Sorbitol-Modified PEDOT:PSS Based Eutectic Gel Electrodes for Stable Wearable Electrophysiological Recording

Wearable bioelectrodes with high adhesion, ionic conductivity, and mechanical stability are critical for accurate and reliable electrophysiological signal acquisition. However, conventional silver/silver chloride wet electrodes and existing dry or semidry electrodes often fail to balance conductivity, adhesion, stability, and user comfort effectively. In this work, we present a eutectic gel electrode synthesized via a straightforward preparation method incorporating 2-acrylamido-2-methylpropanesulfonic acid (AMPS) to enhance mechanical strength and adhesion, alongside doping with modified PEDOT:PSS to improve electronic conductivity and reduce skin impedance. The resulting gel demonstrates high ionic conductivity (3.78 mS cm^–1), low skin impedance (∼54 kΩ·cm²), excellent toughness (90.55 kJ m^–3), and robust adhesion on diverse substrates. The electrode exhibits stable performance under cyclic mechanical deformation and environmental exposure, with negligible mass variation over 12 h. Applied as wearable sensors, the eutectic gel accurately captures strain signals from multiple joints and achieves a superior signal-to-noise ratio (22.4 dB vs 18.3 dB) compared to commercial Ag/AgCl electrodes in electrocardiogram monitoring, including during physical activity. Furthermore, surface electromyography recordings confirm the gel’s high sensitivity to muscle activity across various motions, demonstrating its promise as a multifunctional hydrogel electrode platform for long-term, noninvasive health monitoring and flexible epidermal electronics.