Self-powered flexible electronic skin tactile sensor with 3D force detection

Flexible and biocompatible self-driven sensors capable of multimodal perception are pivotal for the rapid development of wearable electronic devices. Currently, few studies have integrated the sensing of both frictional force and vertical pressure into a single, self-driven flexible sensor. Herein, we developed an acrylate (AA)-polyglutamic acid (PGA) hydrogel material that exhibits mechanical properties similar to those of skin. By integrating a triboelectric nanogenerator (TENG) into the AA-PGA hydrogel matrix, we constructed a dual-mode flexible sensor capable of utilizing biomechanical energy for multidirectional force sensing. This sensor features high sensitivity, high linearity, fast response, and excellent stability. A prototype was proposed for a robotic hand e-skin monitoring and analysis system to demonstrate the performance of the AA-PGA hydrogel sensor. As a self-driven sensor, the AA-PGA hydrogel sensor can perform real-time monitoring of physiological signals, such as wrist pulse detection and voice recognition. Moreover, it was continuously showcased in a series of personalized monitoring scenarios, including handwriting, step counting, and respiratory monitoring, further substantiating its outstanding sensing capabilities. Given these advantages, the developed AA-PGA hydrogel sensor holds great promise for applications in wearable sensors, physiological monitoring, and human–machine interfaces.