Painting & Coating Industry (PCI) logo Powder coating summit logo
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • PRODUCTS
  • MATERIALS
  • TECHNOLOGIES
  • FINISHING
  • RESOURCES
  • EVENTS
  • DIRECTORIES
  • EMAGAZINE
  • CONTACT
cart
facebook twitter linkedin youtube
  • NEWS
  • Latest News
  • Market Trends & Reports
  • Price Alerts
  • Subscribe to eNewsletters
  • Global Top 10/ PCI 25
  • Weekly Featured Article
  • COATLE Word Game
  • PRODUCTS
  • Product News
  • Must See Products and Services
  • MATERIALS
  • Additives
  • Resins/Polymers
  • Pigments
  • Equipment
  • Distributors
  • TECHNOLOGIES
  • Adhesives
  • Architectural Coatings
  • Industrial Coatings
  • Nanotechnology
  • Powder Coatings
  • Solventborne
  • Special Purpose Coatings
  • Sustainability
  • UV Coatings
  • Waterborne
  • Waterborne
  • FINISHING
  • Finishing News
  • Finishing Technologies
  • Finishing Equipment
  • RESOURCES
  • Columns
  • Blogs
  • Coatings Supplier Handbook
  • Podcasts and Videos
  • PCI Store
  • Classifieds
  • eBooks
  • Sponsor Insights
  • White Papers
  • COATLE Word Game
  • Columns
  • Ask Joe Powder
  • Did you know?
  • Distribution Dive
  • Focus on Canada
  • Formulating With Mike
  • Innovation Insights
  • Moody's Coatings Conundrums
  • Powder Coating Perspectives
  • Target the Market
  • TiO2 Insider
  • Blogs
  • Editor's Viewpoint
  • Industry Insights
  • Podcasts and Videos
  • COAT-IT! Podcast
  • Videos/PCI TV
  • EVENTS
  • Coatings Trends & Technologies Summit
  • Paint and Coatings Academy
  • Webinars
  • Calendar of Events
  • Lifetime Achievement Award
  • DIRECTORIES
  • Buyer's Guide
  • Equipment Directory
  • Materials Directory
  • EMAGAZINE
  • Current Issue
  • eMagazine Archive
  • China Issue Archive
  • Editorial Advisory Board
  • CONTACT
  • Contact Us
  • Advertise
  • Subscribe to eMagazine
  • Subscribe to eNewsletters
Painting & Coating Industry (PCI) logo Powder coating summit logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Painting & Coating Industry (PCI) logo Powder coating summit logo
  • NEWS
    • Latest News
    • Market Trends & Reports
    • Price Alerts
    • Subscribe to eNewsletters
    • Global Top 10/ PCI 25
    • Weekly Featured Article
    • COATLE Word Game
  • PRODUCTS
    • Product News
    • Must See Products and Services
  • MATERIALS
    • Additives
    • Resins/Polymers
    • Pigments
    • Equipment
    • Distributors
  • TECHNOLOGIES
    • Adhesives
    • Architectural Coatings
    • Industrial Coatings
    • Nanotechnology
    • Powder Coatings
    • Solventborne
    • Special Purpose Coatings
    • Sustainability
    • UV Coatings
    • Waterborne
    • FINISHING
      • Finishing News
      • Finishing Technologies
      • Finishing Equipment
    • RESOURCES
      • Columns
        • Ask Joe Powder
        • Did you know?
        • Distribution Dive
        • Focus on Canada
        • Formulating With Mike
        • Innovation Insights
        • Moody's Coatings Conundrums
        • Powder Coating Perspectives
        • Target the Market
        • TiO2 Insider
      • Blogs
        • Editor's Viewpoint
        • Industry Insights
      • Coatings Supplier Handbook
      • Podcasts and Videos
        • COAT-IT! Podcast
        • Videos/PCI TV
      • PCI Store
      • Classifieds
      • eBooks
      • Sponsor Insights
      • White Papers
      • COATLE Word Game
    • EVENTS
      • Coatings Trends & Technologies Summit
      • Paint and Coatings Academy
      • Webinars
      • Calendar of Events
      • Lifetime Achievement Award
    • DIRECTORIES
      • Buyer's Guide
      • Equipment Directory
      • Materials Directory
    • EMAGAZINE
      • Current Issue
      • eMagazine Archive
      • China Issue Archive
      • Editorial Advisory Board
    • CONTACT
      • Contact Us
      • Advertise
      • Subscribe to eMagazine
      • Subscribe to eNewsletters
    Nanotechnology in CoatingsUV CoatingsFinished Products

    UV-Curable Anti-Fog Coatings

    By Guido Meijers, Atze Nijenhuis, Wenguang Li, Jens Thies
    pci0111-DSM-lg.jpg
    January 1, 2011
    This paper discusses UV-curable super-hydrophilic anti-fog coatings. 

    At certain temperature and humidity, water vapor in air condenses on solid surfaces. Because water has much higher surface energy than most solid surfaces, the condensed water usually takes the form of small droplets, which scatter light and cause haziness. Fogging is a severe problem for a lot of optical devices, such as lenses, mirrors, windshields and visors et al. Basically, there are two ways to avoid hazy water condensation. One is to control the temperature and humidity so that water condensation can not happen.

    For example, some devices use heating elements to keep the temperature high enough that water cannot condense; some devices are purged by inert gases or dry air to remove moisture. These approaches are very effective, but consume energy and they are expensive. The other approach is to use anti-fog coatings on the optical devices. Anti-fog coatings can prevent hazy water condensation and maintain the optical clarity. Obviously, this is a better approach, because anti-fog coatings are cheaper and consume no energy to operate. Considering the anti-fog mechanism, it is possible to categorize anti-fog coatings into three types.

    Type I:   The coatings remove water condensation by absorbing liquid water into the coating. Type I coatings can be saturated when moisture level is too high, and do not respond to water condensation quickly; therefore they are not very effective.

    Type II: The coatings lower the surface energy of water, and the condensed water evenly wets the surface. Usually, Type II anti-fog coatings carry extractable surfactants.(1) When water condenses on the coating surface, the surfactants dissolve into the liquid water and bring down its surface energy so that water will wet the surface evenly. Type II coatings work effectively as long as enough surfactants can be extracted into water; however, surfactants can be washed away by water, and Type II anti-fog coatings will lose their anti-fog property gradually. In addition, because it takes time for water to dissolve surfactants, Type II coatings will not respond to water condensation very quickly. When suddenly exposed to high humidity, some Type II coatings can immediately get fogged and it will take some time for them to turn clear.

    Type III: These coatings have a super-hydrophilic surface. Water has a very low contact angle, less than 5°, on superhydrophilic surfaces, and water condensed on a super-hydrophilic surface will evenly spread out very quickly. No surfactants need to be extracted from the super-hydrophilic coatings; they work instantly with little delay time. Super-hydrophilic coatings(2) perform better than the other two types of anti-fog coatings.

    In this paper, we discuss UV-curable super-hydrophilic anti-fog coatings. UV-curable anti-fog coatings(3) can be cured instantaneously. They consume less energy to produce and, more importantly, they can be produced in a roll-to-roll process at high speed.

    Experimental

    Silica nanoparticles, as a 10-15 nm particle size, 30% dispersion in methanol, were used either directly without modification or were modified by polyethylene glycol-modified silane and acrylate/methacrylate-modified silanes.

    Synthesis of Polyethylene Glycol-Modified Silane

    Table 1 Click to enlarge

    Monomethyl ether polyethylene glycol (mPEG) (Mw = 1100) was dissolved in toluene and the mixture was dried. At room temperature and under nitrogen, a molar equivalent (with respect to the mPEG) of 3-isocyantopropyl trimethoxysilane was added drop wise to the reaction mixture. A few drops of dibutyl tin dilaurate were added as a catalyst. The reaction mixture was then stirred continuously for 24 h at 50 ºC. The reaction was monitored by infrared spectroscopy; the isocyanate signal is at 2271 cm-1. Upon completion, approximately two thirds of the toluene was removed by rotary evaporation and the mPEG trimethoxysilane was precipitated into hexane and washed several times. The resulting solid was dried and characterized by 1H NMR. Reaction yields of > 90% were obtained.

    Silica Nanoparticle Surface Modification
    The surface of silica nanoparticles was functionalized with mPEG triethoxysilane and 3-(trimethoxysilyl)propyl acrylate or 3-(trimethoxysilyl)propyl methacrylate. Table 1 shows the amount of each component used in the reaction. The mixtures were stirred at room temperature overnight to finish the reaction.

    Coating Formulation

    Table 2 Click to enlarge

    Formulations were prepared by mixing modified or unmodified silicon oxide nanoparticles with reactive diluents, polyethylene glycol diacrylate (Mw = 575 g mol-1), sulfopropyl acrylate potassium salt, and a photoinitiator, 1-hydroxycyclohexyl benzophenone. The sulfopropyl acrylate potassium salt was added as a solution in water. The exact weights used for coatings are shown in Table 2. All the liquid coatings have a solid content of about 12%.

    Coatings were applied on PET or polycarbonate sheets using #16 wire wound rod. The coatings were dried for half a minute, and then cured under a 300 W per inch mercury vapor lamp at a dose of 1 J/cm2 in a nitrogen atmosphere. The thicknesses of the cured coatings were about 5 micrometers. The coated samples were characterized by cross-hatch adhesion test, pencil hardness, optical properties and steel wool scratch test.

    Results and Discussion

    Table 3 Click to enlarge

    All cured coatings have 100% adhesion on treated PET and polycarbonate substrate, 99% optical clarity and over 90% transmittance. The anti-fog properties of the coatings were tested by holding a coated substrate for 15 seconds above warm water at 50 °C. The coating performance is rated to the degree of fogging/transparency. If the coating fogs completely, having no transparency, it is rated as 1. If the coating does not fog at all, staying completely transparent, it is rated as 10. A complete description of the rating and degree of fogging is given in Table 3.

    Table 4 Click to enlarge

    Anti-fog performance of coatings is listed in Table 4. All the coatings with the sulfonate salt have perfect anti-fog properties; the coating without sulfonate salt has poor anti-fog properties. Typically, ionic groups are more hydrophilic than ethylene glycol groups, and that is probably the reason that coatings containing sulfonate salt have better performance in the fogging test.

    Because all the components are crosslinked into a polymer network, after the coatings were washed by water their anti-fog performance did not change. It also has no effect on anti-fog performance whether acrylates or methacrylates were used. However, methyacrylates polymerize much slower than acrylates. When coating E is cured in air, the coating is very tacky because of the oxygen inhibition. There is no obvious difference between coating C and coating E, when they are cured in nitrogen.

    The modification of silica nanoparticles has no effect on anti-fog performance of the coatings. Because the modified silica nanoparticles are covalently linked into the polymer network, the modified silica nanoparticles should give the coating better scratch resistance. Since silica nanoparticles without modification can already give good mechanical properties, surface modification of silica nanoparticles is not always necessary.

    Figure 1 Click to enlarge

    The coating with non-modified silica particles was applied by a roller coater on flexible PET and polycarbonate sheet. The coating was applied and cured continuously at 5 m/min in a roll-to-roll process. As shown in Table 5 and Figure 1, the coated transparent sheets have good optical and mechanical properties and uniform thickness.

    Table 5 Click to enlarge

    Anti-fog coatings were also tested at both high and low temperatures, and they worked very well between -20 ºC and 90 ºC. As shown in Figure 2, a piece of partially coated polycarbonate plate was placed on a cup of 90 ºC coffee. The plate was initially at room temperature. When it was exposed to the moisture from 90 ºC coffee, the uncoated area was immediately fogged, while the coated area always stayed clear. In the low-temperature test, the coated samples were cooled down to -20 ºC, and then were exposed to 60% humidity room temperature air. The coated area stayed clear, while the uncoated area was quickly fogged.

    Figure 2 Click to enlarge

    Conclusion

    UV-curable anti-fog coatings were developed. The coatings comprise inorganic nanoparticles and UV-curable hydrophilic materials. The coatings can prevent fogging at temperatures between -20 ºC and 90 ºC. The coatings show excellent optical clarity, good hardness and scratch resistance.

    This paper was presented at the RadTech 2010 Technology Expo and Conference, Baltimore, MD, www.radtech.org.

    KEYWORDS: coatings

    Share This Story

    Looking for a reprint of this article?
    From high-res PDFs to custom plaques, order your copy today!

    DSM Desotech, Elgin, IL
    DSM Desotech, Elgin, IL
    DSM Desotech, Elgin, IL
    DSM Desotech, Elgin, IL

    Recommended Content

    JOIN TODAY
    to unlock your recommendations.

    Already have an account? Sign In

    • PCI-0724-Global10-Feature-1440.png

      2024 Global Top 10: Top Paint and Coatings Companies

      Who ranks on top? PCI’s annual ranking of the top 10...
      Global Top 10 and PCI 25
      By: Courtney Bassett
    • PCI-0724-PCI25-Feature-1440.png

      2024 PCI 25: Top Paint and Coatings Companies

      PCI's annual ranking of the top 25 North American paint...
      Paint and Coating Market Reports
      By: Courtney Bassett
    • pci1022-Kinaltek-Lead-1170.jpg

      A Novel Pigment Production Technology

      Following an extensive R&D program that demonstrated...
      Paint and Coating Pigments
      By: Jawad Haidar and Nitin Soni
    You must login or register in order to post a comment.

    Report Abusive Comment

    Manage My Account
    • eMagazine
    • eNewsletter
    • Online Registration
    • Subscription Customer Service

    The Coatings Minute: Your Inside Look at PCInnovations

    The Coatings Minute: Your Inside Look at PCInnovations

    The Coatings Minute: Print Returns with PCI’s New Showcase Issue

    The Coatings Minute: Print Returns with PCI’s New Showcase Issue

    The Coatings Minute: Why Industry News Matters More Than Ever

    The Coatings Minute: Why Industry News Matters More Than Ever

    CTT Registration Now Open

    CTT Registration Now Open

    More Videos

    Sponsored Content

    Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the PCI audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of PCI or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

    close
    • Modern arapartment complex painted in bright colors.
      Sponsored byEPS - Engineered Polymer Solutions

      Architectural Polymers Leading the Way in Coatings Innovation

    • paint sprayer in a workshop
      Sponsored byallnex

      Enabling Performance and Compliance: allnex Introduces a New Line of VOC Exempt Solvent-Borne Resins

    Popular Stories

    No. 3 AkzoNobel

    AkzoNobel to Close Two Manufacturing Sites

    BASF SE Logo

    BASF Reportedly Eyes Exit from Coatings

    Modern living room interior with green plants, sofa and green wall

    Reimagining Architectural Paints with Plant-Based Acrylic Binders



    PCI Buyers Guide

    Submit a Request for Proposal (RFP) to suppliers of your choice with details on what you need with a click of a button

    Start your RFP

    Browse our Buyers Guide for manufacturers and distributors of all types of coatings products and much more!

    Find Suppliers

    Events

    September 3, 2025

    Coatings Trends & Technologies Summit

    The Coatings Trends & Technologies (CTT) Summit is an annual conference for both liquid and powder coatings formulators and manufacturers to discuss innovations in coatings technology. This event combines high-quality technical presentations, a resource-rich exhibit hall, and dedicated networking opportunities to connect scientific minds, foster innovation, and cultivate game-changing new ideas!

    January 1, 2030

    Webinar Sponsorship Information

    For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

    View All Submit An Event

    Poll

    Longest-running laboratory experiment

    What is the longest-running laboratory experiment?
    View Results Poll Archive

    Products

    CTT Summit Short Courses (Live 9/3/25)

    Coatings Trends & Technologies Summit is expanding its offerings with four short courses. These short courses will offer an extensive day of interactive learning.

    See More Products
    pci  webinar april 2025

    PCI CASE EBOOK

    Related Articles

    • Nanotechnology

      UV-Curable Coatings for Medical Wristbands

      See More
    • UV-Curable Concrete Coatings

      See More
    • GettyImages-147334230.jpg

      UV-Curable Coatings: Top Trends to Look Out for in 2023

      See More

    Related Products

    See More Products
    • auto-paints-and-coatings

      Automotive Paints and Coatings, 2nd Edition

    See More Products
    ×

    Keep the info flowing with our eNewsletters!

    Get the latest industry updates tailored your way.

    JOIN TODAY!
    • RESOURCES
      • Advertise
      • Contact Us
      • Directories
      • Store
      • Want More
    • SIGN UP TODAY
      • Create Account
      • eMagazine
      • eNewsletters
      • Customer Service
      • Manage Preferences
    • SERVICES
      • Marketing Services
      • Reprints
      • Market Research
      • List Rental
      • Survey & Sample
    • STAY CONNECTED
      • LinkedIn
      • Facebook
      • Youtube
      • X (Twitter)
    • PRIVACY
      • PRIVACY POLICY
      • TERMS & CONDITIONS
      • DO NOT SELL MY PERSONAL INFORMATION
      • PRIVACY REQUEST
      • ACCESSIBILITY

    Copyright ©2025. All Rights Reserved BNP Media.

    Design, CMS, Hosting & Web Development :: ePublishing

    Painting & Coating Industry (PCI) logo Powder coating summit logo
    search
    cart
    facebook twitter linkedin youtube
    • Sign In
    • Create Account
    • Sign Out
    • My Account
    Painting & Coating Industry (PCI) logo Powder coating summit logo
    • NEWS
      • Latest News
      • Market Trends & Reports
      • Price Alerts
      • Subscribe to eNewsletters
      • Global Top 10/ PCI 25
      • Weekly Featured Article
      • COATLE Word Game
    • PRODUCTS
      • Product News
      • Must See Products and Services
    • MATERIALS
      • Additives
      • Resins/Polymers
      • Pigments
      • Equipment
      • Distributors
    • TECHNOLOGIES
      • Adhesives
      • Architectural Coatings
      • Industrial Coatings
      • Nanotechnology
      • Powder Coatings
      • Solventborne
      • Special Purpose Coatings
      • Sustainability
      • UV Coatings
      • Waterborne
      • FINISHING
        • Finishing News
        • Finishing Technologies
        • Finishing Equipment
      • RESOURCES
        • Columns
          • Ask Joe Powder
          • Did you know?
          • Distribution Dive
          • Focus on Canada
          • Formulating With Mike
          • Innovation Insights
          • Moody's Coatings Conundrums
          • Powder Coating Perspectives
          • Target the Market
          • TiO2 Insider
        • Blogs
          • Editor's Viewpoint
          • Industry Insights
        • Coatings Supplier Handbook
        • Podcasts and Videos
          • COAT-IT! Podcast
          • Videos/PCI TV
        • PCI Store
        • Classifieds
        • eBooks
        • Sponsor Insights
        • White Papers
        • COATLE Word Game
      • EVENTS
        • Coatings Trends & Technologies Summit
        • Paint and Coatings Academy
        • Webinars
        • Calendar of Events
        • Lifetime Achievement Award
      • DIRECTORIES
        • Buyer's Guide
        • Equipment Directory
        • Materials Directory
      • EMAGAZINE
        • Current Issue
        • eMagazine Archive
        • China Issue Archive
        • Editorial Advisory Board
      • CONTACT
        • Contact Us
        • Advertise
        • Subscribe to eMagazine
        • Subscribe to eNewsletters