Metal-polymer Interface Formation - Diffusion and Clustering of Copper in Pet

Thin Cu metal layers were deposited on semicrystalline poly(ethylene terephthalate) PET films by thermal evaporation. RBS measurements revealed that, in our metallization conditions, the Cu layers ore buried into the polymer bulk. Since the formation of a diffuse interface has important consequences on the adhesive properties, the Cu diffusion was investigated systematically by means of RBS. After metallization, the samples were annealed under vacuum for times varying between 0 and 120 hours at temperatures between 80 degrees C and 120 degrees C, slightly above the glass transition of the PET. Since the diffusion profiles exhibit a behavior in accordance with the Fick's laws, the diffusion coefficients were evaluated The results are in agreement with a diffusion model based on the Brownian motion of particles in a viscous fluid