Wearing one fabric that can give you warmth and cool touch function at the time when needed? How’s that possible? The researchers in Belgium have unveiled the design for a fabric that could keep a person warm when worn one way while cooling them down if worn inside out. The researchers present a theoretical design for a 20 µm thick Janus textile, named after the two-faced Roman god. The two interwoven sides of the material are composed of two different fibers – dielectric and metallic, each with very different infrared-emitting properties. The dielectric fibers can emit large amounts of radiation on one side, while on the other side, the metallic fibers have low emissivity.
To test their asymmetrical fabric, the team used a thermal model to calculate the differences between each side’s infrared transmission, reflection, and absorption properties. They discovered that if the Janus textile is worn with its dielectric fibers touching the skin, large amounts of radiation could be prevented from escaping, keeping the wearer comfortably warm in temperatures as low as 11°C. However, if the fabric is flipped inside-out, it could emit as much radiation as bare skin, keeping the wearer cool in temperatures as high as 24°C.
Although large-scale material manufacturing is not yet feasible, the researchers hope their results will inspire further research into similar fabrics. For now, Abebe’s team acknowledges that high manufacturing costs will mean that such reversible fabrics will not be appearing in our clothes any time soon. However, they hope that new designs could keep us comfortable across a wide range of temperatures with further research.
