Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 14: Organic, polymeric, biomolecular films – also with absorbates I
O 14.6: Vortrag
Montag, 23. März 2009, 16:15–16:30, SCH A316
Surface Composition and Electronic Structure of Ionic Liquids - Influence of the anion (interchanged with O 14.5) — •Till Cremer1, Claudia Kolbeck1, Kevin Robert John Lovelock1, Florian Maier1, Natalia Paape2, Peter Steffen Schulz2, Peter Wasserscheid2, and Hans-Peter Steinrück1 — 1Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, 91058 Erlangen — 2Lehrstuhl für Chemische Reaktionstechnik, Egerlandstr. 3, 91058 Erlangen
Ionic Liquids (ILs) are a new class of solvents exhibiting unique physico-chemical properties. They are promising candidates for many applications in electrochemistry, synthesis, separation and lubrication technologies, and catalysis. For many of these processes knowledge of the interface, e.g. the IL-vacuum interface is of fundamental value. Due to their extremely low vapour pressure IL surfaces can be investigated under ultra high vacuum conditions such as X-ray photoelectron spectroscopy (XPS). In an extended angle resolved XPS (ARXPS) study, the near surface region of a wide range of 1-octyl-3-methyl-imidazolium based Ionic Liquids (ILs) was investigated. While for all IL surfaces enhancement of the alkyl chain was observed by ARXPS, the level of alkyl enhancement was found to be significantly dependent on the nature of the anion. Moreover, careful analysis of the fine strucure of the C 1s region resulted in observation of an anion-dependent difference in relative binding energy positions for chemically different carbon species present in the imidazolium cation. These shifts were compared and correlated to 1H- and 13C-NMR measurements. This work was supported by the DFG through SPP 1191 "Ionic Liquids".