X-ray and Neutron Reflectometry for the Investigation of Polymer Diffusion

Abstract

X-ray and neutron reflectometry are novel tools for the investigation of polymer interfaces. For this method we demonstrate the high resolution on the vertical length scale which is normally better than 1 nm and the ideal applicability for the analysis of polymer diffusion by showing both simulations and measurements. The limits and difficulties are discussed. We look at the broadening of the interface between two polystyrene films during interdiffusion slightly above the glass transition temperature. For short times we prove two distinct time regimes for polymer diffusion. This is achieved with a double layer system consisting of a deuterated and a protonated polystyrene film. The roughness of the individual films is well below 1 nm.