Positively Charged Polymer-Brush MOFs for Large-Area, Pressure-Resistant Gas Separation Membranes.

Abstract

Scalable fabrication of high-performance gas separation membranes remains a major challenge for energy-efficient gas purification. Industrial translation of pressure-resistant mixed matrix membranes (MMMs) is largely impeded by the dispersion instability of nanofillers under rapid, non-equilibrium manufacturing conditions, which leads to uncontrollable aggregation and interfacial defects during processing. Here, we present a universal "pre-occupation and post-activation" strategy to construct positively charged polymer-brush metal-organic frameworks (MOFs). This approach endows the fillers with a dual-stabilization mechanism: electro-steric effects ensure static dispersion stability, while a hydrogen-bonding-driven interfacial interlocking mechanism maintains stability during dynamic processing. Together, these mechanisms synergistically facilitate the seamless integration of nanofillers within ultrathin selective layers. This design allows roll-to-roll production of 1 m-wide, pressure-resistant mixed matrix composite membranes (MMCMs) with tunable CO₂ separation performance. The resulting MMCMs deliver outstanding CO₂/CH₄ and CO₂/N₂ separation under industrially relevant pressures, reducing the required membrane area by more than an order of magnitude compared with laboratory-scale membranes. A spiral-wound module with an effective area of 0.4-2 m² further validates the scalability and operational robustness. This work overcomes a long-standing barrier in MMM processing, marking a significant step toward industrial implementation of MOF-based, energy-efficient gas separation technologies.