Enhanced Conductivity in Highly Stretchable Silver and Polymer Nanocomposite Conductors

In stretchable conductors, there is a trade-off relationship between the stretchability and conductivity which makes it difficult to increase both properties simultaneously. From a practical point of view, however, high conductivity is a more important parameter for real-world applications of wearable and mobile electronics. To obtain a highly conductive stretchable conductor, we developed a stretchable conductor composed of silver (Ag) flat-type microparticles, Ag nanoparticles and a polyester binder. The printed stretchable conductor was then sintered using the intense pulse light sintering technique. The effects of different mixing ratios of Ag flat-type particles and nanoparticles on dispersibility, printability, surface properties, conductivity, and stretchability were examined. Increasing the content of Ag-flat type particles in the composite improved dispersibility, printability, and conductivity. The stretchable conductor exhibited the outstanding conductivity of 5.5×10⁶ S/m. Increasing the Ag nanoparticles content increased the stretchability of the conductor. As the nanoparticle content increased to 30%, the stretchable conductor showed the excellent stretchability of 210%, and withstood 2,600 repeated stretching cycles at a fixed tensile strain of 50%. The conductors also exhibited superb foldability during 10,000 repeated folding tests, up to a radius of 1 mm, without any failures.