Towards Real‐Time Monitoring of Soft Robotic Systems in Endoscopic Application With Ultra‐Flexible Organic Transistor‐Based Strain Sensors

The development of sensing elements capable of direct and real-time monitoring is fundamental to the actual exploitation of soft robotic systems in real application scenarios. In this paper, the integration of an electronic strain sensor based on an ultra-flexible, all-organic field-effect transistor on a soft structure, conceived for future application as a soft robotic catheter in drug delivery, is reported. The device, entirely fabricated by means of cost-effective, large area processes, is developed over a sub-micrometrical, biocompatible substrate, with mechanical properties compatible with soft robotic production. Electrical performance of the transistor is characterized, showing the suitability of the device parameters to the envisaged application in terms of low power consumption and reproducibility. A successful integration of the ultra-flexible transistor platform into the soft robotic system is demonstrated. A thorough electromechanical characterization of the sensorized system is provided, showing a programmable sensitivity to mechanical deformation in the range 5°–30°, based on the overthreshold conditions imposed by the transistor gate voltage. The results pave the way for the effective exploitation of organic flexible electronics as a valuable solution for the development of sensorized soft robots, toward a complete observability and controllability of their actuation in operation scenarios.