Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation

D.A. Turton, J. Hunger, A. Stoppa, G. Hefter, A. Thoman, M. Walther, R. Buchner, K. Wynne, U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder), Deutsche Forschungsgemeinschaft (Funder)

Research output: Contribution to journalArticle

212 Citations (Scopus)

Abstract

We have measured the intermolecular dynamics of the 1,3-dialkylimidazolium-based room-temperature ionic liquids (RTILs) [emim][BF4], [emim][DCA], and [bmim][DCA] at 25 degrees C from below 1 GHz to 10 THz by ultrafast optical Kerr effect (OKE) spectroscopy and dielectric relaxation spectroscopy (DRS) augmented by time-domain terahertz and far-infrared FTIR spectroscopy. This concerted approach allows a more detailed analysis to be made of the relatively featureless terahertz region, where the higher frequency diffusional modes are strongly overlapped with librations and intermolecular vibrations. Of greatest interest though, is an intense low frequency (sub-alpha) relaxation that we show is in accordance with recent simulations that have reported mesoscopic structure arising from aggregates or clusters-structure that explains the anomalous and inconveniently high viscosities of these liquids.
LanguageEnglish
Pages11140-11146
Number of pages6
JournalJournal of the American Chemical Society
Volume131
Issue number31
DOIs
Publication statusPublished - 12 Aug 2009

Fingerprint

Optical Kerr effect
Ionic Liquids
Dielectric relaxation
Ionic liquids
Spectrum Analysis
Agglomeration
Spectroscopy
Dielectric Spectroscopy
Viscosity of liquids
Fourier Transform Infrared Spectroscopy
Vibration
Viscosity
Infrared spectroscopy
Temperature

Keywords

  • effect ohd-oke
  • intermolecular dynamics
  • temperature-dependence
  • nanostructural organization
  • physical-properties
  • molecular-dynamics
  • glass-transition
  • spectroscopy
  • solvation
  • chloride

Cite this

Turton, D. A., Hunger, J., Stoppa, A., Hefter, G., Thoman, A., Walther, M., ... Deutsche Forschungsgemeinschaft (Funder) (2009). Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation. Journal of the American Chemical Society, 131(31), 11140-11146. https://doi.org/10.1021/ja903315v
Turton, D.A. ; Hunger, J. ; Stoppa, A. ; Hefter, G. ; Thoman, A. ; Walther, M. ; Buchner, R. ; Wynne, K. ; U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder) ; Deutsche Forschungsgemeinschaft (Funder). / Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation. In: Journal of the American Chemical Society. 2009 ; Vol. 131, No. 31. pp. 11140-11146.
@article{89417407737f42f79c133b0c77f87e8a,
title = "Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation",
abstract = "We have measured the intermolecular dynamics of the 1,3-dialkylimidazolium-based room-temperature ionic liquids (RTILs) [emim][BF4], [emim][DCA], and [bmim][DCA] at 25 degrees C from below 1 GHz to 10 THz by ultrafast optical Kerr effect (OKE) spectroscopy and dielectric relaxation spectroscopy (DRS) augmented by time-domain terahertz and far-infrared FTIR spectroscopy. This concerted approach allows a more detailed analysis to be made of the relatively featureless terahertz region, where the higher frequency diffusional modes are strongly overlapped with librations and intermolecular vibrations. Of greatest interest though, is an intense low frequency (sub-alpha) relaxation that we show is in accordance with recent simulations that have reported mesoscopic structure arising from aggregates or clusters-structure that explains the anomalous and inconveniently high viscosities of these liquids.",
keywords = "effect ohd-oke, intermolecular dynamics, temperature-dependence, nanostructural organization, physical-properties, molecular-dynamics, glass-transition, spectroscopy, solvation, chloride",
author = "D.A. Turton and J. Hunger and A. Stoppa and G. Hefter and A. Thoman and M. Walther and R. Buchner and K. Wynne and {U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder)} and {Deutsche Forschungsgemeinschaft (Funder)}",
year = "2009",
month = "8",
day = "12",
doi = "10.1021/ja903315v",
language = "English",
volume = "131",
pages = "11140--11146",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "31",

}

Turton, DA, Hunger, J, Stoppa, A, Hefter, G, Thoman, A, Walther, M, Buchner, R, Wynne, K, U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder) & Deutsche Forschungsgemeinschaft (Funder) 2009, 'Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation' Journal of the American Chemical Society, vol. 131, no. 31, pp. 11140-11146. https://doi.org/10.1021/ja903315v

Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation. / Turton, D.A.; Hunger, J.; Stoppa, A.; Hefter, G.; Thoman, A.; Walther, M.; Buchner, R.; Wynne, K.; U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder); Deutsche Forschungsgemeinschaft (Funder).

In: Journal of the American Chemical Society, Vol. 131, No. 31, 12.08.2009, p. 11140-11146.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical kerr effect study: evidence for mesoscopic aggregation

AU - Turton, D.A.

AU - Hunger, J.

AU - Stoppa, A.

AU - Hefter, G.

AU - Thoman, A.

AU - Walther, M.

AU - Buchner, R.

AU - Wynne, K.

AU - U.K. Engineering and Physical Sciences Research Council (EPSRC) (Funder)

AU - Deutsche Forschungsgemeinschaft (Funder)

PY - 2009/8/12

Y1 - 2009/8/12

N2 - We have measured the intermolecular dynamics of the 1,3-dialkylimidazolium-based room-temperature ionic liquids (RTILs) [emim][BF4], [emim][DCA], and [bmim][DCA] at 25 degrees C from below 1 GHz to 10 THz by ultrafast optical Kerr effect (OKE) spectroscopy and dielectric relaxation spectroscopy (DRS) augmented by time-domain terahertz and far-infrared FTIR spectroscopy. This concerted approach allows a more detailed analysis to be made of the relatively featureless terahertz region, where the higher frequency diffusional modes are strongly overlapped with librations and intermolecular vibrations. Of greatest interest though, is an intense low frequency (sub-alpha) relaxation that we show is in accordance with recent simulations that have reported mesoscopic structure arising from aggregates or clusters-structure that explains the anomalous and inconveniently high viscosities of these liquids.

AB - We have measured the intermolecular dynamics of the 1,3-dialkylimidazolium-based room-temperature ionic liquids (RTILs) [emim][BF4], [emim][DCA], and [bmim][DCA] at 25 degrees C from below 1 GHz to 10 THz by ultrafast optical Kerr effect (OKE) spectroscopy and dielectric relaxation spectroscopy (DRS) augmented by time-domain terahertz and far-infrared FTIR spectroscopy. This concerted approach allows a more detailed analysis to be made of the relatively featureless terahertz region, where the higher frequency diffusional modes are strongly overlapped with librations and intermolecular vibrations. Of greatest interest though, is an intense low frequency (sub-alpha) relaxation that we show is in accordance with recent simulations that have reported mesoscopic structure arising from aggregates or clusters-structure that explains the anomalous and inconveniently high viscosities of these liquids.

KW - effect ohd-oke

KW - intermolecular dynamics

KW - temperature-dependence

KW - nanostructural organization

KW - physical-properties

KW - molecular-dynamics

KW - glass-transition

KW - spectroscopy

KW - solvation

KW - chloride

UR - http://dx.doi.org/10.1021/ja903315v

U2 - 10.1021/ja903315v

DO - 10.1021/ja903315v

M3 - Article

VL - 131

SP - 11140

EP - 11146

JO - Journal of the American Chemical Society

T2 - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 31

ER -