Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Interfaces and Thin Films I

CPP 17.11: Vortrag

Dienstag, 23. März 2010, 12:30–12:45, H39

Analysis of heterogeneous diffusion in ultra-thin liquid films via single particle tracking — •Ines Trenkmann, Daniela Täuber, Michael Bauer, and Christian von Borczyskowski — Chemnitz University of Technology, Institute of Physics, Germany

It has been well known for some years that the dynamical behavior of tracers in ultra-thin liquid films differs from the behavior in a bulk liquid. In previous studies of single dye diffusion in TEHOS-films (deposited on Si wafers with a thermally grown oxide layer) we could show that single particle tracking can reveal heterogeneous behavior of the used tracers [1]. Thereby the diffusion is influenced by dynamic and static heterogeneities [2]. The first ones are caused by changes between layers with distinct diffusion coefficients and the influence of the hydrodynamic boundary conditions. The latter are caused by surface heterogeneities, such as the inhomogeneous distribution of silanol groups on the silicon oxide surface. In recent studies we could show that the determined diffusion coefficients depend strongly on the applied evaluation method [3]. The determinations of the mean squared displacement just yield averaged diffusion coefficients. We are using short range diffusion coefficients from the analysis of scaled squared displacements at different time lags to obtain further information about the contributing heterogeneous components.

[1] Schuster, J., et al.: Eur. Polym. J. 40 (2004) 993

[2] Bauer, M., et al.: Diffusion Fundamentals 11 (2009) 70

[3] Trenkmann, I., et al.: Diffusion Fundamentals submitted

[4] Täuber, D.; et al.: Diffusion Fundamentals 11 (2009) 76