Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.1: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

Interfacial behaviour of thin films of ionic liquids on mica — •Alexey Deyko, Florian Rietzler, Hans-Peter Steinrück, and Florian Maier — Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, Erlangen, 91058, Germany

We present a comprehensive study of ultrathin films of ionic liquids (ILs) deposited on mica surface. The ILs used are [C1C1Im][Tf2N] (1,3-dimethylimidazolium bis(trifuoromethyl)imide), and [C4C1Im][Tf2N] (1-butyl-3-octylimidazolium bis(trifuoromethyl)imide). These ILs can be successfully employed in a variety of electrochemical applications, for instance in solar cells. However, little information is available on the interfacial structure of ILs at charged surfaces. Due to its atomically flat surface and relatively simple preparation, mica is an ideal candidate for our studies. Ultra thin films of ILs in the sub-monolayer regime up to several nm thicknesses were prepared using a physical vapour deposition method under ultra high vacuum conditions. Employing angle resolved x-ray photoelectron spectroscopy (ARXPS), top and interface layers were probed with respect to adsorption behaviour, molecular orientation, and growth mode. It was found that the investigated ILs grow in a three-dimensional fashion and form islands on mica surface, even at coverages below one monolayer. That result is noticeably different to a case, when ILs are deposited on a metal surface, such as Au(111), where films grow in a layer-by-layer fashion wetting the Au surface. Supported by the DFG through SPP 1191 and by the Cluster of Excellence Engineering of Advanced Materials.