Dynamic Covalent Bond Network-Based Carbon Nanocomposite for a Self-Healing Tactile Sensor

Abstract

Capacitive tactile sensors using dielectric polymer materials as dielectric layers have been studied due to their high sensitivity and flexibility with a variety of types of materials in response to external stimuli. However, a polymer-based tactile sensor device is limited in long-term use due to a lack of mechanical stability against repeated external stimuli. In this study, a dynamic covalent polymer-based carbon composite material with high sensitivity, structural stability as well as self-healing ability was manufactured and applied as a capacitive tactile sensor dielectric layer. A polymer chain with a disulfide dynamic covalent bond was used as a composite matrix, and carbon nanofibers were applied as fillers to dramatically increase the dielectric constant of the material. The material-based capacitive tactile sensor not only had a high response signal even at a low external stimulus (0.5 kPa) but also had a high sensitivity (46.7 MPa–1) according to the intensity of the stimulus (0.5–17.5 kPa). In addition, the sensor device had a short response of less than 0.2 s and a recovery time of 0.25 s to external stimuli with a stable response signal for 5000 repetitive stimuli. Furthermore, after self-healing deformation of the dielectric layer, the sensor device showed the same level of sensitivity to external stimuli as before deformation by more than 95%.