MOF glass-based membranes: a promising platform for advanced separation

Metal-organic framework (MOF) glasses represent an emerging frontier in porous materials that uniquely combine the structural tunability of crystalline MOFs with the superior processability of traditional polymers. Unlike their crystalline counterparts, MOF glass-based membranes inherently eliminate grain boundary defects and display excellent thermal stability. The melt-quenching process also enables the formation of unsaturated metal sites and coordination defects, which can be tailored to optimise adsorption affinity, pore size distribution, and diffusion pathways. This review provides a comprehensive overview of the formation mechanisms, structural features, classifications, and advanced characterisation of MOF glass-based membranes, with a focus on their roles in high-selectivity and scalable gas separation. It further discusses the design principles of meltable MOFs, the structural evolution during the crystal-to-glass transition, and critical structure-property relationships. Key challenges in fabrication and industrial integration are evaluated, and future research directions are proposed to guide the development of MOF glass membranes as a transformative platform in separation science.