Ionic Gel Based Multifunctional Sensor for Body Temperature Monitoring and Joint Motion Detection

Abstract

Flexible temperature and strain sensors are key components of wearable devices for healthcare monitoring. Currently, the insufficient precision, undesirable mechanical properties, and the cross interference between different external stimuli are still bottleneck problems for flexible sensors especially in body temperature and human motion monitoring. Herein, an ionic gel based on ionic liquids (ILs) and commercial thermoplastic polyurethane (TPU) fiber is fabricated via a feasible and scalable immersion method for temperature and strain multifunctional sensing. Wearable sensor based on ionic gel exhibits high temperature sensitivity (2.73% ◦ C −1 ) and sufficient resolution (0.1 ◦ C) in the skin temperature range. Meanwhile, the sensor exhibits linear and stable strain sensing performance and has the ability to respond to tiny strains. More importantly, the multifunctional fiber‐like sensor is easy to integrate with traditional textile, which is beneficial to solve the wearability problems such as discomfort and impermeability in practical applications. Notably, the stimulus caused by strain can be almost avoided by sewing smart fibers into S‐shape during the temperature monitoring, which helps decouple the temperature and strain signals. As prepared intelligent textiles can accurately capture small fluctuations in temperature and detect the action amplitude of the human body, which is important for disease prediction and rehabilitation training of patients.