The New Mirror “Science Fabric”

Wearers can be cooled by as much as 5degC with the new mirror Science Fabric

It’s not difficult to design clothing that keeps you warm but it is much more difficult to create clothes that keep you cool during hot summer days. Researchers have created a Science Fabric that can cool the body by almost 5 degrees Celsius. It looks similar to a T-shirt. The technology could be mass-produced and help people around the globe to protect themselves from rising temperatures due to climate change, they say.

Fashion designers often use Science Fabric which is a light-colored fabric that reflects visible light to make clothing that beats the Sun. Another method, however, reflects the Sun’s electromagnetic radiation. This includes ultraviolet (UV), and near-infrared(NIR) radiation. NIR heats the objects that absorb it, and slows down their cooling as they emit it. Our atmosphere can impede this cooling process. NIR, once it is emitted from an object is often absorbed into nearby water molecules, heating the surrounding air.

Researchers are now using mid-infrared radiation science table, a longer wavelength type of IR, to speed up the cooling process. MIR energy is not absorbed by the molecules in the air surrounding it, but instead goes into space and cools both the objects as well as their surroundings. Radiative cooling is a technique that engineers use to create roofs, plastic films and wood.

MIR is naturally emitted by the skin of humans, which is different from many clothes. A Science Fabric, which allows MIR from the body to pass through it, was developed by Stanford University researchers in 2017. It is approximately 45 micrometers thick, about one-third of the thickness of a light linen dress shirt. Some researchers questioned its durability.

Engineers Ma Yaoguang of Zhejiang University and Tao Guangming of Huazhong University of Science and Technology used a different approach to design thicker Science Fabric. Instead of letting MIR from skin pass through the Science Fabric, engineers Ma Yaoguang and Tao Guangming devised a textile that uses chemical bonds to absorb body heat and remit it into space as MIR. The Science Fabric, which measures 550 micrometers, is made of a blend of synthetic fiber and polylactic acid, with titanium dioxide nanoparticles throughout. It also reflects UV, visible and NIR light, further cooling its wearer. Tao says that even though it appears like a regular shirt it is actually a mirror.

The researchers made a snug-fitting vest from their Science Fabric, and one made of white cotton. The vest was worn by a graduate student who sat for one hour in direct sunlight in a lawn chair. The researchers found that the Science Fabric’s side was nearly 5deg C colder than the cotton side when they measured the student’s skin temperature. Science published this report today. Tao said that the student could feel the temperature change with an infrared camera.