Effect of molecular structure on liquid slip

Ajay Vadakkepatt, Yalin Dong, Seth Lichter, Ashlie Martini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Slip behavior of three liquids with distinct molecular shapes-linear (hexadecane), branched (pentaerythritol tetra), and a chain of rings (polyphenylether)-is studied using molecular dynamics simulation and reduced-order modeling. Slip at a liquid-solid interface is shown to be affected by the molecular structure of the liquid. A two-dimensional Frenkel-Kontorova model captures the fundamental structural features of the liquid molecules and gives insight into how molecules flex and slip along the surface. We formulate an approximation to the Peierls-Nabarro energy which incorporates both the position of liquid atoms relative to substrate atoms and molecular flexibility. We find that increased molecular flexibility can lead to reduced slip by allowing the liquid to conform epitaxially to the substrate with only a small energetic penalty. Liquid molecules which are less flexible can conform to the substrate only with greater expense of conformational energy, and so exhibit larger slip.

Original languageEnglish (US)
Article number066311
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume84
Issue number6
DOIs
StatePublished - Dec 14 2011

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

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