Crab Shells Hold the Secret to Self-Healing Paint
A breakthrough in self-healing materials, with the help of crab shells, may lead the way to cars, cell phones and other items that can fix their own scratches with a little time in the sun.
A team of researchers at the University of Southern Mississippi led by Professor Marek Urban created a coating material that repairs tiny scratches after being exposed to ultraviolet light, the team reported in the journal Science.
The researchers combined polyurethane paint and a mixture of chitosan molecules, which is found in shells of crustaceans like lobsters and crabs, and ring-shaped molecules called oxetane.
When the material is scratched - the researchers used small scratches just visible to the naked eye - the oxetane rings split. The loose ends are chemically reactive, and when the coating is exposed to sunlight, the UV light causes the chitosan molecules to react with the loose ends and seal up the split, starting at the sides of the scratch closest together. The tiny scratches healed themselves in about 30 minutes.
Although no mark is left where the scar healed, the process only works once, so if the materials were to be scratched in the exact same spot, it wouldn't heal again.
While the research doesn't yield endlessly-healing paint, a coating that can repair scratches to specific areas only once still has possible applications. Scratches to cars from stray rocks are unlikely to be in the same spot twice. And even if an item gets scratched in the same spot over and over, one free and easy fix-up is better than none at all.
Scratches - CC license by modenadude; Crab - CC license by laszlo-photo