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PO: Polymerphysik
PO 6: Poster: Dünne Filme und Grenzfl
ächen
PO 6.17: Poster
Dienstag, 2. März 1999, 14:00–16:00, Foyer
The hydrophobic interaction, a coalescence of gas bubbles — •J. Hauwede1, U.-C. Boehnke1, T. Remmler1, H. Motschmann2, S. Wurlitzer1, Th. M. Fischer1, and F. Kremer1 — 1Universit"at Leipzig, Fakultät für Physik, Linnéstr. 5, 04103 Leipzig — 2MPI for colloid and interface science, Rudower Chaussée 5, Berlin Adlershof
The properties of solvophobic surfaces in polar liquids are studied by sedimentation experiments as well as by force measurements using a scanning force microscope (SFM) and a surface force apparatus (SFA). Depending on whether the polar liquid contacts the solvophobic surface under normal air pressure or in vacuum the experimental results are different. Sedimentation velocities of vacuum contacted solvophobic surfaces are similar to those of solvophilic vacuum or air contacted ones. However, for the air contacted solvophobic surfaces there is a slip boundary condition of the hydrodynamic flow causing a change of the sedimentation velocity of about 20 % and a long-range attraction varying with the polarity of the liquid molecule is observed between them. These effects can be explained by an incomplete air dewetting of the solvophobic surface when brought into contact with the polar liquid at normal air pressure.