#286Highlight Incorrect WordsAcademic,CoreMedium

Self-healed Scratches

Official Question Material
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Official Audio Prompt

If you get a scratch, your skin can heal itself. But if your car gets scratched, it stays scratched. Scientists at the [University:College] of Southern [Mississippi:Melbourne] think they may have solved that problem. They've developed a new [material:tutorial] that can self-heal [scratches:marks] when exposed to sunlight. They published this [research:study] in the March 13th issue 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:harming] 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:easier] 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.

Sample Answer & Audio Transcript

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 issue 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.
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