UV initiated surface grafting on polyethersulfone ultrafiltration membranes via ink-jet printing-assisted modification

An efficient graft polymerization method for modification of polymeric membranes was developed using ink-jet printing. The method for grafting was investigated by printing a zwitterionic acrylate monomer on a polyethersulfone UF membrane with subsequent UV irradiation. The successful grafting was confirmed by ATR-FTIR and XPS. This printing-assisted grafting method required 5-10X less reactant chemicals compared to known dip-coating methods, while a similar degree of grafting could be achieved. Furthermore, the grafting resulted in polymer brush morphological features, which increased with the reaction time. In addition, the membrane permeability following modification was maintained even at high degree of grafting, and rejection of PEG was only slightly affected, indicating that the grafting was predominantly on the surface and not in the pores. Static protein adsorption measurements confirmed that the modified membrane acquired low protein fouling properties, and reduced biofilm growth was observed using Pseudomonas aeruginosa as the model biofilm forming bacteria. These new tools for modification of membranes will enable optimization of surface coatings and could facilitate advances in water treatment technology.