Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Interfaces and Thin Films I
CPP 17.1: Topical Talk
Dienstag, 23. März 2010, 09:30–10:00, H39
Surviving Structure in Colloidal Suspensions Confined from 3D to 2D — Yan Zeng1, Stefan Grandner2, Sabine Klapp2, and •Regine von Klitzing1 — 1Stranski-Laboratorium, Institut für Chemie, TU Berlin — 2Institut für Theoretische Physik, TU Berlin
Due to miniaturization the question arises how geometrical confinement in thin films affects the structure and dynamics of colloidal suspensions. The film thickness is between 5 - 150 nm and therefore on the same mesoscopic length scale as the distance between colloidal particles. For studying the interaction with the thin film, either a Colloidal Probe AFM or a Thin Film Pressure Balance (TFPB) was used. The resulting structural (oscillatory) forces are characterized by their period, decay length and amplitude. We have proven experimentally the predictions of the Density Functional Theory (DFT) that the confinement does not affect the characteristic lengths of the colloidal dispersion. Our results show that the wavelength obtained by the structure peak from neutron or x-ray scattering experiments at the volume phase is equal to the period of the force oscillation in the film [1,2]. In other word, the average polymer or particle distance, i.e. the concentration remains the same. The effect of different parameters like ionic strength [3] and influence of the properties of the confining surfaces (charge, softness) are shown. [3]. [1] D. Qu, J.S. Pedersen, S. Garnier, A. Laschewsky, H. Möhwald, R. v. Klitzing Macromolecules (2006) 39 7364. [2] S. Klapp, Y. Zeng, D. Qu, R. v. Klitzing Phys. Rev. Letters (2008) 100 118303. [3] S. Grandner, Y. Zeng, R. v. Klitzing, S.H.L. Klapp, J. Chem. Phys. (2009) on Web.