SCATTERING FUNCTION AND THE DYNAMICS OF PHASE-SEPARATION IN POLYMER MIXTURES UNDER SHEAR-FLOW

The phenomenological mean-field theory describing concentration fluctuations and spinodal decomposition of binary mixtures of long flexible macromolecules is generalized to mixtures under steady shear flow. This shear flow leads to a partial orientation and stretching of the coils, as well as to an anisotropic deformation of concentration fluctuations. We obtained the collective scattering function describing these concentration fluctuations in the mixture under shear flow. Both the steady-state situation in the one-phase region and the initial stages of spinodal decomposition for concentrations within of the spinodal curve are considered.