Polar aprotic solvent-resistant nanofiltration membranes generated by flexible-chain binding interfacial polymerization onto PTFE substrate

The practical application of solvent-resistant nanofiltration (SRNF) still faces major challenges arising from the swelling and dissolution of substrates in organic solvents , especially in polar aprotic solvents such as dimethylformamide (DMF). To address these issues, polytetrafluoroethylene (PTFE) substrates with strong resistance to organic solvents was employed to fabricate solvent-resistant nanofiltration composite membranes . A novel reverse flexible-chain binding interfacial polymerization (rFB-IP) was proposed to fabricate polyamide (PA) selective layer onto PTFE substrate with ultra-low surface energy. Specifically, aiming at strengthening the bonding force between the substrate and selective layer, PDMS was employed as a flexible-chain binder to generate a cross-linked network on the substrate surface and within the pores to generate an interpenetrating structure with PA selective layer. The as-prepared rPA-PDMS/mPTFE composite membrane exhibited DMF permeance of 0.4 L m −2  h −1 bar −1 , 97.1% rejection to Rose Bengal (RB), a stable performance during a filtration process for 120 h, or after being immersed in DMF for 120 d. Therefore, the rFB-IP technique successfully settled the issues of the application of PTFE substrate for composite membrane fabrication, and would have outstanding potential in the development of polar aprotic SRNF membrane .