On the Surface
By Stefan Budricks, Editor

We first broached the subject of nano-particle clear coats in this space five years ago (March 2005). Little more than a year prior, Mercedes Benz started introducing a scratch-resistant clear coat containing nano-sized ceramic particles. Kevin Farrell has over the past few months written extensively on how to deal with this and other scratch-resistant clear coats (for the conclusion of his series of articles on the subject see page 62 in this issue).

Our initial discussion took us further than mere clear coats, though. Mercedes’ researchers in Germany held out the possibility of developing self-cleaning surfaces, duplicating the so-called “lotus effect;” lotus flowers have a superfine surface that repels water and dirt without a trace. The implications this could hold for car washing is obvious.

Now comes news of progress in that direction. Not quite the lotus effect yet, but this newly developed easy-to-clean material is being hailed as “probably the world’s most versatile new technology.” Liquid glass — or in technical terms, SiO2 ultra-thin layering — is a spray-on coating that repels water and dirt; resists UV-light, heat, and acids; and is even anti-microbial. The spray produces a coating only around 100 nanometers thick (the diameter of an average human hair is 50,000 nanometers) and, as a result, is highly flexible and breathable.

The coating was invented in Turkey and further researched at the Leibniz Institute for New Materials (the INM) in Saarbrücken, Germany. Nanopool GmbH, a family-owned company in Germany, holds the patent. How it all works remains, understandably, a bit of a mystery. According to Nanopool’s United Kingdom project manager, water or ethanol (depending on the surface to be coated) is added to molecules of SiO2 extracted from quartz sand. No further nano particles, resins, or other additives are involved; the coating forms a bond “due to quantum forces.”

The product’s versatility is its greatest attraction. Because of its flexibility and breathability it can be applied to just about any surface, whether metal, wood, plastic, or fabric. Reportedly, one DIY spray application will protect a car’s finish, its upholstery, the heirloom wedding dress, or even the kitchen sink for a year or longer, obviating the need for any cleaning chemicals. The product is said to be so safe and environmentally friendly that it has found application in the agricultural and medical fields. These are no pie-in-the-sky claims. The coating is already available commercially in several EU countries and is expected to debut in British retail stores this year.

If self-cleaning surfaces sound a little farfetched, how does self-healing surfaces grab you? If you’ve followed Kevin Farrell’s series of articles, you will already know about reflow scratch-resistant clear coats, which are able to self-heal minor scratches with the application of heat. In November 2007, we reported briefly on plastic that heals itself, making it possible to keep automotive components like bumpers, dashboards, and door panels looking good for years. Following a similar approach, researchers financed by Volkswagen are developing a process to evenly distribute fluid-filled capsules into an electroplated layer on top of a surface that is subject to scratches, corrosion, or rust. If the surface is damaged, the capsules burst and a coating runs out to do the repair.

The lotus effect may not yet have been achieved, but the direction researchers are heading in is evident: surfaces that require zero maintenance. Spray-on glass takes us a step closer — painted surfaces and upholstery that require no cleaning chemicals. So-called waterless wash products already minimize the need for water. Soon: surfaces that self-repair. In combination, these developments can have a profound effect on how car washes operate in the future.