High-throughput craze studies in gradient thin films using ductile copper grids

Polymer materials are being developed and used for numerous photonic and electronic applications where the polymer is expected to maintain its dielectric properties in confined geometries. In these applications, the initiation or growth of mechanically induced defects, such as crazes, cracks, or shear bands, can significantly alter the intended function of the polymer. In this paper, we introduce a high throughput methodology to facilitate the investigation of craze growth in confined films. Specifically, we extend the previous research conducted on the effects of film thickness on crazing of polystyrene into unexplored thickness regimes of films less than 100 nm. We combine novel techniques of gradient thin film preparation, the established methodology of the copper grid strain test, the automated features of atomic force microscopy, and batch image processing to provide increased throughput and standardization in our quantitative measurements. We demonstrate that the mechanisms of craze widening and micronecking are quantitatively continuous to film thicknesses as thin as 50 nm.