Structure Evolution during Spinodal Decomposition of Polymer Blends

Abstract

The evolution with time of the structure factor of a polymer mixture after a step from the one-phase region into a spinodal range is analyzed on the basis of the theory developed by Binder. The solution of the equation of motion which includes the effect of the random thermal forces provides a picture which differs in the short-time behavior from the predictions of the Cahn-Hilliard model. For all wave vectors q an increase in the intensity is expected: the point of intersection common to all curves which is characteristic for the Cahn-Hilliard model does not show up. It appears generally difficult to extract relaxation times for q values above the growth rate maximum from a time-dependent scattering experiment.