Stretchable and Self-Adhesive\nPEDOT:PSS Blend with\nHigh Sweat Tolerance as Conformal Biopotential Dry Electrodes

Abstract

Dry epidermal electrodes that can always form conformal\ncontact\nwith skin can be used for continuous long-term biopotential monitoring,\nwhich can provide vital information for disease diagnosis and rehabilitation.\nBut, this application has been limited by the poor contact of dry\nelectrodes on wet skin. Herein, we report a biocompatible fully organic\ndry electrode that can form conformal contact with both dry and wet\nskin even during physical movement. The dry electrodes are prepared\nby drop casting an aqueous solution consisting of poly­(3,4-ethylenedioxythiophene):polystyrenesulfonate\n(PEDOT:PSS), poly­(vinyl alcohol) (PVA), tannic acid (TA), and ethylene\nglycol (EG). The electrodes can exhibit a conductivity of 122 S cm^–1 and a mechanical stretchability of 54%. Moreover,\nthey are self-adhesive to not only dry skin but also wet skin. As\na result, they can exhibit a lower contact impedance to skin than\ncommercial Ag/AgCl gel electrodes on both dry and sweat skins. They\ncan be used as dry epidermal electrodes to accurately detect biopotential\nsignals including electrocardiogram (ECG) and electromyogram (EMG)\non both dry and wet skins for the users at rest or during physical\nmovement. This is the first time to demonstrate dry epidermal electrodes\nself-adhesive to wet skin for accurate biopotential detection.