New Type of Paint Can Heal Its Own Scratches

University of Southern Mississippi (USM) scientists have just developed a new class of paint that can easily heal itself, and can also fix scratches left behind by keys, screws and other such devices. They say that, with their new polyurethane film paint, the scratch will “magically” disappear within a single hour, if the affected portion is exposed directly to sunlight. A paper detailing the new technology has already been published in the latest issue of the journal Science.

“We have developed a new macromolecule. When the polymer is damaged and exposed to sunlight, it is capable of repairing itself, and could be applied to many systems,” Marek Urban and Biswajit Ghosh, the two main authors of the recent study, explain. They add that their new mix is made almost entirely (99.99 percent) of regular polyurethane, in which they add either some four-molecule oxetane rings, or long rods of chitosan, a material closely related to chitin. The latter is the main ingredient that makes up the “mobile homes” that lobsters and crabs carry on their backs.

The new paint's mechanism of action is fairly simple – as soon as the polyurethane is scratched, its upper layers are split apart. This also breaks up some oxetane rings, and at the same time allows ultraviolet to reach the dent. Once this specific wavelength reaches the chitosan rods, they break them apart, in a process that makes the oxetane and the chitosan bind together and pull the edges of the scratch closer. Lab tests have shown that, within one hour, dents are completely healed.

In addition to working well under the influence of the Sun, the chitosan is also an environment-friendly material, on account of the fact that it's derived from a natural substance. This will be one of the main selling points of any future car or electronic device coated with the new type of paint. People are beginning to incorporate these factors into their decisions, market analysts share, so all that is made from renewable sources will become a best-seller, they think.

The fact that the technology relies on UV light is also very beneficial to consumers, because in the winter, when the Sun doesn't shine so strong, car owners can simply place an UV lamp on the spot that needs “healing,” and leave it for about an hour. This can also be done at night, so the only thing standing in the way of the new system is the cost, which has thus far not been estimated.