Antifouling PTFE Hollow Fiber Microfiltration Membrane with a Double-Defense Mechanism

Polytetrafluorethylene (PTFE) is the preferred material for highly polluted wastewater treatment. Hydrophilic modification of the PTFE hollow fiber membrane can further enhance its filtration performance and durability. Yet, it still remains a challenge to construct a robust hydrophilic coating on the PTFE surface. Here we report a surface engineering strategy of <i>in situ</i> coating a PTFE hollow fiber membrane with poly(vinyl alcohol) (PVA) and polyion complex (PIC) double-layer (DL) hydrogels. The first PVA hydrogel layer was covalently bonded to <i>N</i>-β-(aminoethyl)-γ-aminopropyl trimethoxysilane (AEAPTS)-grafted PTFE via a glutaraldehyde (GA)-induced Schiff base reaction and aldol condensation, respectively, while the second PIC hydrogel layer was strongly anchored on PVA through hydrogen bonding and topological entanglements. The resulting PVA/PIC DL hydrogel coating exhibited favorable strength and chemical resistance. Moreover, the double-defense mechanism provided by the hydration layer and polyzwitterionic brushes endowed the membrane with durable microfiltration and antifouling performances by effectively repelling various types of pollutants.