Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 88: Molecular Films
O 88.3: Talk
Friday, March 15, 2013, 11:00–11:15, H38
self-assembled monolayers of partially fluorinated alkanethiols on gold and GaAs substrates — •Hao Lu1, Andreas Terfort2, and Michael Zharnikov1 — 1Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany — 2Institute for Inorganic und Analytical Chemistry, Frankfurt University, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany
Self-assembled monolayers (SAMs) of partially fluorinated alkanethiols (PFAT) gained substantial attention during past years because of their rigidity, oleophobicity, thermal stability, and potential use as nanoscale corrosion inhibitors. To better understand and use these properties it is important to obtain information on the structure and organization of the PFAT monolayers. In this context, we studied SAMs of a series of the PFAT molecules with the variable length of the fluorocarbon chain, viz. CF3(CF2)n(CH2)11SH (FnH11SH, n = 6, 8, and 10), on Au(111) and GaAs(001) by high resolution X-ray photoelectron spectroscopy, near edge X-ray absorption fine structure spectroscopy, and infrared reflection absorption spectroscopy. We demonstrate that FnH11SH form highly ordered and densely packed self-assembled monolayers on both these substrates, which is mediated by the thiolate-substrate bond. The orientational order is high on both Au and GaAs but deteriorates to some extent with the decreasing length of the fluorocarbon chain. This deterioration is more pronounced for GaAs which is intrinsically prone to degradation and oxidation and is, therefore, a quite sensitive substrate for molecular self-assembly.