Dynamics of a Suspension of Spheres and Rigid Polymers: Effect of Geometrical Mismatch

TL;DR

This paper investigates how the geometrical mismatch between spheres and polymers affects their suspension dynamics, including diffusion and viscosity, using an effective medium and multiple scattering approach.

Contribution

It introduces a theoretical framework to analyze the steady-state dynamics of sphere-polymer suspensions considering geometrical mismatch effects.

Findings

Diffusion coefficients and viscosity are derived for various volume fractions.

Dynamics freeze when polymer volume fraction approaches 0.31.

An optimal sphere volume fraction maximizes differences in polymer diffusion based on geometry.

Abstract

An effective medium approach together with a multiple scattering formalism is considered to study the steady-state dynamics of suspensions of spheres and rigid stiff polymer chains (Gaussian) without excluded volume interactions. The translational diffusion coefficients of the moving probe sphere and of the probe polymer chain, and the shear viscosity of the suspensions have been derived for finite volume fractions of spheres FSP and of polymers FPOL. The role of the geometrical parameter t=R_g/a ("a" is the radius of any sphere and R_g the radius of gyration of a polymer chain) is discussed. Dynamics of the probe objects is frozen when FPOL approaches 0.31. An optimum range of FSP that maximizes the difference in the diffusion coefficients of polymer chains characterized by distinct "t" values has been noticed.