surface charge modification

Membrane filtration is used in a wide array of industries to separate components in a mixture. Filtration membranes suffer from the external deposition of pollutants and microorganisms, a phenomenon known as fouling. Fouling reduces the lifetime of a membrane and therefore increases production costs. The goal of this project was to modify the surface of a hydrophobic commercial membrane with a charged coating to induce antifouling and hydrophilic properties. A zwitterionic monomer, sulfobetaine methacrylate (SBMA), was used for its steric hindrance and hydration shell formation mechanisms, which result in superior non-specific antifouling performance. When polymerizing the coating onto the surface of the commercial hydrophobic membrane, incremental amounts of SBMA monomer, SpeedCure 4265 initiator, and ethylene glycol dimethacrylate crosslinker (EGMA) were added to a 1:2 solution composed of water and isopropyl alcohol (IPA). The coated membranes were polymerized for 30 seconds using a COBRA Cure™ FX2 UV LED Curing System with a wavelength of 365 nm. An existing commercial antifouling membrane and the 9.50% SBMA, 0.50% EGMA, and 1.50% SpeedCure 4265 modified membrane exhibited superior antifouling performance compared to the other membranes. Additionally, contact angle measurements confirmed that the modification process successfully changed the surface of all membrane combinations except the 23.75% SBMA, 1.25% EGMA, and 1.50% SpeedCure 4265 membrane from hydrophobic to hydrophilic.