Temperature dependence of the slip length in polymer melts at attractive surfaces

Abstract

Using Couette and Poiseuille flow, we extract the temperature dependence of the slip length, $\delta$, from molecular dynamics simulations of a coarse-grained polymer model in contact with an attractive, corrugated surface. $\delta$ is dictated by the ratio of bulk viscosity and surface mobility. At weakly attractive surfaces, a lubrication layer forms, $\delta$ is large and increases upon cooling. Close to the glass transition temperature, $T_g$, very large slip lengths are observed. At a more attractive surface, a``stick y surface layer" is build up, which gives rise to a small slip length. Upon cool ing, $\delta$ decreases at high temperatures, passes through a minimum and grows upon approaching $T_g$. At strongly attractive surfaces, the Navier-slip condit ion fails to describe Couette and Poiseuille flow simultaneously. The simulation results are corroborated by a schematic, two-layer model suggesting that the ob servations do not depend on the details of the computational model.

submitted to Phys. Rev. Lett

References in corpus (4)

• Cyclic motion and inversion of surface flow direction in a dense polymer brush under shear
• Tuning density profiles and mobility of inhomogeneous fluids
• Slip-controlled thin film dynamics
• Statics and dynamics of a cylindrical droplet under an external body force

Cited by in corpus (2)

• Shear rate threshold for the boundary slip in dense polymer films
• Slip effects in polymer thin films