Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 45: Focus Session: Catalysis at Liquid Interfaces

O 45.7: Vortrag

Mittwoch, 7. September 2022, 17:15–17:30, H4

Surfaces of ionic liquids studied by ARXPS and UHV Pendant Drop — •Ulrike Paap, Florian Maier, and Hans-Peter Steinrück — Chair of Physical Chemistry II, FAU Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany

Ionic liquids (ILs) are characterized by a low melting point, low vapor pressure and low surface tension. Many ILs exhibit high gas solubility along a high chemical and thermal stability. Such properties are beneficial in many areas such as gas absorbents, refrigerants, lubricants, antistatics and surfactants. In this work, we studied various imidazolium-based ILs with different functional PEG chains attached to the cation using angle-resolved X-ray photoelectron spectroscopy (ARXPS) and a new pendant drop setup, which enables to measure the surface tension also in ultrahigh vacuum (UHV). With ARXPS, we determine the surface composition of the topmost IL nanometers on the molecular level. We combine these results with our surface tensions studies in UHV and atmosphere. Our results allow for a deeper understanding of enrichment and molecular orientation processes at the outermost surface of these systems in a microscopic and macroscopic range.

This work was supported by the European Research Council (ERC) through an Advanced Investigator Grant (ILID 693398) to HPS and the Collaborative Research Center (CRC) 1452: Catalysis at Liquid Interfaces.