Dynamic heterogeneity and phase separation kinetics in miscible poly(vinyl acetate)/poly(ethylene oxide) blends by local dielectric spectroscopy

Local dielectric spectroscopy (LDS) was employed to analyze the miscible blend composed of poly(vinyl acetate) (PVAc) and poly(ethylene oxide) (PEO). The two homopolymers have very different relaxation times and glass transition temperatures. The aim was to study the dynamic heterogeneity in films as a function of the film thickness. Measurements of the local blend composition at the nanoscale have shown that LDS is sensitive to the dynamic heterogeneity. In thinner films, phase segregation occurs, and the kinetics of phase demixing was studied using as a probe the change in local composition. These results open new possibilities for studying interdiffusion and adhesion at polymer-polymer interfaces as a function of annealing temperature with LDS.