Nissan’s "Scratch Guard Coat” has been healing fine scratches on the company’s cars for a few years now, and the technology has also made its way into an iPhone case. More recent developments have produced coatings to heal more substantial scratches and scrapes using nano-capsules. Now researchers at The Netherlands’ Eindhoven University of Technology (TU/e) have developed a coating that is not only self-healing, but also promises to free car owners of the tiresome chore of washing the car.
While coatings with highly water-resistant or antibacterial properties are nothing new, their applications have been limited as they can easily lose these properties. This is because the nano-sized molecular groups that provide these properties are easily and irreversibly damaged by minor contact with the surface on which they are applied.
Researcher Catarina Esteves of the department of Chemical Engineering and Chemistry at TU/e and her colleagues claim to have solved this problem with the development of surfaces that place the functional chemical groups at the end of special “stalks” that are mixed through the coating. When the outer surface layer is removed by scratching, the “stalks” in the layer underneath re-orient themselves to the new surface to restore their function.
The researchers say this will enable the creation of highly water-resistant coatings that could be applied to cars so that superficial scratches heal themselves and water droplets roll off the car, taking dirt with them. This would mean, instead of taking the car to a car wash or getting junior to earn some pocket money, all that would be required to keep the car beaming is the occasional rain shower.
Besides doing away with some Mr. Miyagi-style Karate training, the technology could also be used in self-healing mobile phone displays, solar panels and contact lenses. The researchers say that aircraft using the self-cleaning technology would benefit from reduced fuel consumption due to the cleaner surface providing less air resistance, while ships could employ it to prevent the build up of algae on their hulls. It would also reduce the frequency with which aircraft and ships need repainting.
The researchers point out that the technology only works with superficial scratches that don’t completely penetrate the coating.
The local car wash looks set to be around for a while yet though. Esteves and her team plan to collaborate with other universities and industrial partners to develop the tech further, with the first coatings likely to be ready for production within six to eight years. She expects the prices to be comparable to coatings currently on the market.