Biodegradable and flexible capacitive pressure sensor for electronic skins

In recent years, the rapid development of wearable disposable electronic devices and the increasing awareness of environmental sustainability have put forward higher and higher new requirements for the natural degradability of current electronic systems. This paper proposes a low-cost method to produce a high-performance biodegradable flexible capacitive sensor which composed of a degradable glycerol/chitosan dielectric layer with micro-protrusions and two degradable copper nanowire/chitosan electrodes. The obtained degradable sensor exhibits excellent sensing performance, with a sensitivity of 1.7 kPa −1 , fast response time (180 ms), and good repeatability. Under natural conditions, it can be completely dissolved in urban tap water containing 0.02% acetic acid and snail enzyme after 5 days, showing good natural degradability. Due to its biodegradability and excellent sensor performance, the sensor is expected to find potential applications in human health monitoring, human motion detection, disease diagnosis and artificial intelligence. (a) Schematic diagram of the sensor structure. (b) The cross-sectional SEM image of the Cu NWs/chitosan composite film. (c) The capacitance variation of the capacitance sensor made of different glycerol and chitosan mass ratios with the applied pressure. (d) SEM image of the surface of the glycerin/chitosan film. • The microstructure of the dielectric layer of the sensor is prepared by using sandpaper as a template. • The sensor has a high sensitivity of 1.7 kPa −1 in the low pressure range of 0 < P < 5 kPa. • The sensor was completely degraded after 5 days in city tap water containing 0.02% acetic acid and helicase.