Suppression of excluded-volume exponents in shear flow of dilute polymer solutions.

Abstract

The analogy between polymer and binary critical fluid dynamics in simple shear flow is used to construct a renormalization-group analysis of the scaling exponent \ensuremath{\nu} for the end-to-end distance of an isolated long polymer chain in a good solvent undergoing strong shear flow. The shear flow induces a crossover from the usual fixed point with the good solvent Flory exponent \ensuremath{\nu} to a new, strong shear fixed point with the classical exponent \ensuremath{\nu}=(1/2. Based on the blob picture we argue that the dynamic exponent z is not affected by the flow and remains at its zero shear, z=3 value. Experimentally observable consequences of this result are also discussed.