China’s Zhengzhou University and Australia’s Adelaide University have jointly created a new water-repellent purple fabric that’s cooler than conventional cotton.
According to the scientists, the new fabric not only offers vibrant color but also reflects 87.6% of incoming solar radiation while keeping covered skin up to 14.4°F cooler than uncovered simulated skin during daytime testing.
The Dark Color Conundrum
Dark-colored clothing is thermal management’s worst nightmare; unlike white materials, darker materials absorb more radiation, causing their temperatures to rise under direct sunlight.
Purple falls under this category as its appearance depends on absorbing green light, one of the strongest regions of the solar spectrum. These wavelengths carry substantial solar energy, making purple fabrics, after black, one of the warmest colors you can wear in intense sunshine.
Some Materials Science Magic
The Zhengzhou-Adelaide team has now created a new purple fabric that reflects an average of 87.6% of incoming solar radiation while emitting 96.4% of mid-infrared radiation, helping it outdo cotton in the cooling department.
The fabric was created using “electrospinning,” which produced fine polymer fibers incorporating a purple metal-organic framework (MOF) called ZIF-67, and zinc oxide nanoparticles, giving the textile its vibrant color while controlling how it interacts with near-infrared and near-ultraviolet radiation.
Cooler Than White Cotton
Outdoor experiments under direct sunlight show that the purple fabric remains 7.6°F cooler than commercial white cotton and 11.2°F cooler than commercially dyed purple cotton. Furthermore, tests with simulated skin covered by the purple fabric showed it was 14.4°F cooler than uncovered simulated skin under daytime conditions.
This, along with its lightweight, flexible, stretch-resistant, water-repellent (it retained its cooling performance after 50 washing cycles), and breathable properties, makes the fabric useful for future clothing designed for outdoor workers, athletes, and others exposed to prolonged heat.
Source: https://www.thomasnet.com/