A moldable PEDOT:PSS dry electrode with excellent epidermal compliance for wearable electrocardiogram monitoring

Abstract

A wearable dry electrode is necessary for the long-term recording of human biopotential signals. However, the present dry electrode does not fit the skin thoroughly at the microscale, especially during body movement and sweat secretion, leading to high interface impedance and poor signal quality. In this work, an aerogel dry electrode with excellent skin compliance was prepared by an interesting foaming process of the blends of conductive PEDOT:PSS, a surfactant, and a cross-linking agent. The resultant aerogels with micron-sized pores and high porosity show a low compressive modulus below 2 kPa and a low density of 10 mg cm⁻³. Such an ultrasoft aerogel displays impressive shape moldability, enabling self-adaptable compliance with the skin at the microscale. Owing to the good attachment and gas permeability, the dry electrodes prepared with the aerogels show lower skin-contact impedance than the standard silver/silver chloride (Ag/AgCl) gel electrode, as well as relatively insusceptible contact impedance changes to sweat secretion. The aerogel dry electrode can be employed to acquire a high-quality electrocardiogram (ECG) in different scenarios such as body movements and dry/wet skin conditions. The dry electrode shows good promise for application in long-term ECG signal monitoring in daily life.