Self-healing materials have been invented before, but they have been clunky: They usually “bleed” epoxy, which then hardens; that requires a circulatory system for the goo, or microcapsules embedded in a medium. Now, a scientist has invented a totally new approach, one in which sunlight alone can aid minor scratches in the healing process. This new material could easily be applied as a top coat option, say, on your new car.
The material is a mixture of polyurethane—paint and chitosan, a chemical that is usually found in lobster shells. Scratches cause the ring-like structure of the chitosan to split apart, but sunlight makes them reactive, so that they link again, starting from the bottom of a scratch and moving up, like a zipper. Already, the inventor, Marek Urban, thinks the material could be applied to virtually anything that requires a good scratch-proof coat, from cellphones to cars to furniture. As he’s told reporters: “Anything you can think of. If you scratch it, let it sit in the Sun for some time and it’s cured.”
There’s just one drawback: The material effectively forms an invisible “scar” when it repairs the scratch, so it can’t be scratched in the same place twice. This could limit its usefulness for handheld devices such as cellphones, which often get scratched in the same places because of the way they’re set down on surfaces or slid into pockets. But it’s still a working solution for cars, since scratches don’t usually occur in exactly the same patch on the vehicle’s body.