Stretchable Conductive Organic Blends With Robust Dry/Wet Adhesion for All‐Weather Epidermal Biopotential Monitoring of Human and Turtles

Self-adhesive dry epidermal electrodes can be used to accurately monitor epidermal biopotentials even during physical movement. For continuous health monitoring, they should adhere to skin in both dry and underwater conditions. But the dry electrodes reported in literature cannot keep good adhesion under water. Here, we report fully organic blends that exhibit good adhesion to skin in both dry and underwater conditions, high conductivity, and mechanical stretchability and their application as conformal electrodes to accurately detect epidermal biopotentials under all conditions. The blends are consisted of poly(ethylenedioxythiophene):poly(styenesulfonate) (PEDOT:PSS, a conducting polymer), polyvinyl butyral (PVB), and tannic acid (TA). Different from other adhesives, their adhesion to skin can be greatly enhanced by water soaking. Because of the adhesion to skin under dry and underwater conditions, they can form conformal contact to skin during physical movement even under water. Hence, they can be used as conformal electrodes to accurately monitor epidermal biopotential signals, such as electrocardiogram (ECG) and electromyogram (EMG), under all conditions including underwater. In addition to human, we also demonstrate their application as conformal electrodes to continuously monitor the ECG signals of an amphibious turtle for 15 days.