Flexible Dry Epidermal Electrophysiological Electrodes Based on One-Dimensional Platinum-Coated Silver Nanowires

Abstract

Electrodes or sensors based on silver nanowires (AgNWs) are gaining increasing value in diverse fields such as health monitoring, smart devices, body movement monitoring, and biomedical applications. However, pure AgNWs tend to degrade over time when exposed to an ambient atmosphere, severely limiting the mechanical and electrical performances of AgNW-based electrodes. Here, we take AgNWs and poly(dimethylsiloxane) (PDMS) as the basic research materials and employ a simple displacement reaction and spin-coating process to prepare one-dimensional platinum-coated AgNWs/PDMS (Pt-AgNWs/PDMS) flexible electrodes. The as-prepared electrodes display comparable electrical conductivity (∼1.65 S/cm), stability (40 min of continuous ultrasound), and flexibility (2500 repetitions of cyclic stretching) compared to pure AgNWs/PDMS electrodes. The resistance even remains consistent at the initial state after 12000 s in a H2SO4 etching medium, indicating that the anticorrosive property of Pt can further enhance the durability and stability of the electrodes. Moreover, the low contact impedance (33.1 kΩ at 1 kHz) of Pt-AgNWs/PDMS electrodes facilitates the capture of various physiological signals, including electrooculogram (EOG), electrocardiogram (ECG), and electromyogram (EMG), which is suitable for applications requiring stable long-term recording. Thus, the proposed strategy shows potential, and Pt-AgNWs are expected to be an ideal material for the fabrication of next-generation high-performance epidermal electrophysiological electrodes.