Fast Mutual Diffusion in Polymer Blends

Abstract

Mutual-diffusion and tracer-diffusion coefficients, $D$ and ${D}^{*}$, are measured in the miscible polymer blend system polystyrene + poly (2,6-dimethyl-1,4-phenyleneoxide) by forward recoil spectrometry. We find $D$ to be much larger than ${D}^{*}$, an increase that is predicted quantitatively by a theory which includes the entire chemical-potential driving force for interdiffusion.