Antifouling Zwitterionic Coatings on Reverse Osmosis Membranes

Technology #16765

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Inventors
Professor Karen Gleason
Department of Chemical Engineering, MIT
External Link (web.mit.edu)
Hafiz Zahid Shafi
Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Saudi Arabia
Zafarullah Khan
Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Saudi Arabia
Rong Yang
Department of Chemical Engineering, MIT
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Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Development of Zwitterionic Coatings that Confer Ultra Anti-biofouling Properties to Commercial Reverse Osmosis Membranes

US Patent Pending 2016-0002489

Development of Zwitterionic Coatings that Confer Ultra Anti-biofouling Properties to Commercial Reverse Osmosis Membranes

PCT Patent Application WO 2016-007510
Publications
Surface-tethered zwitterionic ultrathin antifouling coatings on reverse osmosis membranes by initiated chemical vapor deposition
Chemistry of Materials, February 7, 2011, p. 1263-1272
Surface modification of reverse osmosis membranes with zwitterionic coating for improved resistance to fouling
Desalination, April 15, 2015, p. 93-103

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. 

Application

The invented Zwitterionic coating applied on commercially available RO membranes has enormous potential of providing ultralow biofouling surfaces.

Problem Addressed

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.

Technology

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.

Advantages 

  • 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