A LIGHT-SCATTERING THEORY FOR FILLED DILUTED POLYMER-SOLUTION UNDER FLOW

Light scattering by dilute flexible polymer solutions filled with sphe rical particles is studied theoretically within the framework of the R ayleigh-Gans-Debye approximation. The basic idea of our work is that t he perturbation of stream lines and flow rates due to the presence of the particles will change the local conformation of the chains, thus i nducing a light scattering contribution. This is treated by considerin g viscosity fluctuations. The Rayleigh ratio is derived as a function of the viscosity fluctuation correlation function for the four major p olarization configurations (HH, VV, HV and VH) in shear and elongation al flow. Considering a random distribution of the particles, the small angle light scattering patterns are calculated.