Berlin 2008 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Confined Fluids
CPP 12.6: Talk
Tuesday, February 26, 2008, 12:15–12:30, C 230
Structuring of colloidal suspensions confined in thin liquid films — •Yan Zeng1, Sabine Klapp1,2, and Regine v.Klitzing1 — 1Stranski-Laboratorium für Physikalische & Theoretische Chemie, Institut für Chemie, TU Berlin — 2Institut für Theoretische Physik, TU Berlin
In order to study the structuring of colloidal suspensions Ludox silica solutions are confined between a microsphere and a flat interface in a colloidal probe AFM [1]. Oscillatory forces are measured due to layer by layer expulsion of the particles [2]. The period scales with the concentration with an exponent -1/3, this period has the same value as the particle distance in the corresponding bulk solution calculated from the position of the structure peak of SAXS measurements. The addition of salt decreases the period of oscillation, the amplitude and the scaling exponent of the particle distance in dependence of the salt concentration. In addition, simulations show that the scaling behavior changes from exponent -1/3 at low ionic strength to a concentration independent length at high ionic strength [3].
[1] M.Piech, J.Y.Walz, J.Colloid Interface Sci. 2002,8,2985
[2] J.Israelachvili, Intermolecular and surface Forces; Academic Press: San Diego, CA, 1992; Chapter 13
[3] S.Klapp, D.Qu, R.v.Klitzing, J.Phys.Chem.B 2007,111,1296.