Dual Mode Strain–Temperature Sensor with High Stimuli Discriminability and Resolution for Smart Wearables

• Published in: Advanced functional materials 2023-04, Vol.33 (16), p.n/a
• Main Authors: Xiao, Huiyun, Li, Shengbin, He, Zidong, Wu, Yuanzhao, Gao, Zhiyi, Hu, Chao, Hu, Siqi, Wang, Shengding, Liu, Chao, Shang, Jie, Liao, Meiyong, Makarov, Denys, Liu, Yiwei, Li, Run‐Wei
• Format: Article
• Language: English
• Subjects: Ambient temperature; Body temperature; Co‐based amorphous wires; dual‐mode sensors; Heterogeneous structure; Magnetic induction; Magnetoelastic effect; magnetoelastic effects; Materials science; Prostheses; Respiration; Robotics; Sensors; Smart materials; Smart sensors; smart wearables; Strain; Temperature sensors; Textiles; Thermocouples; thermoelectricity
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202214907

Strain and temperature are important physiological parameters for health monitoring, providing access to the respiration state, movement of joints, and inflammation processes. The challenge for smart wearables is to unambiguously discriminate strain and temperature using a single sensor element assuring a high degree of sensor integration. Here, a dual‐mode sensor with two electrodes and tubular mechanically heterogeneous structure enabling simultaneous sensing of strain and temperature without cross‐talk is reported. The sensor structure consists of a thermocouple coiled around an elastic strain‐to‐magnetic induction conversion unit, revealing a giant magnetoelastic effect, and accommodating a magnetic amorphous wire. The thermocouple provides access to temperature and its coil structure allows to measure impedance changes caused by the applied strain. The dual‐mode sensor also exhibits interference‐free temperature sensing performance with high coefficient of 54.49 µV °C−1, low strain and temperature detection limits of 0.05% and 0.1 °C, respectively. The use of these sensors in smart textiles to monitor continuously breathing, body movement, body temperature, and ambient temperature is demonstrated. The developed multifunctional wearable sensor is needed for applications in early disease prevention, health monitoring, and interactive electronics as well as for smart prosthetics and intelligent soft robotics. A dual‐mode elastic sensor consisting of a tubular mechanically heterogeneous structure and featuring a hybrid detection mechanism enables real‐time measurement of strain and temperature stimuli without interference. The sensor exhibits high detection accuracy of 0.05% strain and 0.1 °C. To highlight application potential, the sensor is integrated in textile to detect breathing/human‐movement and body temperature continuously and independently, as well as ambient temperature.