Polymers (plastics) such as polyurethane and polystyrene have been the standard coating materials used in the design and development of products and equipment over the last several decades. We see and touch them numerous times on a daily basis. These coatings, while functional, have several deficiencies. Exposure to ultraviolet (UV) radiation causes photooxidative degradation, resulting in the breaking of polymer chains. We have all likely witnessed the destruction of these types of transparent coatings, often within a remarkably few years or months of application, despite all of the modern science of additives, designed to prevent the negative effects of UV light on polymers. Polymer coatings also have low resistance to abrasion, chemicals and extreme heat. In addition, these coatings have mediocre light transmission properties and often suffer from solarization and browning.
In stark contrast, the new breed of silica-based coatings represents an evolutionary advance over polymer-based offerings. Because silica is the primary material in glass, it shares the qualities of glass – superior transparency and toughness – yet has the flexibility and versatility normally associated with commonplace polymer coatings. These silica-based coatings also are highly resistant to UV degradation.
Silica-based coatings are also durable enough to be applied in thicknesses that would be far too low for any polymer to be effective. Although these coatings are glass based, their ultra-thin dimensions make them quite flexible, eliminating the main concern with glass, namely its fragility. Silica coatings have better light transmission, thermal properties, and acid resistance than traditional polymer coatings. Consistent with efforts by researchers worldwide to use eco-friendly materials, these coatings are also non-toxic and contain no fossil fuel elements, unlike their oil-based polymer counterparts. Silica coatings can also be tuned to provide a multitude of other benefits, such as abrasion resistance, omniphobicity, oleophobicity, and anti-reflectivity, to name a few.
Research and development divisions can leverage silica coatings’ ability to act as a durable and resilient host for functional materials, which when added to the surfaces of existing products, creates a variety of enhanced effects. Such functionality can be a game changer for the creation of products only feasible with this new glass-based coating. Some examples may include copper nanoparticles to reduce barnacle accumulation on nautical vessels and UV-blocking nanoparticles to mitigate radiation for both terrestrial and interstellar uses. For others, the added functionality allows for significant improvements to existing products, making them lighter, stronger and more durable.
Some companies, such as Enki technologies and DSM NV, have developed and used silica-based coatings as anti-reflective and soil-resistant coverings to improve solar photovoltaic panel efficiency. Companies such as Kristall and South Korea-based Ceko make scratch and oil-resistant, silica-based coatings offered to R&D pros within the automobile and cell phone markets, respectively. These R&D pros, in turn, use the coating to re-engineer a number of pieces used in the manufacture of these products. Other silica-based offerings also laud their hydrophobic and graffiti-resistant abilities.
U.S.-based MetaShield has created a silica-based coating that employs leading-edge nanotech principles to provide toughness and durability to a variety of substrates. Its 1 micron thick MetaShield coating meaningfully increases the mechanical strength of ordinary glass without adding size, weight or visible distortion. The company is in advanced-stage collaborations with major glass suppliers and mobile device companies to implement their glass strengthening technology in cell phones and other electronic devices.
As silica-based coatings gain acceptance, they enable research engineers and product developers worldwide to utilize materials that would otherwise not be practical due to their weak external durability. In the end, the main question is: How do plastic coatings compare with the new, nano-enabled glass coatings? Simply put, silica based coatings herald a significant disruption in the coatings market that has been dominated by waterborne polymers for the last half century.
About the Authors: Martin Ben-Dayan is CEO, and co-founder of MetaShield, along with William Bickmore who also serves as the company’s Chief Technology Officer.