Can This Sun-Reflecting Fabric Help Fight Climate Change?

In 2020, a graduate student from Zhejiang University in China donned a seemingly plain white vest and sat in the direct sunlight for one hour. A few feet away, researchers monitored his body temperature with infrared cameras and sensors on his skin. Half of the vest was made from ordinary cotton; the other of metafabric, a new, experimental textile made of synthetic fibers and nanoparticles that reflect light and heat. After an hour in the sun, the half of the student covered in the metafabric was nearly 5 degrees Celsius cooler than the side covered by the cotton vest, researchers reported earlier this month in Science.Metafabric is the latest development in a broader emerging field of textiles for personal heat management , clothing that can heat or cool the wearer. Researchers hope that these textiles will not only enhance personal comfort, but reduce injury and death from extreme heat . They might even help slow climate change by reducing the need for air-conditioning and heating, which accounts for about 10 percent of global electricity consumption.
“We are consuming huge amounts of power to cool our environment down,” says Yaoguang Ma, one of the senior researchers on the project and a professor of optical science and engineering at the university. “If we can have this kind of fabric made into clothes and sell those clothes to people, then we can save a lot of energy.”“Textiles are a way for people to control their environment personally,” agrees Jennifer Gerbi, the acting director of the US Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E). “It is certainly easier to change what you are wearing than to install a completely new HVAC system in your home.”

In a second trial of the vest experiment, the metafabric kept the wearer more than 3 degrees Celsius cooler than the cotton over a 30-minute period. The research team also carried out experiments with skin simulators—copper plates with heaters underneath to replicate body heat—covered in the metafabric, cotton, linen, spandex, or other common types of fabric. Across a 4-hour time span, the simulator covered by metafabric was 5 and 6.8 degrees Celsius cooler than the one covered in cotton and spandex, respectively, and 10.2 degrees cooler than an uncovered one representing bare skin. In a final experiment, the researchers compared the temperature inside toy-sized model cars covered with the kind of fabric found in a commercial vehicle cover, or the metafabric, or nothing at all. The one covered in metafabric stayed 27 degrees Celsius cooler than the other covered car, and 30 degrees cooler than the uncovered one.

Metafabric is made from a synthetic fiber coated in polytetrafluoroethylene (commonly known by the brand name Teflon) and contains tiny nanoparticles of titanium dioxide, the same metal used in sunscreen. Heat from the sun comes in different forms, including visible light (the wavelengths that humans can see), infrared, and ultraviolet (UV), which can cause sunburn and skin cancer. While titanium dioxide reflects most types of light, it absorbs UV, which is why you get hot when you wear sunscreen. Teflon, however, reflects UV wavelengths. The combination of Teflon reflecting UV and titanium dioxide reflecting other wavelengths means that metafabric reflects nearly all sunlight. “Essentially, it is a mirror,” says Ma.

Metafabric is different from the SPF-protective clothes you can buy at the store today. This clothing absorbs UV light, which protects the wearer from skin damage, but doesn’t cool them down. Other textiles that try to block sunlight are made by coating traditional textiles with metal-based or reflective dyes and chemicals, but over time, that coating wears off.