title: Thermo-Osmotic Flow in Thin Films.
abstract: We report on the first microscale observation of the velocity field imposed by a nonuniform heat content along the solid-liquid boundary. We determine both radial and vertical velocity components of this thermo-osmotic flow field by tracking single tracer nanoparticles. The measured flow profiles are compared to an approximate analytical theory and to numerical calculations. From the measured slip velocity we deduce the thermo-osmotic coefficient for both bare glass and Pluronic F-127 covered surfaces. The value for Pluronic F-127 agrees well with Soret data for polyethylene glycol, whereas that for glass differs from literature values and indicates the complex boundary layer thermodynamics of glass-water interfaces.
authors.affiliation: Molecular Nanophotonics Group, Institute of Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany.
authors.forename: Andreas P
authors.initials: AP
authors.lastname: Bregulla
authors.affiliation: Laboratoire Ondes et Matière d'Aquitaine, Université de Bordeaux & CNRS, 33405 Talence, France.
authors.forename: Alois
authors.initials: A
authors.lastname: Würger
authors.affiliation: BioNanotechnology and Structure Formation Group, Department of Chemistry and Food Chemistry, Chair of Physical Chemistry, Measurement and Sensor Technology, Technische Universität Dresden, 01062 Dresden, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Günther
authors.affiliation: BioNanotechnology and Structure Formation Group, Department of Chemistry and Food Chemistry, Chair of Physical Chemistry, Measurement and Sensor Technology, Technische Universität Dresden, 01062 Dresden, Germany.|Kurt-Schwabe-Institut für Mess- und Sensortechnik e.V. Meinsberg, 04736 Waldheim, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Mertig
authors.affiliation: Molecular Nanophotonics Group, Institute of Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Cichos