Surface Tension and Viscosity of Binary Mixtures of the Fluorinated and Non-fluorinated Ionic Liquids [PFBMIm][PF6] and [C4C1Im][PF6] by the Pendant Drop Method and Surface Light Scattering

Koller TM, Lenahan F, Schmidt P, Klein T, Mehler J, Maier F, Rausch MH, Wasserscheid P, Steinrück HP, Fröba AP (2020)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2020

Journal

International Journal of Thermophysics Springer Verlag (Germany)

Book Volume: 41

Article Number: 144

Journal Issue: 10

DOI: 10.1007/s10765-020-02720-w

Abstract

Mixtures of fluorinated and non-fluorinated ionic liquids (ILs) show a distinct structural organization in the bulk and at the surface. To understand how such microscopic effects influence the macroscopic bulk and surface properties of IL mixtures, knowledge of corresponding thermophysical properties including viscosity and surface tension is required yet lacking. With the intention of investigating surface enrichment effects of the fluorinated IL [PFBMIm][PF6] (3-methyl-1-(3,3,4,4,4-pentafluorobutyl)imidazolium hexafluorophosphate) in mixtures with the structurally similar, non-fluorinated IL [C4C1Im][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) observed with angle-resolved X-ray photoelectron spectroscopy (ARXPS), the pendant drop method and surface light scattering (SLS) were applied in the present study to determine surface tension and dynamic viscosity between (293 and 368) K. By adding small amounts of [PFBMIm][PF6] up to 9 mol %, a distinct increase in the viscosity and decrease in the surface tension of the mixtures relative to the properties of pure [C4C1Im][PF6] was found. This behavior reflects the nanosegregated structure in the bulk and at the surface of the binary IL mixtures. Using the results about the pronounced surface enrichment of the fluorinated chain of [PFBMIm][PF6] quantified by ARXPS, a linear mixing rule for the surface tension of the IL mixtures based on the surface tensions of the pure ILs and the surface concentration of their most surface-active groups is suggested.

Authors with CRIS profile

Thomas Manfred Koller Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Frances Lenahan Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Patrick Schmidt Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Tobias Klein Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Julian Mehler Lehrstuhl für Chemische Reaktionstechnik Florian Maier Lehrstuhl für Physikalische Chemie II Michael Rausch Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Peter Wasserscheid Lehrstuhl für Chemische Reaktionstechnik Hans-Peter Steinrück Lehrstuhl für Physikalische Chemie II Andreas Paul Fröba Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP)

Additional Organisation(s)

Erlangen Graduate School in Advanced Optical Technologies

Related research project(s)

Preparation of project "Properties of the gas-liquid interface of surface-enhanced SILP systems" within Collaborative Research Center "Catalysis at Liquid Interfaces" July 1, 2019 - June 30, 2020

How to cite

APA:

Koller, T.M., Lenahan, F., Schmidt, P., Klein, T., Mehler, J., Maier, F.,... Fröba, A.P. (2020). Surface Tension and Viscosity of Binary Mixtures of the Fluorinated and Non-fluorinated Ionic Liquids [PFBMIm][PF6] and [C4C1Im][PF6] by the Pendant Drop Method and Surface Light Scattering. International Journal of Thermophysics, 41(10). https://dx.doi.org/10.1007/s10765-020-02720-w

MLA:

Koller, Thomas Manfred, et al. "Surface Tension and Viscosity of Binary Mixtures of the Fluorinated and Non-fluorinated Ionic Liquids [PFBMIm][PF6] and [C4C1Im][PF6] by the Pendant Drop Method and Surface Light Scattering." International Journal of Thermophysics 41.10 (2020).

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