Buckling behavior of highly oriented silver nanowires encapsulated within layer-by-layer films

Unidirectionally oriented silver nanowires encapsulated into a nanoscale polymeric film result in anisotropic mechanical response of the composite film with much stiffer (fivefold) properties in the direction of nanowire orientation. This difference is caused by the fact that under a longitudinal compressive stress (parallel to the direction of orientation), the individual nanowires undergo the buckling process, thus, contributing into the higher composite stiffness of the film. This matrix-induced buckling phenomenon can be used as a fast and straightforward method of measuring the elastic modulus of the metallic nanowires from the buckling spacing with good precision. Using Euler's equation for the buckling instability of a slender column, the Young's modulus of silver nanowires was determined to be 118 +/- 14 GPa, which is higher than that of the bulk silver but falls within the range of values obtained with other independent measurements.