Density scaling of structure and dynamics of an ionic liquid

Henriette Wase Hansen*, Filippa Lundin, Karolina Adrjanowicz, Berhard Frick, Aleksandar Matic, Kristine Niss

*Corresponding author

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Room temperature ionic liquids are salts with low melting points achieved by employing bulky and asymmetrical ions. The molecular design leads to apolar and polar parts as well as the presence of competing Coulomb and van der Waals interactions giving rise to nano-scale structure, e.g. charge ordering. In this paper we address the question of how these nano-scale structures influence transport properties and dynamics on different timescales. We apply pressure and temperature as control parameters and investigate the structure factor, charge transport, microscopic alpha relaxation and phonon dynamics in the phase diagram of an ionic liquid. Including viscosity and self diffusion data from literature we find that all the dynamic and transport variables studied follow the same density scaling, i.e. they all depend on the scaling variable Γ = ργ/T, with γ = 2.8. The molecular nearest neighbor structure is found to follow a density scaling identical to that of the dynamics, while this is not the case for the charge ordering, indicating that the charge ordering has little influence on the investigated dynamics.
Original languageEnglish
JournalRoyal Society of Chemistry. Database Newsletter
Volume2020
Issue number25
Pages (from-to)14169-14176
Number of pages8
DOIs
Publication statusPublished - 17 Jun 2020

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