Hydrogel-based electrodes for high-fidelity sEMG acquisition and robotic hand control

Stable acquisition and accurate recognition of surface electromyography (sEMG) signals are key elements for building high-performance human-machine interaction (HMI) systems. Owing to their excellent flexibility, electrical conductivity, and biocompatibility, conductive hydrogels show great potential in physiological electrodes and flexible sensor applications. However, existing materials often struggle to simultaneously achieve high stretchability, good conductivity, self-healing capability, and strong interfacial adhesion. In this study, a hydrogel electrode with superior comprehensive performance was developed using acrylamide (AM) and acrylic acid (AA) as the matrix, incorporating chitosan (CS), tannic acid (TA), and glycerol (Gly) via a thermally initiated polymerization method. The resulting PCGK-CT hydrogel exhibited outstanding stretchability (elongation at break of 1250%), high conductivity (0.027 S/m), excellent sensitivity (gauge factor of 0.47 at 350% strain), high signal-to-noise ratio (SNR of 13.8 ± 0.3 dB), as well as desirable self-adhesive and self-healing properties. By integrating hydrogel electrodes with flexible electronic devices, high-fidelity sEMG signal acquisition and intelligent decoding were achieved. Combined with highly realistic motion control of a biomimetic robotic hand, this work establishes a feasible technical pathway for sEMG-based HMI systems and lays a foundation for further investigation in related extended applications.