A highly flexible tactile sensor with an interlocked truncated sawtooth structure based on stretchable graphene/silver/silicone rubber composites

Tactile sensors with high flexibility have attracted great interest due to their significant potential in diverse applications including intelligent robotics, smart prosthetics, human-machine interfaces, and biomonitoring electronic devices. However, it remains a critical challenge to develop tactile sensors with both high sensitivity and flexibility. In this work, we propose a highly flexible tactile sensor with an inter-locked truncated sawtooth structure based on patterned stretchable graphene/silver/silicone rubber composites. Graphene/silicone rubber composites possess an extremely high gauge factor (similar to 13 692) and can serve as a piezoresistive sensing material. Silver/silicone rubber composites have a high conductivity (similar to 200 S cm(-1)) and a low gauge factor (similar to 15) and are used as stretchable electrodes. The interlocked truncated sawtooth structure can transform the mechanical stimuli of the sensor into tensile strains of the graphene composite, enhancing both sensitivity and flexibility. The developed tactile sensor is characterized by a high sensitivity of 0.45 V N-1 (from 0.05-1.5 N) and a low sensitivity of 0.12 V N-1 (from 1.5-2.0 N). Experimental studies have demonstrated that tactile sensors have relatively high reproducibility, fast dynamic response and both mechanical and electrical stability. These superior properties are indicative of their great potential in applications such as intelligent robotics, prosthetics, and wearable devices.