Tailored Polymer‐Zeolite Imidazolate Framework Membranes for Aperture‐Matched C4 Hydrocarbon Separation

Abstract The integration of metal‐organic frameworks (MOFs) with polymers for efficient C4 hydrocarbon separation membranes remains challenging, primarily due to inherent phase incompatibility. This work presents an in‐situ synthesis strategy for polymer‐zeolitic‐imidazolate frameworks (polyZIF), utilizing polymer‐metal‐ligand coordination bonds combined with structural directing agents to produce crystalline microporous frameworks. With an accessible BET surface area of 261 m 2 g −1 and a permanent porosity of ca. 4.42 Å, polyZIF membrane demonstrates butadiene permeance (∼332 GPU) and the selectivity over n ‐butene, n ‐butane, iso‐butene, and iso‐butane (17.2, 28.1, 21.5, and 34.8) under mixed gas conditions, respectively. Demonstrating practical scalability, the improved dispersibility and reduced interfacial defects in polyZIF facilitates fabrication of large‐area defect‐free membranes (up to 80 cm 2 ) while maintaining robust C4 separation performance. This advancement not only establishes a novel preparation for constructing polyZIF membranes with C4 hydrocarbon molecular‐sieving capability but also provides critical insights into industrial application of ZIF‐based polymer membranes.