| Autor: |
Mayer S; Institute of Particle Technology, Department of Chemical and Biological Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany., Bergen A; Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany., Zhai Z; Institute of Advanced Optical Technologies─Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering and Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 8, 91052 Erlangen, Germany., Trzeciak S; Computer Chemistry Center/Theoretical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelsbachstr. 25, 91052 Erlangen, Germany., Chu J; Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany., Zahn D; Computer Chemistry Center/Theoretical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelsbachstr. 25, 91052 Erlangen, Germany., Koller TM; Institute of Advanced Optical Technologies─Thermophysical Properties (AOT-TP), Department of Chemical and Biological Engineering and Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Str. 8, 91052 Erlangen, Germany., Meyer K; Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr.1, 91058 Erlangen, Germany., Vogel N; Institute of Particle Technology, Department of Chemical and Biological Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany. |
| Abstrakt: |
In this study, we systematically analyze the surface tension and Hansen solubility parameters (HSPs) of imidazolium-based ionic liquids (ILs) with different anions ([NTf 2 ] - , [PF 6 ] - , [I] - , and [Br] - ). These anions are combined with the classical 1-alkyl-3-methyl-substituted imidazolium cations ([C n C 1 Im] + ) and a group of oligoether-functionalized imidazolium cations ([(mPEG n ) 2 Im] + ) based on methylated polyethylene glycol (mPEG n ). In detail, the influences of the length of the alkyl- and the mPEG n -chain, the anion size, and the water content are investigated experimentally. For [C n C 1 Im] + -based ILs, the surface tension decreases with increasing alkyl chain length in all cases, but the magnitude of this decrease depends on the size of the anion ([NTf 2 ] - < [PF 6 ] - < [Br] - ≤ [I] - ). Molecular dynamics (MD) simulations on [C n C 1 Im] + -based ILs indicate that these differences are caused by the interplay of charged and uncharged domains, in particular in the different anions, which affects the ability of the alkyl chains of the cation to orient toward the liquid-gas interface. An increase in the mPEG n -chain length of the [(mPEG n ) 2 Im][A] ILs does not significantly influence the surface tension. These changes upon variation of the cation/anion combination do not correlate with the evolution of the HSPs for the two sets of ILs. Finally, our data suggest that significant water contents up to water mole fractions of x (H 2 O) = 0.25 do not significantly affect the surface tension of the studied binary IL-water mixtures. |
