A protective coating for surfaces that can self-repair itself in the event of even deep damage such as scratches and grooves, simply by exposure to sunlight for a relatively short period, up to just 30 minutes. It was developed by researchers at the Korea Research Institute of Chemical Technology, managing to create a material that is both resistant, but also able to self-repair quickly, two characteristics that until now have been mostly mutually exclusive. In addition, the material developed by the researchers is completely transparent, thus leaving intact the appearance of the surface it protects. It goes without saying that such a coating would find its ideal application in the protection of car bodies.
The result was obtained with a particular combination of polymers with dynamic chemical bonds, that is, capable of breaking due to an external stimulus (the action that scratches the surface) and of reassembling themselves in their original form. This occurs through the heat that is absorbed by the sunlight thanks to a particular organic photothermal dye that is particularly sensitive to the infrared component of sunlight. When infrared radiation is absorbed by the dye, the surface of the coating rises allowing the chemical bonds of the polymer to reform where they have been damaged.
Researchers demonstrated how the coating works on a toy model car, showing how focusing sunlight with a lens can speed up the process, bringing the repair time to a few tens of seconds. With the midday sun, scratches heal themselves in about 30 minutes. The new coating, unlike some commercial solutions on the market today, can repair scratches that have formed several times even in the same spot. In addition to the automotive sector, the new coating could also find application in the protection of smartphone and tablet screens.