In-situ assembly of polyelectrolyte via surface segregation of titanium oxide for antifouling membranes

Membrane separation technology is often challenged by serious membrane fouling. Introducing hydrophilic polyelectrolyte through facile modification methods to construct antifouling membrane surfaces remains large room to be explored. Herein, antifouling membranes with the flux recovery ratio nearly 100 % was designed via a one-step surface segregation method. Coordination and hydrogen bond interactions between hydrolyzed tetrabutyl titanate (TBT) in the casting solutions and poly(sodium-styrene-sulfonate) (PSS) in the coagulation baths were generated to assemble PSS for the first time. The PSS modified membrane surface formed a strong hydration layer to resist oil pollutants, strengthening the “fouling resistance” mechanism. On the other hand, zeta potential of the membrane surface decreased from −12.1 mV to −54.6 mV after introducing the negatively charged PSS, enhancing the “electrostatic repulsion effect” to repel negatively charged oil pollutants. The synergistic intensified “fouling resistance” and “electrostatic repulsion effect” endowed the membrane with high antifouling performance (99.5 %, 0.5 % and 0.6 % of the flux recovery ratio, total permeance decline ratio and reversible permeance decline ratio, respectively). Our work provided a facile and general strategy to develop the in-situ assemble of the polyelectrolyte on the surface with prominent antifouling performances for environmental and bioengineering applications.