The viscosity-radius relationship for concentrated polymer solutions

Abstract

A key assumption of polymer physics is that the random chain polymers extend in flow. Recent experimental evidence has shown that polymer chains compress in Couette flow in a manner counter to expectation. Here, scaling arguments and experimental evidence from the literature are used to determine the relationship between the viscosity, η, and chain radius of gyration, RG. The viscosity-radius of gyration relationship is found to be η∼Rm(γ˙)G where m(γ˙) is the power law exponent of the viscosity-temperature relationship that depends on the specific polymer-solvent system and the shear rate, γ˙. The viscosity is shown to be a power law function of the radius, and to decrease with decreasing r..