Shear thinning near the rough boundary in a viscoelastic flow

Abstract

When polymer melts flow near a corrugated boundary, individual chains go through oscillatory shear due to the perturbed velocity field produced by corrugation. In order to obtain friction constant for this surface, we find total dissipation using the oscillatory strain rate of individual chains. For small slip velocities this friction constant approaches the constant obtained by macroscopic hydrodynamics (P. G. De Gennes, C. R. Acad. Sci. Paris Ser. B, 289:220, 1979). Large slip velocities mean smaller time period of shear oscillation, so less dissipation and we observe shear thinning. PACS: 47.57.Ng; 47.85.md; 61.25.H