Armadillo-inspired micro-foldable metal electrodes with a negligible resistance change under large stretchability

Abstract

Stretchable electrodes are one of the essential building blocks for stretchable electronics. However, most of the reported stretchable electrodes show a considerable conductivity decrease under large stretchability. Until now, it has still been a big challenge to develop appropriate geometric structures to realize stretchable metal electrodes with a negligible conductivity change under large stretchability. Here, inspired by the armadillo, we develop a novel micro-foldable structure on polydimethylsiloxane (PDMS) using a suspended plasma etching method. This novel structure could endow the obtained stretchable electrodes with excellent properties including high metallic conductivity (>40 000 S cm⁻¹) at released and stretched states, slight resistance change (13%) over a large tensile range (190%), a fully-covered conductive area, excellent cyclic operational stability (over 10 000 times), and a robust interface adhesion strength (>0.28 MPa). These figures of merit are very prominent compared to the reported stretchable gold electrodes, indicating the superiority of this novel micro-foldable structure. Furthermore, these stretchable electrodes show excellent performance in electromyography (EMG) signal detection, stretchable conducting wires and capacitive stretchable sensors. This work provides a novel and efficient avenue for the preparation of stretchable electronics.