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.
【視聽版科學(xué)小組榮譽(yù)出品】
scratch
nipped
panty hose
interactions
ding
可"自愈"的"外衣"
面對眾車林立的停車場, 你的"寶馬"的保險(xiǎn)桿是不是經(jīng)常"傷痕累累"? 搬家的時(shí)候搬家工人有沒有刮壞你的地板? 要是這些刮痕能消失的話是不是很棒呢? 放心, 有我們化學(xué)魔術(shù)師, 這些小"傷痕"會迅速消失. 因?yàn)榭茖W(xué)家發(fā)明了一種可以"自愈"的材料, 研究成果發(fā)表在<自然>期刊上. [Mark Burnworth 等, "光學(xué)可自愈超分子聚合物"]
我們愛車上的油漆, 地板上的清漆, 甚至穿的尼龍絲襪都是聚合物---由強(qiáng)化學(xué)鍵組在一起的超長分子鏈. 但是這種新材料卻不是之前任何一種聚合物. 它是超分子聚合物, 由與金屬間的弱力【注1】組在一起的更小的分子構(gòu)成, 有點(diǎn)像分子組成的維可牢【注2】.
當(dāng)這種聚合物材料被劃開后,用高強(qiáng)度紫外線照射,破壞劃痕里面和周邊的弱化學(xué)鍵. 這種破壞讓材料像水一樣流動以達(dá)到"治愈傷口"的目的. 關(guān)掉紫外線后,聚合物重新固化, 表面則完好如初. 這個(gè)成果將是你的保險(xiǎn)杠的福音, 當(dāng)然, 也是那些刮傷你的車的小孩的福音.
注1: 弱力,四種基本力中第二弱的、作用距離非常短的一種力。它只作用于自旋為1/2的物質(zhì)粒子,并制約著放射性現(xiàn)象。而對諸如光子、引力子等自旋為0、1或2的粒子不起作用。
注2: 維可牢,一種尼龍搭扣,也叫“魔術(shù)貼”。