Facile Interfacial Cross-Linking of a Poly(aryl ether ketone)-Derived Reactive Macromonomer for High-Performance Organic Solvent Nanofiltration Membranes

Developing solvent-resistant membranes is critical for organic solvent nanofiltration (OSN). Although poly(aryl ether ketone) (PAEK) exhibits exceptional chemical stability, its application has been limited by the reliance on aggressive processing media, such as corrosive protonic acids or high-boiling-point polar aprotic solvents. In this work, a soluble acyl chloride-functionalized PEKK (PEKK-COCl) is synthesized to enable the incorporation of a PAEK-derived framework into interfacial polymerization. This strategy provides a relatively direct and acid-free route for constructing a thin-film composite selective layer. The resulting membrane exhibited subnanometer molecular-sieving characteristics, with an MWCO of approximately 490 Da, together with a useful balance between permeance and solute rejection. Owing to the rigid PAEK backbone and cross-linked structure, the membrane also showed good stability in the tested solvent systems. This work demonstrates a facile PAEK-based interfacial-cross-linking platform for organic solvent nanofiltration membranes.