Forward-looking: Scientists at the University of Waterloo in Canada are working to commercialize a smart fabric capable of converting sunlight into heat. Ideally, the material could be made into clothing to help people in extremely frigid climates stay warm while outdoors.
Wearable heaters aren't a new idea but as Live Science highlights, existing solutions often rely on expensive metal-based materials and battery-powered heating elements that require frequent recharging – costly (if minimally) and time consuming limitations. They're also somewhat fragile and require special care when cleaning.
Key to the new smart fabric is the use of photothermally active polyaniline (PANI) and polydopamine (PDA) nanoparticles, which exhibit impressive photothermal conversion capabilities. The team, led by chemical engineer Yuning Li, also added temperature-responsive dyes that allow the fabric to change color as it heats up (Hypercolor t-shirts from the 90s, anyone?).
The end result is a soft fabric with impressive warming capabilities. In testing, the material rose from an ambient temperature of 20 degrees Celsius to 53.5 degrees Celsius in just 10 minutes when exposed to 600 watts per square meter of solar radiation. For those that prefer Fahrenheit, that's a 60.3 F swing. The fabric's color shifted, too, from red to white – a visual indicator of the temperature change. Once cooled, the fabric returns to its original color.
The material is stretchy and durable as well. It boasts an elongation capacity of up to 500 percent and can maintain its warming and color-shifting capabilities even after 25 wash cycles.
It's worth reiterating that because the fabric relies on sunlight for heat, it's not going to be of much use at night or in areas that otherwise aren't exposed to sunlight.
The team's research is available in the journal Advanced Composites and Hybrid Materials under the title, "Color tunable photo-thermochromic elastic fiber for flexible wearable heater."
Li said the next steps on the path to commercial availability include reducing costs, scaling up manufacturing, and ensuring the material won't cause any harm to the wearer.
Image credit: Chris Rosiak, The Nix Company
Smart fabric generates heat from sunlight to keep you warm in freezing temperatures
