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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.72: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
A x-ray reflectivity study of the structural arrangement of ionic liquids at solid interfaces — •Markus Mezger1, Harald Reichert1, Moshe Deutsch2, Benjamin Ocko3, Heiko Schröder1, John Okasinski1, Sebastian Schöder1,4, Lilach Tamam2, Helmut Dosch1, and Veijo Honkimäki4 — 1Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart — 2Bar-Ilan University, Dept. of Physics, Ramat-Gan 52900, Israel — 3Brookhaven National Laboratory, Upton, NY 11973, USA — 4European Synchrotron Radiation Facility, F-38043 Grenoble, France
Room temperature ionic liquids (IL) are promising candidates for a variety of new technological processes, ranging from applications as special solvents in green chemistry to catalytic reactions in biotechnology. Although crucial for the understanding of solvent properties, only little is known about the structural rearrangement of anions and cations at solid interfaces. To get access to these deeply buried interfaces, high energy x-ray reflectivity (∼ 70 keV) is an ideal tool. In our systematic study, we observed differently ordered structures, caused by changes in composition, water content, and temperature. By choosing different combinations of anion and cation, we can tune the ion-ion and ion-substrate interaction. Trace amounts of water dissolved in the ILs can interact with the solid surface or the ions, and therefore alter the interfacial properties significantly. By varying the temperature, we can change the ratio between entropy, and interfacial energy, favoring a disordered liquid, or interfacial layering respectively.