A highly stretchable, helical copper nanowire conductor exhibiting a stretchability of 700%

Recent advances in unconventional foldable and stretchable electronics have forged a new field in electronics. However, traditional conducting metal oxides and metal thin films are inappropriate as electrodes for stretchable devices because they are vulnerable to tensile strain as well as bending strain. In this study, we describe the fabrication of annealing-free, copper nanowire (CuNW)-based stretchable electrodes using an inexpensive metal source through a simple and scalable process at low temperature without a vacuum. We also introduce a reversible and extremely stretchable (up to 700% of strain) helical, CuNW-based conducting spring, which has not been previously used for stretchable electrodes. Jooho Moon, Sunho Jeong and colleagues in South Korea have fabricated conducting meshes and extremely stretchable helices from copper nanowires. Metallic nanowires that are randomly entangled with each other in flexible meshes are of interest as electrical conductors for stretchable electronics. The researchers from Yonsei University and the Korea Research Institute of Chemical Technology fabricated nanowires made of copper with a simple and scalable process based on room-temperature chemical synthesis. When the nanowires were deposited on a flexible polymer substrate, the resulting meshes could stretch to up to twice their original size. When shaped as a helix, the nanowires showed an even greater stretchability of up to 700%. Being more cost-efficient than the silver nanowires used previously for similar applications, these copper nanowires hold a great promise for stretchable electronic circuits or in wearable electronics. A highly stretchable CuNW electrode was fabricated on PDMS substrate by the vacuum filtration method. The fundamental stretchability of CuNW films was demonstrated with a newly structured PDMS matrix. Our novel helix-structured CuNW/PDMS electrode showed excellent stretchability at an extremely high strain of 700%, showing a resistance variation of 3.9.