Shear-pressure multimodal sensor based on flexible cylindrical pillar array and flat structured carbon nanocomposites with simple fabrication process

Measuring shear displacement and pressure simultaneously is essential for various applications, such as tactile sensors for robotic finger tips, shoe soles for gait monitoring, etc. We present a simple means of transducing shear displacement and pressure change to flexible composite sensor. The presented sensor consists of an array of cylindrical pillars standing on a flat substrate, which is composed of carbon nanotubes (CNTs) and polydimethylsiloxane. The sensing mechanism is based on changing CNT network in pillar and flat structure under shear and pressure. When a shear displacement change occurs in the pillar array, which transfers shear and pressure to flat structure in the sample, the CNT network in the sample is changed due to bending of the pillars. Under pressure, the load is transferred from the pillar array to flat structure inducing changes in relative resistance. Load transfer through this hierarchical structure enabled measurement of shear displacement and pressure up to 5 mm and 1200 kPa, respectively. Therefore, it shows great potential applications in monitoring or even recognizing various human physiological activities.