A new type of fabric can sense the heat of human body and automatically release it into the external air.
Wearable devices have always made clothes smarter, but one of the most basic functions you want to achieve on a piece of clothing - keeping you warm or cool as you need to - is still frustratingly difficult to achieve. Now researchers at the University of Maryland (UMD) have developed a new material that senses the body's temperature and automatically regulates the amount of heat it absorbs or releases.
One of the easiest ways to regulate your temperature is to put on or take off your clothes. But previous research in the field of smart clothing has come up with different solutions, such as a two-sided jacket, which is cool on one side and warm on the other, so you can turn it over as needed. A high-tech attempt to solve this problem is a "robot" jacket that uses machine learning algorithms to determine a person's temperature and correspondingly open or close vents.
UMD fabric seems to be a more elegant solution. Its creators say clothes made of this material will be able to automatically respond to infrared radiation, the body's main way of releasing heat, and allow it to enter the outside air.
To do this, fibers are made of two different synthetic materials, one that absorbs water, the other that repels water, and then both materials are coated with carbon nanotubes. The idea is that when water (i.e., sweat) is absorbed by half of each fiber, it distorts the fibers and brings them closer together. This allows the fabric to cool the wearer in two ways at the same time.
First, it opens the pores of the material, allowing more heat to be released. Second, the more active cooling comes from the closer combination of carbon nanotubes. This changes the electromagnetic coupling, adjusting the nanotubes to absorb more than 35% of the infrared radiation and more heat from the wearer.
"You can think of this coupling effect as the bending of a radio antenna, changing the wavelength or frequency at which it resonates," said Wang Yuhuang, the study's co-author. "It's a very simple way of thinking, but imagine putting two antennas very close together to adjust the electromagnetic waves they receive." When the fibers get closer, the radiation they receive changes. In clothing, this means that the fabric interacts with the heat emitted by the human body.
The dynamic infrared gating technology makes the fabric the first "true two-way regulator" of human heat, the team said, and it apparently starts to work before the wearer realizes he's getting too hot.
It doesn't sound as bulky as an artificial intelligence jacket, and according to the inventor, all the materials are readily available on the market, while the carbon nanotube coating can be used in conventional dyeing processes.