Conformable, Thin, and Dry Electrode for Electrocardiography Using Composite of Silver Nanowires and Polyvinyl Butyral

Development of a thin and dry electrode for electrocardiography (ECG) is essential in order to prevent skin irritation, allergic reactions from electrolytic gel, and motion artifacts caused by relative motion between the electrodes and the skin. In this study, we have developed a composite electrode made from Ag nanowires (AgNWs) and polyvinyl butyral (PVB), prepared by inverted layer processing (ILP). The initial composite electrodes were mechanically stable, flexible, and transparent; however, most of the NWs were located beneath the surface of the PVB such that few conductive pathways were exposed and available to contact the skin. In order to resolve this issue, prior to transferring the AgNWs from the temporary glass substrate to the PVB, we irradiated the NWs with intensive pulsed light. This irradiation induced plasmonic heating of the AgNWs, which caused the NWs to sink towards the glass and form a dense layer on the temporary substrate. Subsequent ILP resulted in the fabrication of an AgNWs/PVB composite electrode that demonstrated significant surface coverage of conductive pathways available for stable electrical contact with skin. The resultant composite electrode is an improved ECG electrode that exhibits fewer motion artifacts compared to conventional Ag/AgCl-based wet electrodes since it is both dry and conformable. Graphical Abstract