title: Surface properties and reduced biofouling of graft-copolymers that possess oppositely charged groups.
abstract: Microbial biofilms and their components present a major obstacle for ensuring the long-term effectiveness of membrane processes. Graft polymerization on membrane surfaces, in general, and grafting with oppositely charged monomers, have been shown to reduce biofouling significantly. In this study, surface forces and macromolecular properties of graft copolymers that possess oppositely charged groups were related to their potent antibiofouling behavior. Graft polymerization was performed using the negatively charged 3-sulphopropyl methacrylate (SPM) and positively charged [2-(methacryloyloxy)ethyl]-trimethylammonium (MOETMA) monomers to yield a copolymer layer on polyvinylidene fluoride (PVDF) surface. Quartz crystal microbalance with dissipation monitoring (QCM-D) technology was used to monitor the reduced adsorption of extracellular polymeric substances (EPS) extracted from a membrane bioreactor (MBR) wastewater treatment facility. Complemented measurements of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy provided evaluation of the antifouling properties of the surface. Increase in water content in grafted layer exposed to 100 mM aqueous NaCl solution was observed by QCM-D. Therefore, the grafted copolymer layer is swelled in the presence of 100 mM NaCl because of reversing of polymer self-association by counterions. Force measurements by atomic force microscopy (AFM) showed an increased repulsion between a carboxylate-modified latex (CML) particle probe and a modified PVDF surface, especially in the presence of 100 mM NaCl. The hydration and swelling of the grafted polymer layer are shown to repel EPS and reduce their adsorption. Delineating the surface properties of antifouling grafted layers may lead to the design of novel antifouling surfaces.
authors.affiliation: Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel. herzberg@bgu.ac.il
authors.forename: Moshe
authors.initials: M
authors.lastname: Herzberg
authors.forename: Amer
authors.initials: A
authors.lastname: Sweity
authors.forename: Matan
authors.initials: M
authors.lastname: Brami
authors.forename: Yair
authors.initials: Y
authors.lastname: Kaufman
authors.forename: Viatcheslav
authors.initials: V
authors.lastname: Freger
authors.forename: Gideon
authors.initials: G
authors.lastname: Oron
authors.forename: Sophia
authors.initials: S
authors.lastname: Belfer
authors.forename: Roni
authors.initials: R
authors.lastname: Kasher
mesh_terms: D018625:Microscopy, Atomic Force; D011145:Polyvinyls / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013451:Sulfonic Acids / Q000737:chemistry; D013499:Surface Properties; D005465:Fluorocarbon Polymers
chemical_list: D011145:Polyvinyls; D000644:Quaternary Ammonium Compounds; D013451:Sulfonic Acids; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers