Keeping surfaces free of contamination from fingerprints and dirt, as well as making them easier to clean, is an active field of research and technology development. Recent advances in nanotech has led to unique stay-clean and easy-to-clean surface properties.
Transparent anti-fingerprint nanocoatings find application on stainless steel surfaces, plastics and glass across a range of markets. They are particularly suitable for decorative surfaces in car interiors, households and buildings and on glass touch panels. Main applications are automotive interiors, kitchen appliances, optical lenses, and electronic displays. Over the last few years stainless steel has been increasingly applied to outer cases on important household appliances, in premium products that have the feel and sturdiness of metal. They are used in housings, facings, kitchen appliances, decorative mouldings, grips, handles or faucets and these surfaces especially sensitive to fingerprints that both tarnish their appearance and can lead to longer-term surface damage. To prevent this, protective coatings are required.
Anti-fingerprint nanocoatings reduce fingerprints to a minimum and can be simply wiped away with a dry cloth on stainless steel and glass. In the household, for example, they facilitate the cleaning of glass doors, prevent limestone deposits in shower cabins and also offer long-term protection against glass corrosion.
Market drivers
The largest market for anti-fingerprint coatings is touch screen devices. Displaybank forecasts that the total touch-screen panel market will grow to $9.65 billion and 1.35 billion units, and 800 million smart phones are expected to be touch-enabled in 2014. Touch-based technology has lead to a high demand for clean surfaces presenting a perfect, hygienic optical appearance insensitive to fingerprints. The cleaning requirements of stainless steel products are also extensive. A number of manufacturers are developing high-performance anti-fingerprint nanocoatings for plastics, metals and touch panels. According to Tianhe Chemicals Group Limited, the current global demand for anti-mar coatings is US$183 million.
Touch panels
There has been a sharp increase in the demand for touch panels used in a wide range of consumer products such as car navigation systems, smart phones and tablet PCS and the market has been expanding year by year. Such devices are routinely subjected to touch and thus commonly stained with undesirable fingerprint, skin oil, sweat and cosmetics when used. As a result there is an increasing need anti-fingerprint coatings that provide material surfaces with self-cleaning, or easy-to-clean features that improve aesthetic appearance and save maintenance time.
Steel surfaces
Ground and satin stainless steel surfaces are applied to provide a high-quality appearance. Anti-fingerprinting of stainless steel surfaces found in interior and exterior architecture, passenger elevators, public ticket machines and cover panels of white goods is desirable as in everyday use the visual appearance of these products is impaired by soiling. Cleaning and maintenance costs can be significant, especially in publicly accessed buildings.
Automotive
Anti-fingerprint nanocoatings are being developed in the automotive market due to the increase in the use of touch-based automotive human machine interfaces (HMI’s) and displays.
This need is two-fold as fingerprints not only cloud the user’s view of the display weakening the efficacy of the information being delivered, but also hinder the clarity of the display making distraction free viewing of the display less likely.
Performance benefits
Anti-fingerprint nanocoatings possess a number of benefits including:
• increase in product life (durability)
• improving safety (prevents contamination that obscures or inhibits optical performance)
• reduce the use of harsh cleaning agents (stay-clean characteristics).
It has been demonstrated that nanocoatings enhance the performance and quality of glass substrates, providing increased functionality and aesthetic value. In order to ensure the touching surfaces of electronic touchscreens and displays have an anti-fingerprint function, they must have characteristics of hydrophobicity and oleophobicity.
Beyond the aesthetics, fingerprint smudges can interfere with actual viewing under conditions such as bright sunlight. This problem is more significant when multi-layer optical coatings are applied to touch screens, usually to enhance high-ambient-light readability. Then, the presence of fingerprints can cause unattractive bluish smudges that can make the device almost unreadable. For military or medical applications, fingerprints that affect readability in high ambient light are a serious concern.
Commercial activities
According to Toray Industries, if effective anti-fingerprint coatings technology can be commercialized, a market will be created on the scale of an annual coating area of 6,000,000 m2. However, widescale adoption in touchscreen technology is still at a very early stage. Other functionalities are of greater importance such as brightness, colour saturation, and resolution.
Companies developing anti-fingerprint nanocoatings are mainly based in Germany, the United States, Japan and South Korea. Main players in the anti-fingerprint coatings market are large multi-national glass, chemicals and coatings companies. There are also a number of SMEs, mainly based in Germany with reasonable revenues in this and other nanocoating markets. Research institutions such as Northwestern University, MIT, and the Max Planck Institute in Germany are also focusing heavily on this field.
Acreo’s (www.arceo.be) Stainless Nanocoat product contains nanoparticles of glass, improving the hardness and clarity of the coating. It has been applied in anti-fingerprint stainless steel coatings. Ashai Glass (www.asahiglass.net) is developing anti-fingerprint coatings for electronics devices such as kitchen equipment, domestic appliances (hot, cold and wet) and internal architecture.
Cleancorp Nanocoatings (www.cleancorp.de) is a German company producing nanocoatings for use in hospitals, senior residences, kindergardens, the textile industry etc. Applications range from anti-graffiti for stone and mineral surfaces, corrosion protection for metals, anti- fingerprint coatings for metallic surfaces, scratch resistant, surfaces for plastics and polymeric substrates, hydro- and oleophobic, breathable coatings for stone and mineral surfaces.
CTC Nanotechnology GmbH (www.ctc-nanotechnology.com) produces a range of sol-gel coatings including temperature-resistant systems, anti-fingerprint systems and abrasion-resistant surfaces. Hitachi Chemical (www.hitachi-chem.co.jp) is developing anti-fingerprint nanocoatings for application in electronic devices. Nanogate AG (www.nanogate.de) has developed, with subsidiary Gesellschaft für Oberflächentechnik GmbH (GfO) Sicralan AP®, a transparent scratchproof coating with anti-fingerprint properties for use on stainless steel surfaces and plastics. It is particularly suitable for designer surfaces in car interiors, households and buildings.
Nissan Chemical Industries Ltd. (www.nissanchem.co.jp)
have developed a thermal cured nano for touch-screen glass that provides higher surface slip properties, higher fingerprint resistance, and durability by wet coating.
There are also a number of research faciclitites developing anti-fingerprint nanocoatings products.
Oak Ridge National Laboratory (http://www.ornl.gov/File%20Library/Main%20Nav/ORNL/Partnerships/Events/Bridging%20The%20Gap%202012/9_TransparentSuperhydrophobic_Tolga-Aytug.pdf) has developed a range of nanocoatings including superhydrophobic coatings technology for anti-fingerprint applications.
The Leibniz Institute for New Materials in Germany (www.inm-gmbh.de/en/research/nanocomposite-technology/optical-materials/) have developed easy-to-clean anti-fingerprint coatings that can be industrially scaled-up. in their Optical Materials Department.
P2i (www.p2i.com), a leading developers of waterproof nanocoatings for electronic devices is planning to expand their product offerings to include anti-scratch, anti-fingerprint and anti-microbial coatings.
