Silver and epoxy binder-based printed electrodes and the effect of silver nanoparticles on stretchability

In recent years, there has been a lot of research on printed paste and ink composite electrode material made with metallic-based materials such as silver nanowires, silver nanoparticles, and flakes with epoxy-based binders. These stretchable electrode materials must exhibit metal-level conductivity and high interfacial adhesion that can withstand necking and deformation stress. To overcome several issues including the low adhesion properties found in silicone-based binders and the low heat resistance found in urethane-based binders, we synthesized a binder material with over 300% stretchability and high adhesive strength. This was done by modifying an epoxy to produce a binder that can be easily applied to various materials without special surface treatment technologies. In addition, we developed a printable, stretchable electrode material with high adhesive strength, high conductivity, and high stretchability by mixing three types of silver powders (flake, spherical micro-particle, and nanoparticle) with the modified epoxy binder. Results from electrode conductivity, stretchability, repetitive fatigue property, and residual strain analyses demonstrate that these properties are highly dependent on nanoparticle content and distribution. The electrode resistivities ranged from 8.5 × 10⁻⁵ to 2.5 × 10⁻⁵ Ω cm after heat curing at 170 °C and showed excellent stability at strain of over 140%.