SSS 2009-03-13（在线收听）

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

If you get a scratch, your skin can heal itself. But if your car gets scratched, it stays scratched. Scientists at the University of Southern Mississippi think they may have solved that problem. They’ve developed a new material that can self-heal scratches when exposed to sunlight. They published this research in the March 13th edition of the journal Science.

The new technology first takes polyurethane—the coating on many cars. Then researchers added chitosan—that’s a key polymer in crab and shrimp shells. The final bit thrown into the mix are minute amounts of oxetane rings, with three atoms of carbon and one of oxygen.

The researchers are trying to mimic natural processes. Here’s how it works. When there’s a scratch, damaging the molecule, the oxetane ring opens. It has two reactive ends. In sunlight, chitosan breaks into two chains and generates free radicals. Then those chitosan chains link up with the reactive ends of the oxetane, filling in the scratch.

Researchers say this technique is much simpler and more cost-efficient than other attempts at self-healing. So maybe in the future, when your car gets scraped, it’ll be all healed up before you have to spend any of your hard earned scratch.

Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.