Robust, self‐adhesive, and low‐contact impedance polyvinyl alcohol/polyacrylamide dual‐network hydrogel semidry electrode for biopotential signal acquisition

Abstract

Abstract Herein, we fabricated a flexible semidry electrode with excellent mechanical performance, satisfactory self‐adhesiveness, and low‐contact impedance using physical/chemical crosslinked polyvinyl alcohol/polyacrylamide dual‐network hydrogels (PVA/PAM DNHs) as an efficient saline reservoir. The resultant PVA/PAM DNHs showed admirable adhesive and compliance to the hairy scalp, facilitating the establishment of a robust electrode/skin interface for biopotential signal transmission. Moreover, the PVA/PAM DNHs steadily released trace saline onto the scalp to achieve the minimized potential drift (1.47 ± 0.39 mV/min) and low electrode–scalp impedance (18.2 ± 8.9 kΩ @ 10 Hz). More importantly, the application feasibility of real‐world brain−computer interfaces (BCIs) was preliminarily validated by 10 participants using two classic BCI paradigms. The mean temporal cross‐correlation coefficients between the semidry and wet electrodes in the eyes open/closed and the N200 speller paradigms are 0.919 ± 0.054 and 0.912 ± 0.050, respectively. Both electrodes demonstrate anticipated neuroelectrophysiological responses with similar patterns. This semidry electrode could also effectively capture robust P‐QRS‐T peaks during electrocardiogram recording. Considering their outstanding advantages of fast setup, user‐friendliness, and robust signals, the proposed PVA/PAM DNH‐based electrode is a promising alternative to wet electrodes in biopotential signal acquisition.

Keywords

• brain–computer interface
• dual‐network hydrogel
• electrocardiogram signals
• electroencephalography signals
• semidry electrode