On the Effective Diffusion Tensor of a Segment in a Chain Molecule and its Application to the Non-Newtonian Viscosity of Polymer Solutions

Abstract

The effect of hydrodynamic interaction between segments in a chain molecule plays an important role in the theory of the intrinsic viscosity of high polymer solutions. In this paper, the effect of hydrodynamic interaction is reflected into the concept of the effective diffusion tensor of a segment in a chain molecule. In performing the calculation, r i G , the distance from the centre of gravity of the chain molecule to the cited segment, is considered as a parameter. In result, each segment has an anisotropic effective diffusion tensor, the radial component of which is about 10% larger than the transversal ones on the average. With this anisotropic diffusion tensor, the shear gradient dependence of the intrinsic viscosity of polymer solutions is deduced, making use of Rouse model. The agreement with experiments is satisfactory.