Tailoring Gas Transport Properties in MOF-Based Mixed Matrix Membranes: The Role of Filler Morphology and Surface Functionalization
Year: 2026
Type: preprint
Abstract: The development of high‑performance mixed‑matrix membranes (MMMs) for gas separations relies on precise control of filler morphology and optimized polymer–filler interactions. In this study, we elucidate how crystal size, morphology, and surface functionalization of the perfluorinated metal-organic framework (MOF) F4_MIL‑140A(Ce) influence the gas transport properties of MMMs based on Pebax® 1657 and Matrimid® 9725 matrices. Through systematic modulation of reaction conditions, we synthesized sub‑micrometric F4_MIL‑140A(Ce) particles with tailored size and aspect ratio, achieving improved dispersion and interfacial contact within the polymer phases. A post‑synthetic grafting strategy using stearic acid further enhanced the compatibility of the MOF without altering crystallinity, pore accessibility, or CO 2 adsorption behavior, as confirmed by powder X-ray diffraction, scanning electron microscopy, and sorption analyses. MMMs prepared with the surface-functionalized MOF displayed improved polymer–filler adhesion, minimized interfacial voids, and significantly enhanced gas transport properties. In particular, the Pebax® 1657-based MMMs approached the 2008 Robeson upper bound for CO 2 /N 2 separation, driven primarily by increased CO 2 solubility. In contrast, Matrimid® 9725 MMMs exhibited substantial improvements in H 2 /N 2 and O 2 /N 2 selectivity, linked to enhanced diffusivity. The insights presented in this work provide a rational framework for engineering MOF–polymer interfaces and advancing membrane‑based gas separation and CO 2 capture technologies.
Source: ChemRxiv
Language: English
Subfield: Filtration and Separation
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223410518