Uni-Logo Koordinatoren des Kolloquiums:
Prof. Dr. F. Schmidt-Kaler
Institut für Physik
Johannes Gutenberg-Universität
Prof. Dr. Hartmut Wittig
Institut fuer Kernphysik,
Johannes Gutenberg-Universitaet

Physikalisches Kolloquium Mainz

Institut für Kernphysik, Johann Joachim Becher Weg 45

Dienstag, den 27.11.2018 um 16 Uhr c.t. im HS KPH
Tee ab 15:45 Uhr

Ordering of hydrophilic and hydrophobized silica particles

Prof. Dr. Regine von Klitzing, Technische Universität Darmstadt

The presentation addresses ordering phenomena of Silica suspensions under confinement in a Colloidal Probe AFM (CP-AFM). The wavelength λ scales with the particle number density as λ=ρ-1/3. An extrapolation towards high volume fractions shows that the ρ-1/3 scaling law for λ ends up into a cubic lattice found for one-component systems like organic solvents, where λ=d (d: diameter of molecules, particles etc.). A deviation from the exponentially decaying cosine function was found and can be described by an additional repulsion term [2,3] which will be discussed. Furthermore, it will be shown how oscillatory forces can be switched on and off by external stimuli [4]. Partially hydrophobized Silica particles order laterally at the interfaces of a free-standing film. They can form percolation networks which seem to stabilize foam films and even foams, i.e. so called Pickering foams

Kontakt: Andrea Graham, andrea.graham@uni-mainz.de