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


Servantie J. , MUELLER M.

PHYSICAL REVIEW LETTERS, cilt.101, sa.2, 2008 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 101 Konu: 2
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1103/physrevlett.101.026101
  • Dergi Adı: PHYSICAL REVIEW LETTERS

Özet

Using Couette and Poiseuille flows, 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 surface. delta is dictated by the ratio of bulk viscosity and surface mobility. At weakly attractive surfaces, lubrication layers form; 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 sticky surface layer is built up, giving rise to small slip lengths. Upon cooling, delta decreases at high temperatures, passes through a minimum, and grows for T -> T(g). At strongly attractive surfaces, the Navier-slip condition fails to describe Couette and Poiseuille flows simultaneously. The simulations are corroborated by a schematic, two-layer model suggesting that the observations do not depend on details of the computational model.