Fabrication of anti-fouling, anti-bacterial and non-clotting PVDF membranes through one step "outside-in" interface segregation strategy.

Herein we provide an "outside-in" interface segregation strategy to modify polyvinylidene fluoride (PVDF) membranes with anti-fouling, anti-bacterial and non-clotting performances for the first time. The coagulation bath composed of DMAc, water and synthesized copolymer was used to solidify and modify membrane during phase inversion process. The functional polymer e.g. poly(vinylpyrrolidone-vinyltriethoxysilane) (PVP-VTES), poly(dimethylamino ethyl methacrylate-vinyltriethoxysilane) (PDMAEMA-VTES), poly(acrylic acid-sodium p-styrene sulfonate-vinyltriethoxysilane) (PAA-SSNa-VTES) was segregated into membrane interface from outside coagulation bath. Further hydro-thermal reaction was implemented to crosslink the functional copolymer on membrane surface. The surface chemistry (ATR-FTIR, XPS) and physical properties (SEM, contact angle, flux) confirmed surface segregation of corresponding copolymer. The membranes showed excellent anti-fouling (BSA adsorption ∼19.1 μg/cm2 ), anti-bacterial (E. coli inhibition) and non-clotting (extended APTT, PT, TT and reduced FIB) performances respectively, which is clinically significant to hemocompatible membranes. The non-clotting membrane showed unprecedented prolonged activated partial thromboplastin time (APTT ∼ 53 s when sample area is minimized to 1/32 cm2 ). The thermodynamic segregation of the copolymer driven by surface tension and membrane gelation kinetics was investigated to understand the "outside-in" interface segregation route during phase inversion. Overall, the membrane fabrication and modification can be finished simultaneously in ∼2 min, demonstrating its potential in a continuous large scale production.