High-filler-loaded MOF-mixed matrix membranes using digital light processing for CO2 and H2 separation

3D printing is reshaping manufacturing by enabling the creation of complex geometries that are challenging to achieve using traditional techniques. Among the various additive manufacturing methods, digital light processing (DLP) stands out for its ability to precisely fabricate intricate structures through patterned, in situ photopolymerization of low viscosity resins. This low resin viscosity makes DLP particularly appealing for producing mixed-matrix membranes (MMMs) with high filler loadings, allowing for controlled membrane thickness and enhanced material performance. This study explores the use of DLP printing to fabricate single and multi-layered MMMs with high metal-organic framework (MOF) loadings and precisely defined thicknesses. MOF-MMMs with up to 60 wt% filler loading were successfully fabricated through radical-mediated ring-opening photopolymerization. The polymer matrix was formulated using cyclic allylic sulfide (CAS) monomers and triethylene glycol dimethacrylate (TEGDMA), while UiO-66 and UiO-66-NH 2 served as the MOF fillers. The MOF/monomer composite resins were extensively characterized for printability prior to membrane fabrication. The printed membranes were systematically evaluated for their gas separation performance, specifically for H 2 , N 2 , and CO 2 permeation. The results demonstrated that the low viscosity resin affords high filler incorporation while maintaining membrane integrity and selective gas transport properties. This study presents the first successful demonstration of MOF-MMM fabrication via DLP 3D printing with high filler loading, opening new possibilities for advanced membrane design and separation applications.