A Zhejiang University graduate student in China donned a plain white vest in 2020 and sat for an hour in direct sunlight. Researchers positioned a few feet away monitored his body temperature using infrared cameras, sensors on his skin, and placed them near his heart. The vest was half made from regular cotton, the other half of metafabric, which is a new experimental textile that uses synthetic fibers and nanoparticles to reflect heat and light. Researchers reported in Science earlier this month that the metafabric covered half the student who was exposed to the sun for an hour and it was almost 5 degrees Celsius cooler than their cotton vest.
Metafabric, which is the latest innovation in an expanding field of textiles that are used for personal heat management (clothes that can either heat or cool the wearer), is the latest. These textiles are expected to improve personal comfort and reduce the risk of death or injury from extreme heat. They could even slow climate change by reducing global electricity consumption, which is about 10% of the world's total.
According to Yaoguang Ma (one of the leading researchers on the project, and a professor in optical science and engineering at the university), cooling the environment requires a lot of energy. This type of fabric can be made into clothes and sold to customers, which can help us save lots of energy.
According to Jennifer Gerbi (acting director of US Department of Energy's Advanced Research Projects Agency Energy (ARPAE), textiles can be used to personalize their environment. It's much easier to modify what you wear than to install a new HVAC system in your house.
The metafabric was more comfortable than the cotton for a second vest trial. It kept the wearer's temperature down by 3 degrees Celsius over a 30-minute time period. To replicate body heat covered in metafabric, cotton or linen, the research team used skin simulatorscopper plates with heaters underneath. Over a 4-hour period, the simulator with metafabric was 5.8 and 6.8 degrees Celsius colder than the one without it, respectively. The simulator with spandex and cotton was 10.2 degrees cooler than the one that had been exposed to the sun. The researchers also compared temperatures inside model cars of different sizes covered in the same fabric as commercial vehicle covers, or none at all. The covered one remained 27 degrees Celsius cooler than its counterpart, while the uncovered one stayed 30 degrees cooler.
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. The sun's heat can come in many forms. It can be visible light (the wavelengths humans can see), infrared (UV), and ultraviolet (UV). These can cause skin cancer and sunburn. Although titanium dioxide can reflect most light types, it also absorbs ultraviolet (UV), which is why sunscreen makes you feel hot. Teflon, however reflects UV wavelengths. Metafabric can reflect almost all sunlight because of the combination of Teflon reflecting UV light and titanium dioxide reflecting different wavelengths. It is basically a mirror.
Metafabric is a different product than the SPF-protective clothing you can purchase at the store. This clothing is UV-resistant and protects skin from sunburns. You can also use traditional textiles to block the sun's rays by coating them with reflective or metal-based dyes and chemicals. However, this coating eventually wears off.
