An international team of researchers from China and Australia has created a vibrant purple fabric designed to reflect solar radiation and cool human skin.
The smart textile reflects an average of 88 percent of sunlight while remaining significantly cooler than conventional cotton garments, publication Interesting Engineering reported.
Testing under direct sunlight showed the new material stayed approximately 4.2 degrees Celsius cooler than white cotton fabric and 6.2 degrees Celsius cooler than ordinary purple cotton.
In tests using a surface simulating human skin, daytime temperatures under the new textile were about 8 degrees Celsius lower than uncovered artificial skin. By comparison, white cotton lowered surface temperatures by 4.6 degrees Celsius, while standard purple cotton reduced heat by only 2.8 degrees Celsius.
Microscopic structure and passive cooling
The material relies on microscopic fibers combined with a purple metal-organic framework and zinc oxide nanoparticles. This composite structure preserves the deep purple color of the fabric while scattering incoming solar rays.
Metal-organic frameworks are porous synthetic structures composed of metal ions bound to organic molecules, frequently utilized in materials science to trap or manipulate specific chemical compounds. Zinc oxide is a widely used inorganic compound in physical sunscreens due to its ability to block broad-spectrum ultraviolet radiation.
Scientists explained that incorporating passive cooling into purple textiles is particularly challenging. Dark and vivid shades typically absorb high amounts of solar energy, causing garments to trap heat under sunny conditions.
Passive radiative cooling technology allows materials to shed heat naturally into the atmosphere without external power sources. Traditional passive cooling materials rely almost exclusively on bright white pigments to maximize solar reflectance.
Durability and practical applications
Researchers found the new fabric to be lightweight, flexible, water-repellent, and permeable to water vapor such as sweat. The material maintained its cooling properties after 50 washes and survived intense ultraviolet radiation exposure equivalent to roughly 108 days outdoors.
The key advantage of the textile is that its cooling system operates without electricity. Developers noted that the technology could eventually be used in workwear and activewear for construction workers, industrial personnel, athletes, and tourists who spend long hours outside.
While public perception often favors light-colored clothing during hot weather to reflect heat, previous research has indicated that loose-fitting black garments can cool the body even more effectively than white attire under certain conditions.
Researchers hope the technology will enable manufacturers to produce comfortable outdoor clothing in a wide range of colors rather than relying solely on white.
