Engineering zeolite nanosheets-polymer interface via thermal treatment: crosslinked-PI&RUB-15 membranes for efficient He recovery

Interfacial incompatibility between inorganic fillers and polymer matrix remains a major challenge in developing high-performance zeolite-based mixed matrix membranes (MMMs), especially for the ones employing high-aspect-ratio two-dimensional (2D) nanosheets as fillers owing to the consequently enlarged interfacial area. Herein, a thermally induced crosslinking strategy is proposed to construct covalent Si– O –C linkages between RUB-15 nanosheets with abundant hydroxy groups and a polyimide (PI) matrix, effectively eliminating interfacial defects. Due to the improved interfacial compatibility, the membrane gas separation performance is significantly enhanced, presenting a He permeability of 87 Barrer with an impressive He/CH 4 selectivity of 357, ∼3.2 times as high as that before crosslinking. Furthermore, excellent separation stability is maintained over ten thermal cycling tests, demonstrating superior durability. This study presents a universal and efficient interfacial engineering strategy for fabrication of robust high-aspect-ratio 2D zeolite-based MMMs and highlights its significant potential in advancing next-generation gas separation technologies.