CANBERRA, Aug. 24 (Xinhua) — Researchers have developed a purple fabric that can stay more than 4 degrees Celsius cooler than conventional white cotton in direct sunlight, potentially opening the door to cooling clothing in a wider range of colors.
The high-tech fabric, developed by researchers from Zhengzhou University in China and Adelaide University in Australia, stayed up to 6.2 degrees Celsius cooler than commercially dyed purple cotton in outdoor testing, according to a statement released Monday by Adelaide University.
Most passive cooling fabrics are white because they reflect sunlight away from the body, while darker colors absorb more solar energy.
The researchers wanted to prove that effective cooling did not have to mean giving up color.
“Our research shows that we can have both. We can make a fabric that looks purple, but at the same time reflects most of the sun’s energy and releases heat very efficiently,” said Adelaide University Professor Ma Jun, a co-author of the study published in the journal Small.
The fabric was made using microscopic fibers containing a purple metal-organic framework and zinc oxide nanoparticles.
It reflected an average of 87.6 percent of solar radiation while emitting 96.4 percent of mid-infrared radiation, allowing heat to escape through the atmosphere towards outer space, the study showed.
Tests also showed simulated skin covered with the fabric was up to 8 degrees Celsius cooler than uncovered simulated skin during the day.
The lightweight, flexible and water-repellent fabric retained its cooling performance after 50 washing cycles and could allow water vapor, including perspiration, to pass through, the researchers said, adding the approach could potentially be adapted to other colors, creating a broader range of cooling fabrics.
