Depolarization of light scattered from dilute macromolecular solutions. I. Theoretical discussion

This paper represents an attempt to review the general interpretation of the phenomenon of depolarization of light scattered from colloidal solutions and to combine this with other recently acquired knowledge in order to predict the qualitative behavior of the depolarization ratios, as well as the individual components which make up these ratios, with respect to concentration, solute–solvent interaction, and the characteristics of the macromolecules. The ratio ρv depends inversely on the turbidity of the solution, the behavior of which is now understood due to the investigations of the light scattering method relative to molecular weight determinations. If allowance is made for turbidity changes and the effects of intramolecular interference ρv reflects the optical anisotropy of the segments of polymer molecules and of rigid molecules as a whole. The values of ρh will generally diminish from a value of unity as the size of the scattering particle increases. Sniall rodlike particles appear to be an exception to this behavior according to the works of Gans and Neugebauer but experimental confirmation is lacking notwithstanding recent claims to the contrary.