Design Strategy for Metal–Organic Frameworks-Based Mixed Matrix Membranes Incorporating Polymer Infiltration

Abstract

Polymer infiltration into the pores of metal–organic frameworks (MOFs) during the fabrication of mixed matrix membranes (MMMs) has been demonstrated to profoundly reshape the internal pore environment. However, the impact of this phenomenon remains insufficiently addressed in current membrane design strategies. In this study, we propose an infiltration-conscious design framework grounded in molecular dynamics simulations. This framework examines the interaction between flexible poly(vinylamine) (PVAm) chains and five representative MOFs. A subsequent structural analysis, conducted after the infiltration process, revealed alterations in the pore-limiting diameters (PLDs), which are contingent upon the structural framework. These alterations, in turn, influence the accessibility of molecular entities and the pathways through which gas transport occurs. Diffusion simulations have been instrumental in confirming that such structural reconfigurations modulate the separation performance. To emulate more realistic operational environments, we constructed explicit MOF–polymer interface models and analyzed the infiltration behavior and interfacial interactions. This extended modeling confirmed the tendency of PVAm chains to penetrate MOF pores and revealed framework-specific anchoring mechanisms. Our findings demonstrate that polymer infiltration can induce synergistic structural effects that enhance molecular sieving performance, thereby providing meaningful insights for experimentalists in the rational design of high-performance MMMs.