Nanowires-Based Stretchable Strain Sensor for Wearable Applications

Flexible, stretchable strain sensors are needed to measure physiological parameters or joint angles in wearable systems and robotics, respectively. This letter presents the stretchable strain sensor that is directly fabricated on environment-friendly Ecoflex® substrate. The sensor uses stretchable serpentine-shaped Au interconnects and Ag nanowires (NWs) as the strain-sensitive active channel. The sensor structure has been evaluated under stretching conditions that provided insights about the material integrity during device operation. The device characteristics show good linearity under low strain range (<40%), average gauge factor of 5.8, cyclic stability for more than 5000 cycles, and response time of 200 ms. Finally, the sensor was placed on human finger, as a proof of concept, and measurements were taken to understand the bending strain during finger movements and potential application in smart glove and robotics.