Dynamic surface decoupling in a sheared polymer melt

Max-Planck-Institut für Polymerforschung - Ackermannweg 10, 55128 Mainz, Germany

Received: 21 December 2004
Accepted: 18 February 2005

Abstract

We propose that several mechanisms contribute to friction in a polymer melt adsorbed at a structured surface. The first one is the well-known disentanglement of bulk polymer chains from the surface layer. However, if the surface is ideal at the atomic scale, the adsorbed parts of polymer chains can move along the equipotential lines of the surface potential. This gives rise to a strong slippage of the melt. For high shear rates chains partially desorb. However, the friction force on adsorbed chains increases, resulting in quasi-stick boundary conditions. We propose that the adsorbed layers can be efficiently used to adjust the friction force between the polymer melt and the surface.