Researcher from University of Maryland have created a Fabric that can automatically regulate the heat passage so that it can keep the wearer at comfortable temperature at all times irrespective of whether the surrounding is Cool or Hot.
Have you ever thought about why you feel warm when wearing clothes at cool environments? The clothes make us feel warm by trapping infrared radiation which we commonly call as Heat. This feature of the Clothes won’t be helpful during Hot weather, as it will make you feel more hot.
So, we need Clothes that can trap the Heat or make it escape based on the external weather conditions. Previously some researchers were tried to address this by making a fabric which needs to be manually reversed to change its characteristics.
The new research is making it happen automatically without the need for the manual reversing step.
The Researchers constructed an infrared-adaptive textile composed of polymer fibers coated with carbon nanotubes. The yarn itself expanded and collapsed based on heat and humidity, which changed the spacing of the fibers. Wider fiber spacing allowed the textile to breathe but also altered the infrared emissivity of the textile. This allowed for better heat exchange under hot and wet conditions. The self-adjusting emissivity of the textile could help toward wearable thermal-management attire.
When conditions are warm and moist, such as those near a sweating body, the fabric allows infrared radiation (heat) to pass through. When conditions become cooler and drier, the fabric reduces the heat that escapes.
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, which does two things. First, it opens the pores in the fabric. This has a small cooling effect because it allows heat to escape. Second, and most importantly, it modifies the electromagnetic coupling between the carbon nanotubes in the coating.
The Researcher say that you can think of this coupling effect like the bending of a radio antenna to change the wavelength or frequency it resonates with. It’s a very simplified way to think of it, but imagine bringing two antennae close together to regulate the kind of electromagnetic wave they pick up. When the 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.
Depending on the tuning, the fabric either blocks infrared radiation or allows it to pass through. The reaction is almost instant, so before people realize they’re getting hot, the garment could already be cooling them down. On the flip side, as a body cools down, the dynamic gating mechanism works in reverse to trap in heat.