A Bionic Gecko Suction Cup Piezoresistive Sensor with Integrated Patterned Electrodes for Limb Movement and Physiological Electrical Signal Detection

Flexible wearable electronic devices are widely used in human health management, but most wearable sensors have a single function. A portion of the sensors with multiple detection functions has complex preparation processes and high costs. In this article, we propose a bionic gecko suction cup piezoresistive sensor with integrated patterned electrodes, which has high-sensitivity piezoresistive sensing and can be used for limb movement and physiological electrical signal detection. The elastic base layer of this sensor is cast on a mold using poly(vinyl alcohol)/glycerol, and its upper surface is coated with a natural latex/carbon nanotube conductive layer to prepare a bionic gecko suction cup high-sensitivity piezoresistive structure. It has a minimum piezoresistive response of 0.5 kPa, a sensitivity of 8121.7 kPa-1 at an external pressure of 4 kPa, and a response time of 30 ms/recovery time of 20 ms. After the lower surface of the elastic substrate layer was coated with a natural latex/carbon nanotube conductive layer, a patterned metallic conductive layer with a vertical fence pattern was prepared on the conductive layer using screen printing. The patterned metal conductive layer further reduces the initial resistance of the conductive layer on the lower surface and, at the same time, increases the sensitivity of the conductive layer, which can be used for the detection of limb movement and physiological electrical signals.