Influence of chain stiffness, grafting density and normal load on the tribological and structural behavior of polymer brushes: A nonequilibrium-molecular-dynamics study

Manjesh K. Singh, Patrick Ilg, Rosa M. Espinosa-Marzal, Nicholas D. Spencer, Martin Kröger

Research output: Contribution to journalArticlepeer-review

Abstract

We have performed coarse-grained molecular-dynamics simulations on both flexible and semiflexible multi-bead-spring model polymer brushes in the presence of explicit solvent particles, to explore their tribological and structural behaviors. The effect of stiffness and tethering density on equilibrium-brush height is seen to be well reproduced within a Flory-type theory. After discussing the equilibrium behavior of the model brushes, we first study the shearing behavior of flexible chains at different grafting densities covering brush and mushroom regimes. Next, we focus on the effect of chain stiffness on the tribological behavior of polymer brushes. The tribological properties are interpreted by means of the simultaneously recorded density profiles. We find that the friction coefficient decreases with increasing persistence length, both in velocity and separation-dependency studies, over the stiffness range explored in this work.

Original languageEnglish (US)
Article number254
JournalPolymers
Volume8
Issue number7
DOIs
StatePublished - Jul 8 2016

Keywords

  • Bending stiffness
  • Boundary lubrication
  • Coefficient of friction
  • FENE-chain model
  • Planar brush
  • Polymer brushes
  • Semiflexible polymers
  • Shear
  • Solvent quality

ASJC Scopus subject areas

  • Chemistry(all)
  • Polymers and Plastics

Fingerprint

Dive into the research topics of 'Influence of chain stiffness, grafting density and normal load on the tribological and structural behavior of polymer brushes: A nonequilibrium-molecular-dynamics study'. Together they form a unique fingerprint.

Cite this