An elastomeric transparent composite electrode based on copper nanowires and polyurethane

An elastomeric transparent composite electrode has been fabricated comprising a percolation network of copper nanowires (CuNWs) embedded in the surface layer of an elastomeric polyurethane (PU) matrix. The composite electrode was fabricated by first forming a highly conductive CuNW network on glass, then overcoating with a layer of a liquid polyurethane precursor which was subsequently polymerized, and finally peeling off the resulting PU sheet. The composite retained the elastomeric stretchability of the polymer matrix. Pre-treatment of the CuNW network with 6-aminohexanoic acid enhanced the bonding between nanowires and PU matrix, and significantly improved the reversibility of the surface conductance of the composite electrode during repeated stretching at room temperature. The composite electrodes exhibited a low sheet resistance of <10(2) Omega sq(-1) at tensile strains up to 60%. High stretchability was obtained in a wide range of strain rates over 200 cycles of stretching. Morphological development during the stretching-releasing processes was consistent with the important role of the bonding between the nanowires and the PU matrix in the stretchability of the composite electrode.