Hydrogel-Based Electrodes for High-Fidelity sEMG Signal Acquisition Applied to Robotic Hand Control in Limb Function Reconstruction

Surface electromyography (sEMG) acquisition and recognition play a critical role in limb function reconstruction and assistive rehabilitation. 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, 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 the hydrogel electrodes with flexible electronic devices, high-fidelity sEMG signal acquisition and intelligent decoding were achieved. Coupled with a biomimetic robotic hand capable of highly realistic motion control, this system provides an efficient and natural solution for limb function restoration and assistive rehabilitation.