A Fully Flexible Hydrogel Electrode for Daily EEG Monitoring

Electroencephalography (EEG) equipment and data analysis algorithms have made great progress in the field of brain-computer interfaces (BCIs). However, the development of EEG electrodes that directly contact with users is relatively slow, especially in daily EEG monitoring. The installation procedure of wet electrodes widely used in hospitals and clinics is complicated, largely limiting its application in the family. Herein, we report a fully flexible hydrogel electrode for daily EEG monitoring. The materials used in the electrode are all flexible, making it suitable for the curvature of the skin, convenient to install, and comfortable to wear. The addition of glycerol to the hydrogel enhanced its moisturizing performance, and the hydrogel still maintained a strong elasticity after being placed in the air for 90 days. The EEG signals of alpha oscillation during eyes closed were successfully collected, and the average coherence between hydrogel electrodes and Ag/AgCl wet electrodes reached 0.910. The prepared hydrogel electrode shows satisfactory performance, providing an effective strategy for daily EEG monitoring.