Biofouling refers to the undesirable attachment of organic matters, biomolecules and microbes on submerged surfaces, which diminishes the device performance. The inventors have developed a Zwitterionic polymer coating which, when applied to commercial reverse osmosis (RO) membranes, will provide excellent means to combat biofouling of these surfaces.
The invented Zwitterionic coating applied on commercially available RO membranes has enormous potential of providing ultralow biofouling surfaces.
Other anti-fouling coatings have been applied to various surfaces by processes that involve the use of harsh solvents. These solvents may cause damage to delicate substrate (such as RO membranes), cause unwanted surface tension in the deposited coatings and need additional evaporation processes for complete removal. The invented copolymer chemistry is the first-ever ultralow fouling coating developed by initiated chemical vapor deposition (iCVD), a solvent-less technique.
The inventors synthesized copolymer films – poly-4 Vinyl pyridine-co-Ethylene glycol diacrylate (p(4VP-co-EGDA)) via iCVD. Post-deposition surface treatment of the copolymner films with 3-bromoproionic Acid (3BPA) produced higher surface zwitterionic contents yielding poly carboxy betains (PCBs). PCBs have been reported to provide surfaces capable of reducing the surface adsorption of non-specific protein to ultralow level. Quaternization is performed on P4VP to obtain a neutral/near-neutral zwitterionic surface that is able to penetrate and degrade cell membranes of various microbes. EDGA is used as the cross linker to render the copolymer insoluble in water yet provide the higher hydrophilicity of the copolymer films. The functionalized (zwitterionic) copolymer film (p(4VP-co-EGDA)) has biocidal moieties (pyridinium ion) coupled with higher hydrophilicity to combat biofouling of the commercially available RO membranes.
Ease of applicability, excellent
control and confirmance to surfaces via iCVD technique
Solvent free process unlikely to
damage delicate RO membrane
Zwitterionic copolymer film provides
ultralow biofouling surface