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

Capacitive tactile sensors using dielectric polymer materialsasdielectric layers have been studied due to their high sensitivityand flexibility with a variety of types of materials in response toexternal stimuli. However, a polymer-based tactile sensor device islimited in long-term use due to a lack of mechanical stability againstrepeated external stimuli. In this study, a dynamic covalent polymer-basedcarbon composite material with high sensitivity, structural stabilityas well as self-healing ability was manufactured and applied as acapacitive tactile sensor dielectric layer. A polymer chain with adisulfide dynamic covalent bond was used as a composite matrix, andcarbon nanofibers were applied as fillers to dramatically increasethe dielectric constant of the material. The material-based capacitivetactile sensor not only had a high response signal even at a low externalstimulus (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 0.2s and a recovery time of 0.25 s to external stimuli with a stableresponse signal for 5000 repetitive stimuli. Furthermore, after self-healingdeformation of the dielectric layer, the sensor device showed thesame level of sensitivity to external stimuli as before deformationby more than 95%.