Bayreuth 1998 – wissenschaftliches Programm

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SYB: Symposium Polymere und kleine Moleküle an Grenzflächen

SYB 4: Polymere und kleine Moleküle an festen Grenzflächen

SYB 4.22: Poster

Dienstag, 10. März 1998, 18:00–20:00, P1

Formation of Alkanethiol Self-Assembled Monolayers on Oxidized Gold Surfaces — •Chun Yan¹, Armin G"olzh"auser¹, Michael Grunze¹, and Christof W"oll² — ¹Angewandte Physikalische Chemie, Universit"at Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg — ²Physikalische Chemie I, Ruhr-Universit"at Bochum, Universit"atsstr. 150, D-44801 Bochum

The formation of alkanethiol self-assembled monolayers (SAM) on oxidized gold was studied by x-ray photoelectron (XPS), near edge x-ray absorption fine structure (NEXAFS) and infrared spectroscopy. Different oxidation procedures, exposure of gold to atomic oxygen in vacuum and to UV/ozone in air, lead to different types of surface gold oxides, distinguishable by their oxygen XP spectra. On the gold oxide formed by exposure to atomic oxygen stable SAMs were formed from ethanolic solution as well as via vapor deposition. Two sulfur species were distinguished by XPS, gold thiolate and a species related to the reaction of the thiol with the oxide that was found encapsulated under the self-assembled monolayer. The monolayers adsorbed from ethanolic solution were denser packed and less tilted than the layers formed by vapor deposition and SAMs on clean gold surfaces. The gold oxide produced by exposure to UV/ozone in air was removed during thiol adsorption from ethanolic solution and a monolayer assembled on the bare gold. Chemical vapor deposition on this oxide did not lead to well defined monolayers.