Flexible coaxial composite fiber based on carbon nanotube and thermochromic particles for multifunctional sensor and wearable electronics

Fibrous sensors are of interest in the fields of human activity, health monitoring and human-computer interactions due to their ability to measure human activity signals such as temperature and pressure. Although many different structures and conductive materials exist for fibrous sensors, the design and fabrication of fibrous multifunctional sensors still pose significant challenges. Here, we have designed a fibrous multifunctional sensor based on a wet-spinning three-layer coaxial fiber that exhibits a GF value of up to 45.05 in the 10-80% strain range and a sensitivity of 5.926 kPa^-1 in the 0.2-2.0 kPa pressure range, while the presence of thermochromic microcapsules allows the fibrous sensor to exhibit different colors at different temperatures: blue at 18 °C, purple at 40 °C and green at 60 °C. The multifunctional fibrous sensor can monitor human joint activity and environmental temperature changes in real time, and is easier to integrate into wearable fabrics due to its fiber shape, offering new possibilities for wearable health monitoring.