Flexible Sensors with Robust Wear-Resistant and Sensing Ability: Insight on the Microcrack Structure, Multiple Interfacial Bonds, and Possible Sensing Mechanisms

With the fast growth of wearable intelligent devices, flexible sensors with a broad strain sensing range and high sensitivity are in urgent demand. Furthermore, the sensitivity of flexible wearable electronic devices to various signal capture depends on multiple interfacial bond interactions and a microstructure. However, a flexible sensor without multiple interfacial bonds has poor mechanical properties, low sensitivity/conductivity, and single sensing function to limit commercial sensor application. In this work, the novel dip-coating technique was used to design a flexible sensor based on polyvinyl alcohol with multiple interfacial bond interactions and a microcrack structure. Interestingly, the sensor exhibits high sensitivity with gauge factor > 100, a high conductivity of 356 mS m–1, impressive thermal sensitivity (0.01071 °C–1), a large strain of 344.5%, and excellent wear-resistance and durability. Possible sensing mechanisms under multiple stimuli have been presented. Moreover, flexible sensors with multiple signal monitoring can monitor real-time full-range human body motion and physical signal collection, providing a promising strategy to develop this sensor with outstanding performance in flexible sensor and sporting applications.