ELECTROHYDRODYNAMICS OF RIGID MACROMOLECULES WITH PERMANENT AND INDUCED DIPOLE-MOMENTS .2.

Abstract

The orientation distribution of rigid macromolecules dissolved at low concentration in a dielectric Newtonian fluid is solved for the case in which simultaneous hydrodynamic and electric fields are applied. Macromolecules are taken to be Brownian rigid spheroids of arbitrary aspect ratio and both permanent and induced dipole moments are included. To solve the problem with arbitrary strength of fields, the Galerkin method based on spherical harmonics is adopted. The converged solutions are used in the prediction of the steady state birefringence and extinction angle over very wide ranges of field strengths. Due to the coupled effects of flow and external field, somewhat complicated responses are predicted and saturation features are revealed at the strong flow limit. External field dependence due to the induced dipole is similar to that of the permanent case for most field conditions. Finally, it is shown, taking poly-gamma-benzyl-L-glutamate solutions with various molecular weights as an example, how results in this article are applicable to an analysis of a real system.