Stretching nanowires on a stretchable substrate: A method towards facile fracture testing and elastic strain engineering

Abstract

Nanomaterials are building blocks for a wide range of applications. They typically exhibit ultrahigh strength, which make them also promising candidates for elastic strain engineering. Here we demonstrate a potentially facile method to measure fracture strain and strain distribution of nanomaterials, with Ag nanowires as an example. Nanowires are placed on top of or embedded in a stretchable substrate (i.e., elastomer), either as-prepared (van der Waals interactions) or treated with UV ozone (chemical bonding), which is subjected to uniaxial tensile loading. Nonlinear and bilinear cohesive shear-lag models can well capture the interfacial shear stress transfer characteristics associated with the two types of interactions, respectively. For each type, interfacial parameters such as stiffness, shear strength, and/or fracture toughness are identified by fitting the measured average strains of the nanowires. The nanowires embedded in as-prepared and on top of treated substrate are found to fracture under large substrate strain. The fracture strain and strain distribution along the nanowires are predicted using the shear-lag models. This method can be readily applied to investigate fracture and elastic strain engineering of 1D nanomaterials (regardless of aligned or inclined with respect to the stretching direction) and 2D nanomaterials.