Density scaling of structure and dynamics of an ionic liquid
Journal article, 2020

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.

Author

Henriette Wase Hansen

Chalmers, Physics, Materials Physics

Roskilde University (RUC)

Institut Laue-Langevin

Filippa Lundin

Chalmers, Physics, Materials Physics

Karolina Adrjanowicz

University of Silesia in Katowice

Bernhard Frick

Institut Laue-Langevin

Aleksandar Matic

Chalmers, Physics, Materials Physics

Kristine Niss

Roskilde University (RUC)

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 22 25 14169-14176

SwedNESS

Swedish Foundation for Strategic Research (SSF) (GSn15-0008), 2017-01-01 -- 2020-12-31.

Swedish Foundation for Strategic Research (SSF) (GSn15-0008), 2016-07-01 -- 2021-06-30.

Subject Categories

Physical Chemistry

Atom and Molecular Physics and Optics

DOI

10.1039/d0cp01258k

PubMed

32609117

More information

Latest update

9/9/2020 9