Numerical calculation of intrinsic viscosity of star and ring polymers using a modified Zimm model

Abstract

In this study, the effect of structures of different polymers, i.e., ring and symmetrical star (with 3-6 arms), in a dilute solution (theta solvent) on their viscoelastic properties was theoretically investigated using a modified Zimm model. The shear relaxation modulus and the intrinsic viscosity of these polymer solutions can then be calculated. This theoretical approach offers a systematic way to infer the number of arms of a star polymer or the structure of the macromolecule in an unknown sample based on its corresponding viscoelastic properties, and it is applicable for polymers of any structure. Using star polymers and ring polymers as examples, it was generally found that, given the same molecular weight, the intrinsic viscosity of symmetrical star polymers decreases with increasing numbers of arms, and that a much more rapid decay is predicted in the shear relaxation modulus when the number of arms increases. In addition, the dynamics of the ring polymer in dilute solution are similar to those of the six-arm star polymer.