We present the first study of mixed alkanethiolate SAMs on ultrasmooth gold surfaces. By eliminating surface roughness, it became possible, for the first time, to investigate wetting properties as a function of surface chemical composition. In three different surface compositions, it was found that contact-angle hysteresis apparently vanished. This suggests that surface chemical heterogeneity does not contribute to contact-angle hysteresis in mixed SAMs on ultrasmooth gold surfaces.

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Self-assembled monolayers (SAMs) of omega-substituted biphenylthiolates (omega-MBP) on gold were characterized by spectral ellipsometry, X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRRAS), and vibrational sum frequency generation spectroscopy (VSFG). The vibrational studies of the SAMs were supported by an ab initio frequency analysis at HF/6-31G and BP86/6-31G levels, yielding an assignment of all relevant spectral features in the range from 3500 to 1200 cm(-1). We were able to demonstrate that hydroxy-terminated MBP (HMBP) SAMs are basically featureless in the range of the CH stretching vibrations. Accordingly, the adsorption of a SAM of octadecyltrichlorosilane (OTS) on top of this model surface could be studied. A red shift of the C-O stretching vibration from 1281 to 1264 cm(-1) was observed during the chemisorption of OTS, thus allowing for a quantification of the number of OTS molecules involved in surface binding of OTS, which was found to be about 26% on average.

Selbstorganisierte Monolagen ohne messbare Kontaktwinkelhysterese auf der Basis von aliphatischen und aromatischen Organothiolen werden mit einer Variante des konventionellen „template stripping“ gefertigt. Hierbei werden Organothiollösungen als aufspaltende Reagentien eingesetzt, um Glimmer ohne mechanischen Stress von einer Goldoberfläche zu lösen. Die ultraflachen SAM‐Oberflächen (siehe rasterkraftmikroskopische Aufnahme) liefern neue Daten über Grenzflächeneigenschaften wie das Benetzungs‐ und Adhäsionsverhalten.