科学家开发出了一种不会让你感到太热或太冷的衣服材料，这种材料可以根据你的体温自动升温或者降温。据说这种布料几乎是瞬间起作用的，在意识到自己正在变热之前，衣服就开始冷却了？
关键词：科普；致癌；生活；译文；
图片来源：Faye Levine，马里兰大学
This new fabric being developed by University of Maryland scientists YuHuang Wang and Ouyang Min is the first textile to automatically change properties to trap or release heat depending on conditions.
这种由马里兰大学科学家王玉皇和欧阳民开发的新面料是第一种根据条件自动改变性能以捕获或释放热量的纺织品。
Despite decades of innovation in fabrics with high-tech thermal properties that keep marathon runners cool or alpine hikers warm, there has never been a material that changes its insulating properties in response to the environment. Until now. University of Maryland researchers have created a fabric that can automatically regulate the amount of heat that passes through it. When conditions are warm and moist, such as those near a sweating body, the fabric allows infrared radiation (heat) to pass through. When conditions become cooler and drier, the fabric reduces the heat that escapes. The development was reported in the February 8, 2019 issue of the journal Science.
尽管几十年来，在高科技热性能面料上探索不断，例如可以使马拉松运动员保持凉爽，使高山徒步旅行者保持温暖的功能服装，但从来没有一种材料能根据环境变化改变其绝缘性能。直到现在，马里兰大学的研究人员发明了一种能够自动调节通过它的热量的织物。在温暖潮湿的环境下，比如身体出汗时，织物允许红外辐射(热量)通过。当环境变得凉爽干燥时，织物会减少散发的热量。这一发现发表在2019年2月8日的《科学》杂志上。
The researchers created the fabric from specially engineered yarn coated with a conductive metal. Under hot, humid conditions, the strands of yarn compact and activate the coating, which changes the way the fabric interacts with infrared radiation. They refer to the action as "gating" of infrared radiation, which acts as a tunable blind to transmit or block heat.
研究人员用涂有导电金属的特殊工程纱线制作了这种面料。在湿热条件下，纱线会收缩并激活涂层，从而改变织物与红外辐射相互作用的方式。研究人员将这种行为称为红外辐射的“门控”，它作为一个可调谐的盲板来传输或阻挡热量。
"This is the first technology that allows us to dynamically gate infrared radiation," said YuHuang Wang, a professor of chemistry and biochemistry at UMD and one of the paper's corresponding authors who directed the studies.
“这是第一项允许我们动态屏蔽红外辐射的技术，”王玉皇说，他是纽约大学化学和生物化学教授，作为这篇论文的通讯作者之一，指导了这项研究。
The base yarn for this new textile is created with fibers made of two different synthetic materials—one absorbs water and the other repels it. The strands are coated with carbon nanotubes, a special class of lightweight, carbon-based, conductive metal. Because materials in the fibers both resist and absorb water, the fibers warp when exposed to humidity such as that surrounding a sweating body. That distortion brings the strands of yarn closer together, which does two things. First, it opens the pores in the fabric. This has a small cooling effect because it allows heat to escape. Second, and most importantly, it modifies the electromagnetic coupling between the carbon nanotubes in the coating.
