Critical surface density of zwitterionic polymer chains affect antifouling properties

Membrane technologies play an increasingly important role in producing clean drinking water. There is a great interest to design an optimal membrane surface with low-cost compound, simplicity and efficiently production. Importantly, an optimal membrane surfaces requires better permeate and prolong the membrane performance. Herein, we design distinct poly(zwitterion) modifications and investigate the effect of polymer density on the efficiency of the antifouling properties. We present combination of molecular modeling tools and experimental techniques for characterizing the effect of grafting density on antifouling properties and for providing insights into the molecular mechanisms of the antifouling process. Our results suggest that antifouling property in poly(zwitterion) is flux depended. Under dynamic flow conditions, high-density surfaces presented better antifouling performance compared with low-density surfaces by providing robust hydration layer that reduced the foulant adsorption. However, in static experimental conditions the extraction of the foulant from low-density surfaces is more favored because the poly(zwitterion) chains more fluctuate compared to high-density surfaces, thus produce less electrostatic interactions with the foulants.