Upgrading polytetrafluoroethylene hollow-fiber membranes by CFD-optimized atomic layer deposition

Polytetrafluoroethylene hollow-fiber membranes (PTFE HFMs) with attractive advantages are highly promising for many applications, but strong hydrophobicity limits their uses in aqueous systems. To address this challenge, we propose to coat ultra-thin layers of alumina by atomic layer deposition (ALD) to upgrade performances of PTFE HFMs in water treatment. However, ALD usually requires time- and labor-consuming trial-and-error to optimize operating parameters. Herein, we use computational fluid dynamics (CFD) to identify most appropriate ALD parameters for PTFE HFMs functionalization. Following the CFD-optimized parameters, the ALD-treated membranes obtain significantly improved permselectivity and fouling resistance because of the remarkable increase in wettability at negligible cost in pore sizes. Impressively, water permeability of membranes is nearly doubled while rejection is increased by ~20%, which is seldom achieved by other methods. This CFD-optimized ALD process is expected to be a universal strategy to efficiently enhance the performances of polymeric membranes.