Weak Molecular Interactions in Organic Composite Dry Film Lead to Degradable, Robust Wireless Electrophysiological Signal Sensing

Abstract

Long-term and highly sensitive electrophysiological signal detection is the primary issue for wearable health monitoring. The critical issues of pre-gelled wet electrodes as conventional approaches are limited conductivity and low adhesivity owing to the dependence of moisture concentration. Along this line, this paper presents a biocompatible, mechanically robust, water degradable, and intrinsically conductive organic composite dry film electrode based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), hydroxyethyl cellulose, and dopamine. The effects on PEDOT:PSS structure transition are studied systematically according to the combination of each component with various analytical methods including morphological, chemical, electrical, and mechanical characterization. The proposed film exhibits high conductivity (292 S m(-1)) and robust mechano-electrical stability (only 8% of resistance change under 110 of fully flat-bended cycles) owing to the weak but synergetic interactions between the components. Furthermore, low noise, clear signal, and long-term stability for a wireless electrocardiogram and electromyogram signal sensing is achieved using the proposed dry electrode.