Screening regimes for the viscosity of concentrated polymer solutions

Abstract

Our previous theory of the concentration dependence of the viscosity of polymer solutions is generalized to treat gaussian chains in the intermediate draining case. It is shown that the high concentration polymer viscosity displays two distinct screening regimes with an intermediate transition zone. The low concentration regime is characterized by a screening constant and a specific polymer viscosity which is proportional to the polymer concentration c. The high concentration regime sets in for concentrations approaching bulk values and has a Debye-like screening constant ∝c^½ and a concentration independent specific polymer viscosity. Throughout the screening regime, the polymer viscosity has a Rouse-like molecular weight dependence, despite the full inclusion of hydrodynamic interactions.