The Intrinsic Viscosity, Translational and Rotatory Diffusion Constants of Rod-Like Macromolecules in Solution

Abstract

A theory of the intrinsic viscosities, translational and rotatory diffusion constants of rod-like macromolecules in solution is developed on the basis of a rigid-chain model made up of monomeric elements separated by rigid bonds. The general methods of previous papers are used to take proper account of the hydrodynamic interactions of the monomeric units of the molecule. The theory developed leads to results showing qualitatively, marked similarity to that obtained for cylindrical and ellipsoidal particles. The intrinsic viscosities, translatory and rotatory diffusion constants are shown, as in the case of flexible macromolecules, to be related through a pair of parameters. A method for obtaining the molecular weight of rod-like macromolecules is proposed, based on the combination of intrinsic viscosity and rotatory diffusion constant measurements.