High-throughput tensile testing of silver nanowires

Abstract

Silver nanowires (Ag NWs) have been used in various nanostructured materials such as stretchable electronics due to their small size, high strength, and high conductivity. Envisioned nanostructured materials employ millions of nanostructures to achieve its function, yet due to challenges in sample preparation, mechanical characterization has been limited to a small number of samples. The results thus have limited statistical significance, important, for example, for the case of fracture strain, which is a stochastic variable. Here, we show highly-dense and unidirectional alignment of penta-twinned Ag NWs on top of polyethylene terephthalate (PET) substrates using microfluidics. Surface treatment enabled strong bonding between NWs and substrates. We then conducted tensile stretching of the substrates in the direction of alignment, capturing images of the induced deformation and fracture of the NWs, effectively testing many of them in tension simultaneously. We analyzed their fracture strain using digital image correlation (DIC). We show results for more than 200 samples, achieving a statistical quantification of NW fracture strain, useful for the design of applications and nanostructured materials based on them, such as stretchable electronics.