Yi Cui's team at Stanford University in the US has developed a new type of fabric with more efficient heat dissipation properties than any current natural or synthetic fabric. Their work, published in the journal Science on Sept. 2, suggests that the new fabric could be used to process clothing that would keep the wearer cool and comfortable in hot weather, even without air conditioning.
All objects, including our bodies, dissipate heat in the form of infrared radiation. Infrared is a type of long-wavelength light invisible to the naked eye. Night vision goggles, which can see people in the dark, capture this infrared radiation.
As we all know, clothing keeps us warm by confining our radiated heat around our bodies. Therefore, wearing any kind of clothing limits the loss of body heat.There are some fabrics on the market that claim to reduce body surface temperature by effectively increasing the evaporation of sweat, but the new heat dissipation materials do more than that. The new material adds an unprecedented mechanism: it boosts the body's heat dissipation by sending out more of the body's infrared radiation.
"When we sit in an office, 40 to 60 percent of our body heat is emitted in the form of infrared radiation," says Shanhui Fan, a professor at Stanford University's School of Electrical Engineering who specializes in photonics. However, very little research has been done on how to design the thermal radiation transmission characteristics of textiles."
This new heat dissipation material is similar to our daily kitchen plastic wrap - polyethylene plastic. Polyethylene material has an important property, that is, allowing infrared radiation through, but is impervious to water, air, and transparent, can not be used as clothing material. Researchers at Stanford University used a combination of nanotechnology, photonics and chemistry to improve polyethylene to give it a range of properties that can be used in heat-dissipating fabrics: it allows heat radiation to pass through, it breathes water, and it is opaque to visible light.
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