这种新型纺织品的底纱是由两种不同的合成材料制成的纤维构成 - 一种吸水，另一种防水。这些纱线被“碳纳米管”所覆盖，碳纳米管是一种特殊的轻质碳基导电金属。因为纤维中的材料既能防水又能吸收水分，所以当纤维暴露在潮湿的环境中，比如身体出汗时，纤维就会发生翘曲。这种变形使纱线更紧密地结合在一起，这有两个作用。首先，它打开织物中的毛孔。这具有冷却效果，因为它允许热量逸出。其次，也是最重要的一点，它改变了涂层中碳纳米管之间的电磁耦合。
图片来源：Faye Levine，马里兰大学
University of Maryland Chemistry and Biochemistry Professor YuHuang Wang (left) and Physics Professor Min Ouyang hold a swatch of their new fabric that can automatically adjust its insulating properties to warm or cool a human body. Credit: Faye Levine, University of Maryland"
马里兰大学化学与生物化学教授王玉皇（左）和物理学教授欧阳民拿着他们新面料的样品，可以自动调节其绝缘性能，以实现保暖或降温。
You can think of this coupling effect like the bending of a radio antenna to change the wavelength or frequency it resonates with," Wang said. "It's a very simplified way to think of it, but imagine bringing two antennae close together to regulate the kind of electromagnetic wave they pick up. When the fibers are brought closer together, the radiation they interact with changes. In clothing, that means the fabric interacts with the heat radiating from the human body."
“你可以将这种耦合效应想象成无线电天线的弯曲，从而改变与之共振的波长或频率，”王玉皇说。“这是一种非常简单的思考方式，但想象一下将两个天线靠得很近来调节它们接收到的电磁波。当纤维靠的更近时，它们所受到的辐射会发生变化。在服装中，这意味着面料与人体散发的热量相互作用。”
Depending on the tuning, the fabric either blocks infrared radiation or allows it to pass through. The reaction is almost instant, so before people realize they're getting hot, the garment could already be cooling them down. On the flip side, as a body cools down, the dynamic gating mechanism works in reverse to trap in heat.
根据调节的不同，这种织物要么阻挡红外辐射，要么允许其通过。这种反应几乎是瞬间产生的，所以在人们意识到自己变热之前，衣服就已经在给他们降温了。另一方面，当身体冷却时，动态门机制反向工作，以捕获热量。
"The human body is a perfect radiator. It gives off heat quickly," said Min Ouyang, a professor of physics at UMD and the paper's other corresponding author. "For all of history, the only way to regulate the radiator has been to take clothes off or put clothes on. But this fabric is a true bidirectional regulator."
“人体是一个完美的散热器。它可以快速释放热量，”华盛顿大学物理学教授，该论文的另一位通讯作者欧阳闵说。“纵观历史，调节人体散热的唯一方法就是脱掉或穿上衣服。但这种面料是一种真正的双向调节器。”
According to the Science paper, this is first textile shown to be able to regulate heat exchange with the environment.
根据《科学》杂志的这篇论文，首次证明纺织品能够调节与环境的热交换。
"This pioneering work provides an exciting new switchable characteristic for comfort-adjusting clothing," said Ray Baughman, a professor of chemistry at the University of Texas who was not involved in the study. "Textiles were known that increase porosity in response to sweat or increasing temperature, as well as textiles that transmit the infrared radiation associated with body temperatures. However, no one before had found a way to switch both the porosity and infrared transparency of a textile so as to provide increased comfort in response to environmental conditions."
“这项开拓性的研究为调节舒适的衣服提供了一个令人兴奋的新特性，”德克萨斯大学的化学教授Ray Baughman说，他没有参与这项研究。“众所周知，纺织品会随着汗液或温度的升高而增加孔隙度，同时纺织品也会传输与体温相关的红外辐射。但是，之前没有人找到一种方法来改变纺织品的孔隙度和红外透明度。从而根据环境条件提供更多的舒适性。”
More work is needed before the fabric can be commercialized, but according to the researchers, materials used for the base fiber are readily available and the carbon coating can be easily added during standard dying process.
在这种面料商业化之前还需要做更多的工作，但据研究人员称，用于基纤维的材料很容易获得，而且在标准染色过程中很容易添加碳涂层。
"I think it's very exciting to be able to apply this gating phenomenon to the development of a textile that has the ability to improve the functionality of clothing and other fabrics," Ouyang said.
“我认为，能够将这种门控现象应用到一种能够改善服装和其他面料功能的纺织品的开发中，非常令人兴奋，”欧阳说。
(责任编辑：李露)
