When the condition is warm or moist like sweating body in summer, the fabric allows the infrared radiations or radiant heat to pass through. When conditions become cooler and drier, the fabric reduces the heat that escapes, according to the study.
The base of the fabric is a yarn of two different synthetic materials, one of which absorbs water and the other repels it.
The researchers from University of Maryland in the United States created the fabric from specially engineered yarn coated with a conductive metal. Because these changes are triggered by the conditions in which the fabric resides, the user automatically benefits from the temperature regulation without having to do anything. The strands are coated with carbon nanotubes, a special class of lightweight, carbon-based, conductive metal.
"In clothing, that means the fabric interacts with the heat radiating from the human body", he added. The idea is, when water (i.e. sweat) gets absorbed by half of each fiber, it distorts the fibers so they come closer together.
It also modifies the electromagnetic coupling between the carbon nanotubes in the coating, researchers said.
This is the first technology that allows us to dynamically gate [regulate] infrared radiation, said YuHuang Wang, a UMD professor of chemistry and biochemistry and one of the papers corresponding authors. In humid and hot circumstances, the threads of fabric initiate the coating after getting compact.
"When the fibres are brought closer together, the radiation they interact with changes". The journal Science published this discovery in their 8 Feb' 2019 issue.
Depending on the tuning of the nanotubes, infrared radiation is either blocked or allowed to pass through - and this happens nearly instantly. Incredibly, the effect is almost instant, so the fabric will already be cooling people down or warming them up even before they realize that they're warm or cold. On the flip side, as a body cools down, the dynamic gating mechanism works in reverse to trap in heat. "It gives off heat quickly", said co-lead author Professor Min Ouyang, a researcher at the University of Maryland.
The scientists hope their work will lead to what they call "comfort-adjusting clothing", though they say more work is needed before stores sell shirts that react to San Francisco's maddening weather. However, this is the first demonstration of a material that can change both porosity and infrared transparency, thereby providing more comfort in response to environmental conditions. The content of this article does not necessarily reflect the views of this organization.