Effects of Fluctuating Hydrodynamic Interaction on the Hydrodynamic-Radius Expansion Factor of Polymer Chains

Abstract

The effect of fluctuating (nonpreaveraged) hydrodynamic interaction (HI) on the hydrodynamicradius expansion factor α H for the Gaussian chain with excluded volume is theoretically examined in the uniform-expansion approximation within the framework of the theory previously developed for the unperturbed Gaussian chain with fluctuating HI. It is shown that α H may be given by the product of the Zimm hydrodynamic-radius expansion factor α H (Z) and a newly introduced factor, which represents the present effect of fluctuating HI on α H and is generally smaller than unity. Thus it is concluded that the fluctuating HI decreases α H from α H (Z) . An approximate interpolation formula for α H is also constructed as a function of the conventional excluded-volume parameter z and is completed by replacing z by the scaled excluded-volume parameter z in the quasi-two-parameter scheme