitic imidazolate framework ZIF-8 fillers with amidoxime-modified polymer of intrinsic microporosity (AOPIM-1) oligomers, followed by being encapsulated within the long-chain AOPIM-1 polymer matrix. These AOPIM-1 oligomers serve a dual role: precisely modulating the crystal growth of ZIF-8 and establishing intimate homointerfaces between polymer-filler due to their intervening linker function. This strategy ensures excellent filler dispersion while preserving their interconnected network structure within MMMs, offering abundant percolating nanochannels. The resulting MMMs exhibited remarkably enhanced C 3 H 6 /C 3 H 8 separation performance, with optimal combinations of C 3 H 6 permeability (184.5–267.6 Barrer) and C 3 H 6 /C 3 H 8 selectivity (23.9–28.9) outperforming state-of-the-art metal–organic frameworks (MOF)-based MMMs. This strategy presents an alternative strategy for the design of efficient MOFs/PIMs MMMs in the separation of challenging gas mixtures.