Pore-Networked Membranes Formed by In Situ Gelation of Metal-Organic Frameworks

The integration of metal-organic frameworks (MOFs) as fillers with polymers as matrices, known as mixed-matrix membranes, aims to overcome the low processability of MOFs while maintaining their adsorbent properties for separation applications. However, the aggregation of MOF nanoparticles and their poor compatibility with polymers compromise the membrane stability and performance. Here, we report the fabrication of pore-networked membranes (PNMs) by in situ gelating MOF nanoparticles into mesoscale colloidal networks with hierarchical porosities within the polymer matrix. In contrast to most conventional hybrid strategies that rely on the homogeneous dispersion of MOF fillers, PNMs are characterized by an interconnected colloidal MOF network as the continuous porous phase across the whole membrane material. As proof of concept, a series of zirconium-based MOFs was used to fabricate PNMs. We comprehensively studied the effect of MOF ligands on their capability of gelating and forming a continuous MOF phase with homogeneous distribution. Various polymer matrices are screened to tailor membrane fabrication to enhance mechanical stability and improve performance in the uptake of water pollutants. Our PNM strategy provides an alternative pathway to bridge MOF adsorbents and processable polymers for better material performance.