Fabrication and characterization of stretchable copper electrodes on poly(dimethylsiloxane) substrate by direct deposition

Stretchable Cu electrodes are fabricated by direct deposition on He-and O-2-plasma-treated and prestretched poly( dimethylsiloxane) ( PDMS) substrates. The electrodes show conductivity owing to the formation of a hard and thin silica-like blocking layer, which forms low-period wavy structures on the PDMS substrate surface. The stretchable Cu electrode fabricated with He-plasma treatment shows superior performance compared with that fabricated with O-2-plasma treatment under a strain condition owing to the lack of -OH groups on the surface. In situ microscopy images obtained under strain conditions indicate that the good stretching capability of the stretchable Cu electrode originates from its low-frequency ( long-period) wavy structure. X-ray photoelectron spectroscopy measurements are performed to study the various impurities in the stretchable Cu electrode. (C) 2017 The Japan Society of Applied Physics