Perturbation Theory of the Intrinsic Viscosity of Polymer Chains

Abstract

Our previous calculation of the intrinsic viscosity [η] of linear flexible polymer chains is improved by the inclusion of interactions between excitations, which interactions arise mainly from fluctuations in the hydrodynamic interaction tensor. In the equation [η]=φ×10²³L³/M (where L in the root‐mean‐square end‐to‐end distance and M in the molecular weight; cgs units), φ was found to equal 2.68 in the previous zeroth order approximation. In first‐order perturbation theory φ decreases to 1.81, and in second order φ rises in excess of 2.66. An approximate summation to infinite order of the interaction responsible for the large decrease in first order, and other considerations are adduced in support of the view that the remaining terms of the perturbation series are relatively small.