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

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 m² 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 cm²) 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.