Resolution-Enhanced Vat Photopolymerization of Emulsion-Templated Foams Using Metal−Organic Frameworks

Abstract

3D printing (3DP) is an emerging technique for improving metal−organic framework (MOF) processability utilizing polymeric scaffolds to preserve critical attributes like high surface area and activity toward toxic gases; however, these capabilities rely heavily on maintaining open MOF accessibility. In 3D-printed polymerized high internal phase emulsions (polyHIPEs), a major challenge is the severe loss of print resolution caused by light scattering and subsequent overcuring during the polymerization process. To overcome this limitation, we incorporated three distinct MOFsUiO-66-NH2, MOF-808, and PCN-250into the polyHIPE resins at 1 wt % to evaluate how their varying properties, specifically their different light absorption abilities, hydrophilicity, and particle sizes, impact print resolution. Among the tested materials, UiO-66-NH2 proved to be a highly effective light absorber, mitigating emulsion light scattering and yielding the greatest overall improvement in resolution. We observed that increasing the loading of UiO-66-NH2 effectively decreased light penetration depth, where an optimal loading of 4 wt % UiO-66-NH2 successfully prevented overcure and achieved the correct, intended print dimensionality. Ultimately, MOF type and loading concentrations are critical tunable parameters for controlling light scattering and minimizing overcure, and optimizing these factors significantly enhances the structural resolution and functional quality of 3D-printed MOF-polyHIPE monoliths. Consequently, these findings establish a critical foundation for designing functional MOF-polymer materials that successfully balance high structural resolution with open, porous accessibility.