Investigation of Copper and Tantalum atoms Diffusion in Polymers by ab initio Molecular Dynamics

摘要

Ab initio MD simulations were carried out to characterize the diffusion of Cu and Ta atoms/clusters inside a SiLK-like amorphous polymer. The diffusion coefficients of Cu and Ta atoms and their atomic clusters in linear amorphous and crosslinked polymers were calculated. The speed of a single Cu atom within the polymer suggests that Cu atoms diffuse in amorphous polymers by jumping or hopping between cavities inside polymers. The diffusion speed of Ta is much lower than that of Cu. This is not only due to its larger mass but also due to the chemical interactions between Ta and polymers. It was found that the degree of polymer crosslinking doesn't have strong effects on metal diffusion. Studies on the diffusion of metal clusters showed smaller diffusion coefficients with larger cluster size. This is the first effort to calculate the diffusion coefficients of metal atoms/clusters inside polymers using ab initio MD simulations; it provides a framework for metal-polymer diffusion investigations.