In Situ Polymerized Poly (p‐phenylenediamine)/Polyethylene Oxide Mixed Matrix Membranes for Efficient CO ₂ /N ₂ Separation

The trade‐off effect of polymer membranes induced by molecular chains entanglement and tight packing remains a key bottleneck restricting their widespread application in the carbon capture field. This study fabricates a novel facilitated transport mixed matrix membrane by employing polyethylene oxide (PEO) as the continuous phase and poly (p‐phenylenediamine) (PpPD) as the dispersed phase through an in‐situ polymerization strategy. Low‐concentration of PpPD nanoparticles can be uniformly dispersed in the PEO cross‐linked network, which not only modulates the PEO chains packing, restricting its segmental motion, but also significantly enhances the CO 2 /N 2 separation performance of the membrane via CO 2 ‐philic amino groups in PpPD. This strategy effectively avoids the interfacial defect between PpPD fillers and PEO matrix in traditional technology, and the optimized membrane of IP/PEO achieves CO 2 permeability of 721.5 Barrer and CO 2 /N 2 selectivity of 49.0, which exceeds the 2008 Robeson upper bound.