Analysis of the heterogeneous dynamics of imidazolium-based [Tf2N-] ionic liquids using molecular simulation

Eleni Androulaki, Niki Vergadou, Ioannis Economou

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8 Citations (Scopus)

Abstract

The complex dynamic behaviour of the imidazolium-based ionic liquids [Cnmim+][Tf2N-], n = 4, 8, 12 is examined at various temperatures and at atmospheric pressure using molecular dynamics simulation. An existing all-atom force field is further optimised in order to attain reasonable agreement with experimental data for transport properties, such as self-diffusivities and viscosities. Dynamical heterogeneity phenomena are quantified through the calculation of the non-Gaussian parameter and the deviation of the self-part of the van Hove correlation function from the expected normal distribution. From this analysis, ions that move faster or slower than expected are detected in the system. These subsets of 'fast' and 'slow' ions form individual clusters consisting of either mobile or immobile ions. Detailed analysis of the ions diffusion reveals preferential motion along the direction of the alkyl tail for the cation and along the vector that connects the two sulphur atoms for the anion. For the longest alkyl tails, the heterogeneity in the dynamics becomes more pronounced and is preserved for several nanoseconds, especially at low temperatures.

Original languageEnglish
Pages (from-to)2694-2706
Number of pages13
JournalMolecular Physics
Volume112
Issue number20
DOIs
Publication statusPublished - 18 Oct 2014

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Keywords

  • Dynamic heterogeneity
  • Ionic liquids
  • Molecular simulation

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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