TECH SPECIAL ....Now, a dress for all seasons

TECH SPECIAL Now, a dress for all seasons

It’ll Automatically Warm You Up, Or Cool You Down

Washington:

Scientists have created a fabric that can automatically regulate the amount of heat that passes through it, helping a person stay cool or warm depending on the weather condition. When conditions are warm and moist, the fabric allows heat to pass through. When it’s cool and dry, the fabric reduces the heat that escapes, researchers said.

Researchers from University of Maryland created the fabric from specially engineered yarn coated with a conductive metal.

This is the first textile shown to be able to regulate heat exchange with the environment, according to the study published in ‘Science’.

Under hot, humid conditions, the strands of yarn compact and activate the coating, which changes the way the fabric interacts with infrared radiation. They refer to this as “gating” of infrared radiation, which acts as a tunable blind to transmit or block heat.

“This is the first technology that allows us to dynamically gate infrared rays,” said YuHuang Wang, a professor at Maryland.

The base yarn for this new textile is created with fibres 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, carbonbased, conductive metal. Since materials in the fibres both resist and absorb water, the fibres warp when exposed to humidity such as that surrounding a sweating body.

That distortion brings the strands of yarn closer together, which opens the pores in the fabric. This has a small cooling effect as it allows heat to escape.

Depending on the tuning, the fabric either blocks infrared radiation or allows it to pass through. The reaction is almost instant, so before people realise they’re getting hot, the garment could already be cooling them down. On the flip side, as a body cools down, the mechanism works reverse to trap heat. “The human body is a perfect radiator. It gives off heat quickly,” said Min Ouyang, another professor at the university.

PTI

TOI11FEB19