A new type of cloth developed by researchers at the University of Waterloo can heat up when exposed to the sun thanks to innovative nanoparticles embedded in the fabric's fibre. This advance represents an innovative and environmentally friendly option for staying warm in the winter.
Wearable heated clothing typically relies on metals or ceramic heating elements to heat up and an external power source, which could pose safety risks for users.
This new cloth incorporates conductive polymer nanoparticles that can heat up to 30 degrees Celsius when exposed to sunlight. The design requires no external power and can also change colour to visually monitor temperature fluctuations.
"The magic behind the temperature-sensitive colour change lies in the combination of nanoparticles embedded in the polymer fibres," said Yuning Li, a professor in Waterloo's Department of Chemical Engineering, and part of the research team that includes Chaoxia Wang and Fangqing Ge from the College of Textile Science and Engineering at Jiangnan University in China.
"The nanoparticles are activated by sunlight, enabling the fabric to absorb heat and convert it into warmth."
The fibre is created using a scalable wet-spinning process, combining polyaniline and polydopamine nanoparticles to enhance light absorption and improve photothermal conversion. Thermoplastic polyurethane serves as the spinning matrix, while thermochromic dyes enable the reversible color-changing feature. The resultant fiber can be woven into fabric for wearable applications.
In addition to its temperature-changing capability, the Waterloo researcher's new fabric can stretch out by as much as five times its original shape and withstand as much as two-dozen washings while still maintaining its function and appearance. Its reversible colour-changing ability provides a built-in temperature monitoring feature to ensure the wearer's safety and convenience.
"We prioritized durability, ensuring the fabric could withstand repeated use and environmental exposure while maintaining its innovative properties," said Li.
The Waterloo team is exploring more cost-effective alternatives to polydopamine to make the smart fabric technology more accessible. Future developments will focus on scaling the production process and reducing costs without compromising on the fabric's innovative properties.
The fabric's potential applications include aiding in cold rescue situations and solar-powered pet clothing to help keep them comfortable when outside during the winter.
The study was recently published in the Journal of Advanced Composites and Hybrid Materials.