Comparison of Concentration Fluctuations In Homogeneous Homopolymer Blends.
19 October 1989
Concentration fluctuations have been observed dielectrically in 1,2-polybutadiene/1,4-polybutadiene homopolymer blends that are expected to be homogeneous based on their low molecular weight and interaction parameter. Most of the material has a composition close to that of the bulk, but a small fraction of the blend has a composition quite rich in 1,4-polybutadiene. The asymmetry of partitioning of polymer between the two populations is similar to that observed previously for the analogous diblock system, but the amplitudes of the concentration fluctuation are much smaller for blends than for the diblock copolymers. The difference between the two systems is symmetric and approximately the same magnitude as that predicted by Fredrickson and Helfand for concentration fluctuations in diblock copolymers.