Polymer nanofilm with amphiphilic network for fast and precise molecular separation.

Organic solvent nanofiltration (OSN) holds substantial application potential in industries such as chemical engineering, pharmaceuticals, and energy, where the molecular design of membrane materials plays a crucial role in separation performance. In this work, a polyester/amide thin-film composite membrane featuring an amphiphilic network was fabricated via interfacial polymerization, using 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (bisAPAF) and trimesoyl chloride (TMC) as the aqueous and organic phase monomers, respectively. The incorporation of low-polarity CF3 groups into the polar polyamide network created amphiphilic nanochannels, enabling simultaneous high permeance for both polar and non-polar organic solvents. Moreover, the pore structure of the polyester/amide selective layer was precisely tailored through the modulation of NaOH additives, ensuring highly accurate molecular discrimination. The optimized membrane exhibited outstanding OSN performance, with methanol and n-hexane permeances reaching 16.6 and 8.5 L m-2 h-1 bar-1, respectively, while maintaining a molecular weight cut-off of 343 Da. Importantly, it demonstrated remarkable structural integrity and anti-swelling properties during prolonged operation. These findings provide an advanced molecular-level design strategy for constructing highly perm-selective OSN membranes with tailored transport pathways.