Temperature-dependent surface-enrichment effects of imidazolium-based ionic liquids

Kolbeck C, Deyko A, Matsuda T, Kohler F, Wasserscheid P, Maier F, Steinrück HP (2013)


Publication Type: Journal article

Publication year: 2013

Journal

Original Authors: Kolbeck C., Deyko A., Matsuda T., Kohler F.T.U., Wasserscheid P., Maier F., Steinrück H.-P.

Publisher: Wiley-Blackwell / Wiley-VCH Verlag

Book Volume: 14

Pages Range: 3726-3730

Journal Issue: 16

DOI: 10.1002/cphc.201300719

Abstract

We present the first systematic study of the influence of temperature on the degree of surface enrichment of 1-alkyl-3-methylimidazolium-based ionic liquids (ILs). Using angle-resolved X-ray photoelectron spectroscopy, we demonstrate that the degree of surface enrichment strongly decreases with increasing temperature for all the studied ILs. For ILs with the same cation, but different anions, [CCIm]Br, [CC Im][TfO] and [CCIm][TfN], no significant differences of the temperature-induced partial loss of surface enrichment are found. Measurements for [CCIm][TfO], [CCIm][TfO] and [CCIm][TfO] indicate a small effect of the chain length. For [CC Im][TfO], a continuous decrease of alkyl surface enrichment is found with increasing temperature, with no abrupt changes at the phase-transition temperature from the smectic A to the isotropic phase, indicating that the surface enrichment is not affected by this phase transition. Loss of order! The surface enrichment of the alkyl chains of five imidazolium-based ionic liquids (ILs) at the liquid/vacuum interface is studied as a function of temperature by angle-resolved X-ray photoelectron spectroscopy; both the anion and the alkyl chain length at the cation are varied. At room temperature, the alkyl chains are enriched at the outer surface. Upon increasing the temperature, the degree of surface enrichment decreases. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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APA:

Kolbeck, C., Deyko, A., Matsuda, T., Kohler, F., Wasserscheid, P., Maier, F., & Steinrück, H.-P. (2013). Temperature-dependent surface-enrichment effects of imidazolium-based ionic liquids. ChemPhysChem, 14(16), 3726-3730. https://dx.doi.org/10.1002/cphc.201300719

MLA:

Kolbeck, Claudia, et al. "Temperature-dependent surface-enrichment effects of imidazolium-based ionic liquids." ChemPhysChem 14.16 (2013): 3726-3730.

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