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The structure of the water–propane interface investigated by x‐ray reflectivity measurements
Author(s) -
Paulus Michael,
Gutt Christian,
Tolan Metin
Publication year - 2008
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2851
Subject(s) - propane , adsorption , surface tension , thin film , chemistry , x ray reflectivity , capillary wave , analytical chemistry (journal) , reflectivity , layer (electronics) , surface roughness , materials science , thermodynamics , optics , composite material , chromatography , organic chemistry , nanotechnology , physics
We present an x‐ray reflectivity study of the water–propane interface. The vertical structure of the interface is analyzed and the adsorption of thin layers of propane on the water surface is observed. An increase of layer thickness with rising pressure is found. The electron density of the thin films is identical with the corresponding value of bulk liquid propane. From the adsorption isotherm we determine the Hamaker constant of the system, which shows a considerably higher value compared to calculations based on the Lifshitz theory. The surface tension of the molecularly thin layer is reduced in comparison to the bulk value. The measured surface roughness is in good agreement with a modified model based on capillary wave fluctuations of the water‐propane–gas interfaces. Copyright © 2008 John Wiley & Sons, Ltd.