Berlin 2005 – scientific programme
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O: Oberflächenphysik
O 53: Organische Dünnschichten V
O 53.6: Talk
Wednesday, March 9, 2005, 12:00–12:15, TU EB420
The self-assembly of alkyl-trichlorosilanes on model surfaces of biphenylthiols — •Svetlana Stoycheva1, Jörg Fick1, Steffen Franzka2, Nils Hartmann2, Alexander Kornviakov3, Avi Ulman3, Michael Himmelhaus*1, and Michael Grunze1 — 1Angewandte Physikalische Chemie, Universität Heidelberg — 2Institut für Physikalische und Theoretische Chemie, Universität Essen — 3Dept. of Chemical Engineering, Polytechnic University, Brooklyn, New York
Despite of its technological relevance, the self-assembly of monolayers of alkyl-trichlorosilanes onto oxidized metal or semiconductor surfaces is still not fully understood. Phenomena, such as island formation and polymerization, hamper the formation of densely packed and well-oriented self- assembled monolayers (SAM) in many cases. In particular, it has been found that the amount of surface-adsorbed water plays a crucial role for the process of film formation. In our study we have used rigid 4-mercaptobiphenyls (MBP) to prepare stable, molecularly engineered SAM surfaces, and used them as substrates for the study of the assembly mechanism of alkyltrichlorosilanes. SAM of 4-Methyl-4’-MBP, 4-Hydroxy-4’-MBP and MBP (as a reference system) as well as the bilayer assemblies were characterized by contact angle measurements, spectral ellipsometry, infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, sum frequency generation, and atomic force microscopy. In combination with a frequency analysis based on ab initio calculations, insight into the structure of the MBP as well as a detailed picture of the film formation of the silane overlayer could be achieved.