Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)

O 55.73: Poster

Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F

Self-assembled monolayers on gold containing azobenzene ligands — •F. Vogel¹, M. Borg¹, F. Bretthauer², U. Siemeling², and F. Träger¹ — ¹Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology - CINSaT, Universität Kassel, Kassel — ²Institut für Chemie and Center for Interdisciplinary Nanostructure Science and Technology - CINSaT, Universität Kassel, Kassel

Two azobenzene-derivatized 1,2-dithiolanes were synthesized and used for the preparation of self-assembled monolayers (SAM) on gold. Azobenzene derivatives can be switched between their ”cis” and ”trans” isomers by irradiation with light and represent the most widely studied system for photoresponsive SAMs. However, in SAMs based on thiols and symmetric disulfids on gold, the chromophores are densly packed and show little free volume to allow photoisomerisation. The binding unit of the investigated molecules with their two attachment points and increasing size should lead to considerable void spaces between the individual photoresponsive azo units. Photoswitching was confirmed by ellisometric measurements. The kinetics of film formation of the two molecules have been compared by in situ optical second harmonic generation (SHG). It has been shown that the absorption of the molecules on the gold substrate is best described by second order Langmuir kinetics for the investigated concentration of 100 µmol/l.