27 May 2019 |
World innovation news |
Materials & Manufacturing
The First Fabric that can Protect from Cold and Heat
A number of textile technologies have revolutionized the clothing industry through their unique thermal properties. In this category, we find fabrics made of phase-changing materials for clothing with insulating and warming abilities. However, none of the current technologies can protect against all temperature variations.
A team led by YuHuang Wang, professor of biochemistry at the University of Maryland (UMD) in the United States, has created a fabric that modifies its function depending on the user’s need. It can protect both from cold and from heat. In a recently published article, the researchers stated that this is the first textile capable of modifying its properties to block or release heat depending on external temperatures. Indeed, in hot and humid weather, the fabric lets through infrared radiation emitted by the body. In cold and dry weather, the textile retains this body heat.
Textile Composition and Operation
The fabric is made from threads with nanoscale properties, composed of cellulose triacetate-based fibers. The fibers are also coated with carbon nanotubes, a light conductive metal.
Before discussing how the fabric reacts to different temperatures, it is important to understand the body’s thermal changes in response to the environment. The average body temperature is 37oC. In an ambient environment, humans emit infrared radiation of about 10 μm. As shown in this video, when temperatures drop, the hypothalamus, our internal thermostat, activates a system that brings heat to the skin.
The new textile also has a system that reacts to ambient conditions. The fibers are composed of a hydrophobic and a hydrophilic compound. When exposed to moisture like sweat, the fibers distort, modifying the electromagnetic coupling between the overlying surface of carbon nanotubes, and changing the way the textile reacts to infrared radiation. The textile retains or releases infrared like a barrier, hence the term “gating” used by researchers.
This is a simulation of the fibres reacting to temperature changes.
According to the researchers, the technology requires further work before being marketed.
The study entitled “Dynamic gating of infrared radiation in a textile”, published in Science on February 8, 2019, was co-authored by researchers at the Department of Chemistry and Biochemistry, Department of Physics and Center for Nanophysics and Advanced Materials, and Maryland NanoCenter, UMD.