Microscopic Origin of the Non-Newtonian Viscosity of Semiflexible Polymer Solutions in the Semidilute Regime

Abstract

One of the great goals in polymer physics is to relate the various macroscopic features of polymeric fluids with the microscopic behavior of single chains. Here, we directly visualize the conformational dynamics of individual semiflexible polymers in a semidilute solution above the overlap concentration under shear. We observe that the tumbling dynamics are significantly slowed down, in marked contrast to the case of a dilute solution, due to steric interactions with neighboring filaments. The observed macroscopic shear thinning effect can be rationalized by a simple model based on the single filament dynamics.