Polydopamine: A Simple Membrane Modification to Increase Separation Efficiency

Abstract

Recent investigations of a polymer, polydopamine, that mimics mussel adhesive protein has shown it to be an extremely versatile surface modification technique for numerous materials, including those which are traditionally considered "non-stick," such as Teflon. By using this polymer to modify various commercially available membranes, including ultrafiltration polysulfone, and nanofiltration and reverse osmosis polyamide, an increase in these membranes` surface hydrophilicty resulted in increased separation performance in the presence of harsh oil emulsion foulants. Furthermore, poly(ethylene glycol) was grafted to the polydopamine using a simple aqueous-based surface chemistry. By using a PEG ad-layer, the membranes` anti-fouling properties were further increased and, as a result, membrane efficiency increased. Protein adhesion to these membranes was also seen to decrease as a result of polydopamine deposition and PEG ad-layer addition.