A new fabric that reacts to its surrounding environment has been developed by researchers at the University of Maryland. The fabric is able to automatically regulate heat exchange in response to cold or hot conditions. When against a warm, sweaty body it allows heat to escape but when the surrounding weather is cool and dry it prevents infrared radiation from getting out. The fabric is woven from a special yarn that's been coated with a conductive material. When hot and moist the yarn compacts and activating the coating. This in turn allows infrared radiation, in the form of heat, to pass through. The results of their development was recently published in the journal Science.
“You can think of this coupling effect like the bending of a radio antenna to change the wavelength or frequency it resonates with,” says YuHang Wang, one of the papers authors and professor of chemistry and biochemistry at University of Maryland. “Imagine bringing two antennae close together to regulate the kind of electromagnetic wave they pick up. When the fabric 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.”
From the University of Maryland article: "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, opening the pores in the fabric and creating a minor cooling effect by allowing heat to escape. More importantly, it modifies the electromagnetic coupling between the carbon nanotubes in the coating."
Read more about the new fabric that reacts to its surrounding environment at University of Maryland.