Highly Stretchable Conductive Electrode Composed of Silver Flake and Ecoflex

Abstract

Stretchable electronic devices commonly require interconnectors with high stretchability, conductivity, and durability. In this work, we demonstrated a highly stretchable electrode based on a composite of silver (Ag) flake filler and Ecoflex binder. The stretchable composite material was printed on polyurethane substrate. To improve the dispersibility and printability of the composite material, poly(dimethylsiloxane-ethylene oxide polymeric) was used. The effects of Ag flake content and Ecoflex binder materials on the electromechanical properties of the stretchable electrode were investigated via stretching and cyclic stretching tests. As the amount of Ag flake increased, the electrical conductivity of the electrode increased as well, but the stretchability decreased. Use of Ecoflex 00-10 material, with its softer and lower Young's modulus, greatly improved the stretchability of the electrode—allowing it to stretch to a strain of up to 120%. The stretchable electrode withstood repetitive cyclic stretching durability tests of 10,000 cycles. The addition of carbon black also had a great impact on its electromechanical properties. An electrode fabricated with 0.2 wt% carbon black showed the highest conductivity and excellent stretchability of more than 150%.