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posted by martyb on Saturday September 03 2016, @08:44AM   Printer-friendly
from the sunlight-has-no-infrared,-right? dept.

A new polyethylene-based textile can be woven into clothing to keep people cooler:

Stanford engineers have developed a low-cost, plastic-based textile that, if woven into clothing, could cool your body far more efficiently than is possible with the natural or synthetic fabrics in clothes we wear today. Describing their work [open, DOI: 10.1126/science.aaf5471] [DX] in Science, the researchers suggest that this new family of fabrics could become the basis for garments that keep people cool in hot climates without air conditioning.

[...] This new material works by allowing the body to discharge heat in two ways that would make the wearer feel nearly 4 degrees Fahrenheit cooler than if they wore cotton clothing. The material cools by letting perspiration evaporate through the material, something ordinary fabrics already do. But the Stanford material provides a second, revolutionary cooling mechanism: allowing heat that the body emits as infrared radiation to pass through the plastic textile. [...] "Forty to 60 percent of our body heat is dissipated as infrared radiation when we are sitting in an office," said Shanhui Fan, a professor of electrical engineering who specializes in photonics, which is the study of visible and invisible light. "But until now there has been little or no research on designing the thermal radiation characteristics of textiles."

To develop their cooling textile, the Stanford researchers blended nanotechnology, photonics and chemistry to give polyethylene – the clear, clingy plastic we use as kitchen wrap – a number of characteristics desirable in clothing material: It allows thermal radiation, air and water vapor to pass right through, and it is opaque to visible light. The easiest attribute was allowing infrared radiation to pass through the material, because this is a characteristic of ordinary polyethylene food wrap. Of course, kitchen plastic is impervious to water and is see-through as well, rendering it useless as clothing.

Wait, being impervious to water and see-through renders it useless as clothing?


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  • (Score: 2) by Spamalope on Saturday September 03 2016, @09:09AM

    by Spamalope (5233) on Saturday September 03 2016, @09:09AM (#396962) Homepage

    The unanswered question I have is whether it feels nice against skin. Many synthetic clothing materials are simply less comfortable. While I'd love cooler clothing, it's not enough of an improvement if it feels like plastic.

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  • (Score: 0) by Anonymous Coward on Saturday September 03 2016, @09:13AM

    by Anonymous Coward on Saturday September 03 2016, @09:13AM (#396963)

    That success gave the researchers a single-sheet material that met their three basic criteria for a cooling fabric. To make this thin material more fabric-like, they created a three-ply version: two sheets of treated polyethylene separated by a cotton mesh for strength and thickness.

    To test the cooling potential of their three-ply construct versus a cotton fabric of comparable thickness, they placed a small swatch of each material on a surface that was as warm as bare skin and measured how much heat each material trapped.

    “Wearing anything traps some heat and makes the skin warmer,” Fan said. “If dissipating thermal radiation were our only concern, then it would be best to wear nothing.”

    The comparison showed that the cotton fabric made the skin surface 3.6 F warmer than their cooling textile. The researchers said this difference means that a person dressed in their new material might feel less inclined to turn on a fan or air conditioner.

    • (Score: 0) by Anonymous Coward on Saturday September 03 2016, @11:37AM

      by Anonymous Coward on Saturday September 03 2016, @11:37AM (#396995)

      How about a three-way comparison including a standard golf shirt? I just wore one yesterday, was outside all day and it worked great.

  • (Score: 2) by frojack on Saturday September 03 2016, @04:45PM

    by frojack (1554) on Saturday September 03 2016, @04:45PM (#397060) Journal

    Actually, my unanswered question is where was this professor in the 80s?

    This is not a exactly new concept, and you can hardly find any cotton in modern sports clothing these days.

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    • (Score: 2) by AthanasiusKircher on Saturday September 03 2016, @06:14PM

      by AthanasiusKircher (5291) on Saturday September 03 2016, @06:14PM (#397076) Journal

      Actually, my unanswered question is where was this professor in the 80s?

      This is not a exactly new concept, and you can hardly find any cotton in modern sports clothing these days.

      Except there's no actual peer-reviewed research that has proven such synthetic materials are actually better at cooling. In fact, letting sweat evaporate off bare skin is generally as effective, if not more effective, at temperature regulation than these special sports apparel that are heavily marketed at premium prices.

      The reason why cotton is less common isn't because the new materials are better at temperature regulation, but rather because they are better at wicking away moisture -- thus keeping your skin drier. Cotton is "breathable" too, but cotton fabrics tend to keep more wetness in contact with your skin (and often don't "dry" as quickly as synthetic materials), potentially leading to chafing, rashes, etc. And actually, if the clothing is not tight-fitting, the wicking effect can be counterproductive for temperature regulation, since your body is cooled through evaporation of sweat -- putting an air barrier between your skin and the clothing where the moisture will actually evaporate can reduce the effectiveness of evaporative cooling for your body itself.

      Hence, if this new material from the article actually can be scientifically proven to create a cooling effect (rather than merely a wicking effect), it IS a potentially a significant development for sports apparel.