Imagine if your clothes could help keep you cool during the scorching summer heat.
Athletes, landscapers, children playing outside, or anyone spending time in the sun could all benefit from wearing cooling fabrics.
While there are already some fabrics that reflect the sun’s rays or move heat away from the body, these often require special fibers or complicated manufacturing processes.
However, researchers have now developed a new, simpler way to create cooling fabrics using a chalk-based coating that can cool the air under the fabric by up to 8 degrees Fahrenheit.
Evan D. Patamia, a graduate student at the University of Massachusetts Amherst, presented this exciting new research at the fall meeting of the American Chemical Society (ACS).
The ACS Fall 2024 meeting, held both online and in person from August 18–22, featured about 10,000 presentations on various scientific topics.
“When you step outside into the sunlight, your body and clothing start absorbing ultraviolet (UV) and near-infrared (near-IR) light from the sun, making you feel hotter,” explains Trisha L. Andrew, a chemist and materials scientist working with Patamia.
“Plus, your body is always generating heat, which adds to the warmth you feel.”
To help people stay comfortable outside, scientists have been working on creating fabrics that can deflect the sun’s rays and also release body heat—this process is called radiative cooling.
Some existing materials use synthetic particles like titanium dioxide or aluminum oxide, embedded in fibers to reflect light.
Others use organic polymers, such as polyvinylidene difluoride, but these require PFAS, which are chemicals that are difficult to break down and can be harmful to the environment.
However, these materials are hard to produce on a large scale, making them less practical for everyday use. This led Andrew to ask her research team, including Patamia and Megan K. Yee, “Can we create a fabric coating that does the same job using natural or environmentally friendly materials?”
Earlier, Andrew and her team developed a method called chemical vapor deposition (CVD) to apply durable polymer coatings to fabric. This method combines the creation and application of the coating into one step, making it easier and more environmentally friendly.
Inspired by the traditional use of limestone-based plasters to keep buildings cool in hot, sunny areas, Patamia and Yee decided to incorporate calcium carbonate—the main ingredient in limestone and chalk—into their fabric coating.
They also used barium sulfate, a material that reflects UV light and is safe for the environment. Calcium carbonate particles are good at reflecting visible and near-IR light, while barium sulfate reflects UV light.
To create the cooling fabric, the researchers treated small squares of fabric by first applying a thin layer of a polymer called poly(2-hydroxyethyl acrylate) using CVD. They then repeatedly dipped the polymer-coated fabric into solutions containing calcium or barium ions and carbonate or sulfate ions.
The result is a fabric coated with a thin, durable layer that can help keep you cool by reflecting heat and light, all while being made from simple, environmentally friendly materials.
This innovation could lead to more accessible cooling fabrics that don’t require complex manufacturing processes, making it easier for everyone to stay cool in the summer heat.
