Permanent Anti-Fog Coatings from Molecularly Blended Hydrophilic Polymers

Technology #13561

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Image Gallery
FIGS. 5A-5D are photographs depicting results of a humid chamber test for antifog coatings. Crosslinked 10-bilayer CHI/CMC coatings on polycarbonate were exposed to at 80% humidity at 37° C. for (A) 1 second; (B) 10 seconds; (C) 20 seconds; and (D) 60 seconds. Fogged region at the bottom of the substrate is not coated.FIG. 12 is a photograph depicting a glass substrate coated at one end (to the right) with CHI/PAA-g-PEG (37% PEG) and uncoated at the other end (to the left). The glass substrate was directly exposed to hot steam after being placed in refrigerator at 4° C. for two weeks.FIGS. 13A-13C are micrographs of 15 bilayer coatings of CHI/PAA-g-PEG (37% PEG) after pencil hardness tests: (A), 2H; (B), 4H; and (C), 7H.
Categories
Inventors
Professor Robert Cohen
Department of Chemical Engineering, MIT
External Link (cohengroup.mit.edu)
Professor Michael Rubner
Department of Materials Science and Engineering, MIT
External Link (web.mit.edu)
Nurxat Nuraje
Department of Materials Science and Engineering, MIT
Albert Swiston
Department of Materials Science and Engineering, MIT
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Coatings

US Patent 8,986,848

Coatings

US Patent Pending
Publications
Durable Antifog Films from Layer-by-Layer Molecularly Blended Hydrophilic Polysaccharides
Langmuir, 2011, 27 (2), pp 782–791

Applications

This technology has applications in cases where anti-fog performance is required on various transparent or reflective surfaces, such as:

  • Optical instruments (e.g., cameras, microscopes, endoscopic instruments)
  • Eyewear (e.g., safety goggles, face shields)
  • Display screens (e.g., computer monitors, mobile device displays)
  • Windows

Problem Addressed

Fogging by moisture condensation affects many optical surfaces, such as eyeglasses and vehicle windshields, often resulting in serious hazards. This technology addresses the need for effective and durable anti-fog coatings that are compatible with a wide range of substrate materials and geometries with minimal modification to manufacturing conditions.

Technology

This technology comprises a class of durable anti-fog coatings made up of molecularly blended layers of complementary hydrophilic polymers. Thin films of these complementary polymers are alternately deposited in a layer-by-layer protocol compatible with dip, spin, or spray coating processes. The complementary polymers undergo molecular blending at layer interfaces, producing a multilayered anti-fog coating. The water-based assembly process is compatible with a wide range of substrate materials and will conform to many geometries, including parts with complex topologies. Anti-fog coatings resulting from this process exhibit good surface hardness and abrasion resistance, which can be further enhanced by inducing covalent cross-linking between layers and at the substrate-coating interface.

Advantages

  • Exceptional transparency and low haze
  • Compatibility with existing dip, spin, or spray coating processes
  • Compatibility with wide range of substrate materials and conformity to many geometries
  • High surface hardness and abrasion resistance with potential for further enhancement through cross-linking treatment
  • Excellent anti-fog performance under a variety of conditions