Estimation of the elastic modulus of Au nanofilms by subtracting the polymeric substrate influence

Abstract

The elastic modulus of Au nanofilms deposited onto a polymeric substrate was estimated by subtracting the substrate mechanical influence from the Au/polymer system under axial tensile test. To select the most appropriate substrate between polyethylene- terephthalate (PET) and Kapton (polyimide), the crystallinity and structural isotropic conditions were previously examined by X-ray diffraction. Kapton shows a lower % of crystallinity and enhanced isotropic conditions than PET. The elastic modulus of 60 nm-thick Au films deposited onto Kapton was measured, resulting in an average value of 37 GPa, which is lower than the Au bulk value. Crystalline structure and elastic properties of polymeric substrates are found to be of great relevance to be considered for the determination of the mechanical properties of metallic films.