Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 13: Solid / liquid interfaces I

O 13.5: Vortrag

Montag, 14. März 2011, 16:00–16:15, WIL B321

What fluorinated water-solid interfaces tell us about the origin of the hydrophobic gap. — •Markus Mezger¹, Felix Sedlmeier², Dominik Horinek², and Harald Reichert³ — ¹Max-Planck-Institut für Polymerforschung, Mainz — ²Physik Department, TU München — ³European Synchrotron Radiation Facility, Grenoble, France

The density deficit of water at hydrophobic interfaces, frequently called the hydrophobic gap, has been the subject of numerous experimental and theoretical studies. Recent experiments give values for the interfacial depletion that consistently correspond to less than a monolayer of water. However, its origin and the relation to the chemistry and molecular geometry of a particular hydrophobic coating or with macroscopic parameters such as the contact angle are still unclear. To elucidate how the underlying mechanisms affect the extent of the interfacial depletion we carried out a high-energy X-ray reflectivity study of water adjacent to a perfluorinated hydrophobic surface with a spatial resolution on the molecular scale. Comparison of experimental data and MD simulations on perflurinated and hydrocarbon water-solid interfaces revealed the influence of different contributions to the observed interfacial depletion.

Reference: M. Mezger et al., J. Am. Chem. Soc. 132, 6735-6741 (2010).