一种金属聚合物的涂层能够在有紫外线照射的情况下液化，从而修复表面的划痕，一旦不再照射，就重新固化了。KH报道。

Are your car’s bumpers riddled with scars from encounters with tight parking spaces? Did the furniture movers scratch your floor? Wouldn’t it be great if those marks could just disappear? Well, thanks to the magic of chemistry, maybe such nicks will soon be nipped. Because scientists have produced a material that can actually heal itself, work published in the journal Nature. [Mark Burnworth et al., "Optically Healable Supramolecular Polymers"]

The paint on your car, the varnish on your floor, even the nylon in your panty hose are all polymers—extremely long chains of molecules held together by strong chemical bonds. But this new material isn’t like any old polymer. It’s a supramolecular polymer, made of smaller molecules held together by weak interactions with metals, which act like a kind of molecular Velcro.

When this polymeric material is torn, exposing it to an intense beam of UV radiation breaks the weak bonds in and around the tear. That disruption allows the material to flow like a liquid, which then heals the wound. When the light is switched off the polymer resolidifies, leaving the surface as good as new. Which would be good news for your bumpers. And for your teenager, who won’t have to explain the ding on your car.

—Karen Hopkin