Wearable Flexible Temperature Sensors and Their Applications

Wearable flexible temperature sensors, as a new type of sensor technology, have the ability to monitor the surface temperature of human skin in real-time. Compared with traditional temperature sensors, wearable and flexible temperature sensors have the advantages of comfort, wearability, and strong adaptability, which can provide new solutions for medical monitoring, health monitoring, and sports training. The basic principle is based on the thermoelectric effect or thermistor effect. Specifically, temperature sensors convert thermal energy into electrical signals by measuring the temperature changes of an object. Based on the magnitude of electrical signals caused by temperature changes, the temperature of an object can be inferred. Using flexible materials as the substrate for sensors, temperature measurement is achieved by measuring the material's resistance, capacitance, or thermal conductivity. The preparation methods mainly include the selection of flexible materials, the preparation of sensing elements, and the integration of sensors. Common flexible materials include polymers, nanomaterials, and conductive fibers. This article reviews the research progress of wearable temperature sensors in recent years, including wearable optical temperature sensors, wearable temperature sensors for clinical detection, integrated wireless sensors, multi-mode force and temperature tactile sensors based on high sensitivity short channels, and other advanced temperature sensors. Finally, the challenges and future development directions of flexible wearable temperature sensors were proposed. Sensors, as one of the most important core components, will affect the functional design and future development direction of wearable devices. That's why it has been highly anticipated in recent years.