【科学60秒】可"自愈"的"外衣"_英语听力练习mp3下载-科学-沪江听力酷

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【科学60秒】可"自愈"的"外衣"

听力简介：

Are your car’s bumpers riddled with scars from encounters with tight parking spaces? Did the furniture movers [--1--] 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 [--2--]. Because scientists have produced a material that can actually heal itself, work published in the journal Nature.

The paint on your car, the varnish on your floor, even the nylon in your [--3--] 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 [--4--] 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 [--5--] on your car.
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