What is this new fabric that automatically cools you down when you wear it?

Popular Science Times (Intern Wang Yuke)

Scientists predict that in the future city dwellers may be able to wear clothes made from a new type of fabric to protect against the sweltering heat.

Recently, the academic paper website of the international scientific journal Science published a paper titled "Spectral Engineering Textiles for Radiative Cooling of Urban Heat Islands", which pointed out that a three-layer fabric made of fabric, plastic and silver nanowires can make the human body feel cool.

Using a principle known as radiative cooling, the fabric selectively emits narrow bands of infrared radiation that escape Earth's atmosphere, while also blocking infrared radiation from the sun and from surrounding structures.

Molecular engineering researchers at the University of Chicago in the United States designed a three-layer fabric: the inner layer is made of ordinary clothing fabrics such as wool or cotton; the middle layer is composed of silver nanowires, which can reflect most radiation; the surface layer is made of a plastic material called polymethylpentene, which does not absorb or reflect most wavelengths of infrared light, but emits infrared light in a narrow band.

In outdoor tests, the three-layer fabric was 8.9°C cooler than regular silk and 2.3°C cooler than a material with a wide range of radiation.

When tested on the skin, the fabric was 1.8°C cooler than cotton, suggesting that this tiny temperature difference could increase the amount of time the human body can be comfortably exposed to heat by a third.

The researchers say that while it would be difficult to make this stuff into a practical textile, the work is a great demonstration of how the physics of radiative cooling could be translated into a usable material.