Durable Flexible Conductive Fiber Based on Cross-Linking Network Tannic Acid/Polypyrrole for Wearable Thermotherapy Monitoring System.

Intelligent wearable textiles have garnered attention and advancement, particularly in the realms of thermotherapy and health monitoring. As a critical component of intelligent wearable textiles, conductive fibers are expected to have long-term stable and durable conductivity. In this work, a highly stretchable and conductive fiber based on tannic acid/polypyrrole was developed. The conductive network was formed by doping TA into PPy, resulting in enhanced stretchability of PPy on the surface of PU. TA also improves the interface interaction between PPy and PU to gain more firm attachment of PPy, which achieves high conductivity (0.89 ± 0.23 S/cm) and durability. Furthermore, the stretchable conductive fiber also exhibited intelligent responses to electricity, light, and deformation. They can serve as heat sources under the action of electricity and light (temperature was raised to 42 °C under 4 V and 54 °C under solar radiation stimuli) and can also monitor the movements of humans, making them potential applications in thermotherapy textiles and intelligent sensing equipment. A PU/TA/PPy-based all-in-one smart wearable system was fabricated using textile molding technology capable of all-weather thermal therapy and motion detection. This fiber fabrication technology and integrated system offer insights for the future development of smart wearable devices.