Size-Tailored MOF Fillers in Poly(vinylamine) Matrices: Interfacial Engineering for Efficient CO2 Separation Membranes

The development of high-efficiency CO 2 separation membranes represents a critical pathway toward achieving the goal of carbon neutrality. In this work, we present a size-controlled strategy to fabricate a high-performance mixed matrix membrane (MMM) using poly (vinylamine) (PVAm) matrices incorporated with zeolitic imidazolate framework (ZIF-8) filler (size range: 98-1200 nm). Systematic investigation reveals that ZIF-8 particle size critically governs interfacial compatibility with the PVAm matrix, directly impacting CO 2 separation efficiency. Both significantly larger or smaller particles than 130 nm tend to induce non-selective interfacial voids at the polymer-filler interface. Optimal performance is achieved with 130 nm ZIF-8 fillers, which exhibits superior dispersion stability in PVAm solutions, as evidenced by the highest zeta potential values. The resultant MMM exhibits high separation performance under 0.1 MPa feed pressure, achieving a CO 2 permeability of 455.06 GPU and CO 2 /N 2 selectivity of 42.36, higher than those of the pure PVAm-based membrane without ZIF-8 filler. This work provides valuable guidance for the design of high-performance CO 2 separation membranes, advancing the development of sustainable carbon management technologies.