Overview
- The peer-reviewed study published Monday in the journal Small reports the purple textile reflects about 87.6–88% of incoming sunlight and emits roughly 96.4% of mid-infrared radiation, the two optical measures that enable passive radiative cooling.
- Outdoor tests showed the material stayed up to 6.2°C (11.2°F) cooler than dyed purple cotton and about 4.2°C (7.6°F) cooler than commercial white cotton under direct sun.
- Simulated-skin experiments found the fabric reduced surface temperature by as much as 8°C (14.4°F) versus uncovered skin, outperforming both white and conventional purple cotton in daytime conditions.
- The textile is lightweight, breathable, stretch-resistant and highly water-repellent, and it retained its cooling and optical properties after 50 wash cycles and accelerated UV aging equivalent to roughly 108 days outdoors.
- Researchers say the work is a proof of concept showing that color does not preclude passive cooling and that the approach could be adapted to other colors, but wider use will require scale-up, long-term field tests and manufacturing development.