Additional tests demonstrate chalk-coated textiles’ cooling effect in urban environments

As air temperatures stay elevated through fall months, people may still want clothes that cool them down while outside, especially if they live in cities that stay warmer than rural landscapes. Researchers who previously demonstrated a cooling fabric coating now report on additional tests of a treated polyester fabric in an article published in ACS Applied Materials & Interfaces. Fabric treated with the team’s chalk-based coating kept the air underneath up to 6°F cooler in warmer urban environments.

Researchers Evan D. Patamia, Megan K. Yee and Trisha L. Andrew created a polymer-mineral coating for commercial fabrics and presented preliminary assessments of the coating’s cooling effect at ACS Fall 2024, a meeting of the American Chemical Society, held August 18–22 in Denver.

Now, the researchers confirm that their treated polyester poplin fabric could keep a person up to 15°F cooler than untreated polyester. Additionally, they have expanded the testing environments to four outdoor urban settings, including areas with materials that absorb and emit the sun’s heat. Observations made during hot, cloudless days indicate that treated polyester cooled the air underneath the fabric regardless of the environment:

• Open grass field: averaging 6°F below ambient air temperature.
• Concrete-paved alley between buildings: averaging 3°F below ambient.
• Asphalt-paved parking lot: averaging 1°F below ambient.
• Open concrete veranda: averaging 3°F below ambient.

The researchers say their expanded results show the potential of their coated fabrics to provide energy-free cooling for pedestrians and cyclists in urban environments.