Discovering scratches on your car is a special kind of heartbreak, but in the future, they may be gone before you know it. Scientists in South Korea have developed a coating that when exposed to sunlight its scratches can repair itself in as little as 30 minutes.
This new coating contains a network of polymers based on propylene-based polyols with a hindered urea structure. Essentially, these polymers have dynamic chemical bonds that break upon stimulation and then reassemble in their original arrangement to effectively repair minor damage like scratches. In this case, the trigger is heat, which is provided by an organic photothermal dye that captures infrared light and is also embedded in the coating.
In tests on a model car, the team said the coating healed scratches in 30 minutes of midday sunlight. In theory, that means someone could open your car door with a key and the scratches would disappear before you got back.
If half an hour is too long, the team also demonstrated that the process can be sped up considerably in concentrated light. By using a magnifying glass to focus sunlight on the mark it can be fixed in less than 30 seconds.
The research team says the new coating has a number of advantages over existing self-healing coatings. Using an organic photothermal dye means it requires much less energy than the regular inorganic version, which usually requires a heat gun or a concentrated UV lamp. Others, such as Nissan’s Scratch Shield, work in milder conditions, but can take up to a week. In addition, the new coating can also repair scratches in the same location multiple times, unlike self-repairing materials that use resin bursting capsules.
Another key point is that the new coating is clear, so it does not disturb the color of the paint and can be applied using existing spray methods. While cars are the primary use case, the team says it could also be applied to other frequently scratched devices, such as cell phones or construction materials.