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 chlorine-resistant, 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 excellent potential of providing chlorine-resistant, antifouling surfaces. This technology is very useful in the water desalination industry.
Other antifouling 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). The invented copolymer chemistry is the first-ever ultralow fouling coating developed by initiated chemical vapor deposition (iCVD), a solvent-less technique. Additionally, while fouling from membrane use can be reduced by remediation with chlorine, exposure to water with even a few parts per billion chlorine significantly degrades normal membrane performance. This polymer coating is chlorine-resistant, lowering the number of additional processing steps and, in turn, operational costs.
The inventors have developed a novel antifouling chemistry that is also chlorine-resistant. The coating derives from poly(4-vinylpyridine) (P4VP), which has been used as the precursor for antimicrobial coatings. Quaternization is performed on P4VP to obtain a positively-charged surface that is able to penetrate and degrade cell membranes of various microbes. P4VP is reacted with 1,3-propane sultone to obtain a zwitterionic chemistry with a balanced surface charge that removes killed bacteria and enhances the surface’s antimicrobial activity. Divinylbenzene (DVB) copolymerizes with 4VP and renders the copolymer resistant to the oxidation of chlorine. Ultrathin P4VP coatings are put down on commercially available TFC membranes via iCVD. Since surface tension and de-wetting are avoided, this all-dry process conforms to the geometry of the underlying substrate.
Ease of application, excellent
control and surface conformance via iCVD technique
Solvent free and room temperature deposition process is unlikely to damage delicate RO membrane
Zwitterionic copolymer film provides
ultralow biofouling surface
enhances membrane maintenance