Fully 3D-Printed Soft Capacitive Sensor of High Toughness and Large Measurement Range

Adv Sci (Weinh). 2025 Jan 7:e2410284. doi: 10.1002/advs.202410284. Online ahead of print.

Abstract

Soft capacitive sensors are widely utilized in wearable devices, flexible electronics, and soft robotics due to their high sensitivity. However, they may suffer delamination and/or debonding due to their low interfacial toughness. In addition, they usually exhibit a small measurement range resulting from their limited stiffness variation range. In this paper, soft silicone-based capacitive sensors are developed by using a customized multimaterial 3D printer. By curing silicone materials simultaneously, the continuous conductive and dielectric layers achieve a substantial interfacial toughness of 1036 J·m-2. The sensor with tilted thin-plate dielectrics exhibits interfacial toughness of 645 J·m-2 or 339 J·m-2 in the transverse or longitudinal direction, respectively. Additionally, the sensors demonstrate a broad measurement range from 0.85 Pa to 5000 kPa. This extended range is facilitated by the significant stiffness variation of the separated tilted thin-plate dielectrics, ranging from 0.56 kPa to 19.76 MPa. Two applications of these fully printed soft sensors, including an intelligent sensorized insole and a robotic hand combining both soft actuators and soft sensors are showcased. It is believed that the strategy, employing 3D printing for soft microstructured sensors, is a general approach not only applicable for improving the performance of soft sensors, but also conducive to designing powerful soft functional devices.

Keywords: 3D printing; fully 3D‐printed sensors and actuators; simultaneous sensing and actuation; soft robots; wearable devices.