Thermoelectric PANI/TeNWs Fiber Based Microsensor for Passive Temperature and Active Chemical Sensing

Micrometer-scale chemical sensors serve as pivotal functional components that bridge microscopic environments and macroscopic information systems, yet integrating multiple sensing modalities within a single microscale fiber without compromising performance remains a challenge in materials design. Herein, we report a continuous wet-spinning process to fabricate multifunctional microfibers that integrate chemically responsive polyaniline (PANI) with high-Seebeck-coefficient tellurium nanowires (TeNWs). The optimized PANI/TeNWs composite fiber (60 wt.% TeNWs) achieves a Seebeck coefficient of 59.9 µV K^-1 and a power factor of 9.2 µW m^-1 K^-2, enabling passive temperature monitoring with a detection limit of 1 K, where thermal gradients directly generate the sensing signal. Simultaneously, the fiber demonstrates remarkable chemical sensing capabilities, exhibiting a Nernstian pH response (59.25 mV pH^-1) and rapid ammonia detection (0.96 s at 50 ppm). By demonstrating both passive thermoelectric transduction and active chemical sensing in a single microfiber platform, this work establishes a versatile material system that combines energy-autonomous temperature sensing with high-performance chemical detection. This integrated approach offers substantial application prospects in precision medicine and environmental safety monitoring, where miniaturized sensors with diverse functionalities are urgently needed.