With
the rapid advancement of wearable technology, multifunctional
sensors have garnered significant attention due to their potential
applications in environmental monitoring, health diagnostics, and
human−machine interaction. Despite their promise, challenges,
such as limited flexibility, insufficient sensitivity, and complex
production processes, have hindered their practical deployment. This
study presents the fabrication of a multifunctional flexible sensor
based on PU-supported Ti3C2T
x
/TiO2/PPy yarns for both ammonia (NH3) gas sensing and human motion detection. Key innovations include
the incorporation of polypyrrole (PPy) into the Ti3C2T
x
MXene structure and the optimization
of titanium dioxide (TiO2) content through varying hydrothermal
times, which significantly enhance the gas sensing performance. The
sensor demonstrates exceptional sensitivity and selectivity toward
NH3, with a rapid response and recovery times. Additionally,
the PU-supported composite yarns exhibit excellent mechanical flexibility
and durability, maintaining stable performance under repeated stretching
and bending cycles. In human motion detection, the sensor shows high
sensitivity and reliable performance in monitoring various physical
activities, making it highly suitable for applications in wearable
electronics. These features ensure the sensor’s applicability
in diverse settings, promoting safety and health in environments with
potential ammonia exposure and enhancing human−machine interactions
through accurate motion monitoring.