Patterning Adhesive Layers for Array Electrodes via Electrochemically Grafted Polymers

Electrophysiological sensors (electrodes) are used to collect complex electrophysiological signals, providing extensive information about the body's condition. Reliable signal acquisition necessitates stable skin-electrode interfaces to prevent adverse effects arising from interface variations. Although the incorporation of conductive adhesive layers can improve the stability of these interfaces, in array electrodes, the layer may also cause short circuits and signal crosstalk. Here, we propose a general strategy for patterning the adhesive layer of array electrodes based on electrochemically grafted adhesive polymers (EGAPs). Utilizing the conductivity differences between the sensing sites and the substrate material of flexible electrodes, spatial selective loading of adhesive and ionically conductive polymers can be achieved through in situ electrochemical reactions, thus realizing spontaneous patterning. This EGAP-based method allows for a rapid and selective electrode surface modification in just two steps. Furthermore, array electrodes with EGAP acquired stable electrophysiological signals while improving the stability of the skin-electrode interface and the quality of signal collected and effectively avoided signal crosstalk between arrayed sensing sites.