Traditional heated apparel relies on ceramic or metal heating elements powered by an external source, which can pose safety risks.
The magic behind the temperature-sensitive color change lies in the combination of nanoparticles embedded in the polymer fibers. The nanoparticles are activated by sunlight, enabling the fabric to absorb heat and convert it into warmth.
Yuning Li, Professor, Department of Chemical Engineering, University of Waterloo
The research team, which includes Chaoxia Wang and Fangqing Ge from Jiangnan University in China, used a scalable wet-spinning process to enhance light absorption and photothermal conversion. Polyaniline and polydopamine nanoparticles were combined with thermoplastic polyurethane to form the fiber matrix. Thermochromic dyes enable the fabric to change color reversibly in response to temperature changes. The resulting fibers are durable and suitable for weaving into wearable fabrics.
The fabric can stretch up to five times its original length, withstand up to 24 wash cycles without degradation, and maintain its heating and color-changing functionality. Integrated temperature monitoring enhances safety and usability.
We prioritized durability, ensuring the fabric could withstand repeated use and environmental exposure while maintaining its innovative properties.
Yuning Li, Professor, Department of Chemical Engineering, University of Waterloo
To reduce costs, the team is investigating alternatives to polydopamine and aims to scale up production while preserving the fabric's unique properties.
Potential applications include use in cold-weather rescue operations and solar-powered clothing for pets to provide warmth in winter conditions.
Journal Reference:
Ge, F., et al. (2024) Color tunable photo-thermochromic elastic fiber for flexible wearable heater. Advanced Composites and Hybrid Materials. doi.org/10.1007/s42114-024-00994-4.