Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Charged Soft Matter, Polyelectrolytes and Ionic Liquids I
CPP 32.9: Vortrag
Mittwoch, 3. April 2019, 11:45–12:00, H13
A combined computational and experimental study on the microscopic structures in aqueous ionic liquids near solid/liquid and air/liquid interfaces — •Takeshi Kobayashi1, Andre Kemna2, Björn Braunschweig2, Maria Fyta1, and Jens Smiatek1,3 — 1Institute for Computational Physics, University of Stuttgart, Germany — 2Institute of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany — 3Helmholtz-Institute Münster: Ionics in Energy Storage (HIMS - IEK 12), Forschungszentrum Jülich, Corrensstraße 46, 48149 Münster, Germany
Even small amounts of water molecules may limit the use of common hygroscopic ionic liquids (ILs) as electrolyte solutions in electrochemical cells. Similar concentration-dependent effects can also be observed at uncharged interfaces in other solvent-IL mixtures. Here, we study the microscopic structures near uncharged interfaces using Molecular Dynamics simulations varying the water concentrations in dialkylimidazolium based ILs. A comparison between the different cation and anion species highlights a crucial relation among molecular size, shape, and the preferential binding of water to the ions. The presence of water affects the local ordering of the cation species near the interface. Vibrational sum-frequency generation (SFG) experiments are performed to study the molecular structure at the air/IL interface and can verify the results from our simulations. [1] M. Jitvisate, J. R. T. Seddon, J. Phys. Chem. C 121, 18593 (2017), [2] T. Kobayashi, et al., Phys. Chem. Chem. Phys. 19, 18924 (2017)