Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Poster: Interfaces and Thin Films (joint session with DECHEMA and VDI)

CPP 9.12: Poster

Monday, March 11, 2013, 17:30–19:30, Poster C

Controlling probe dynamics by modification of adsorption site density in confined liquids — Daniela Täuber, •Fabian Meier, and Christian von Borczyskowski — nanoMA, TU-Chemnitz, Institut für Physik

The mobility of probe molecules in confined liquids is influenced by short adsorption events at the interface. Here we report about the modification of the surface silanol density at silica substrates and its effect on single dye dynamics in ultrathin liquid films. In contrast to ensemble methods, single molecule microscopy provides information on a local scale with sub-micron resolution. Thereby, probability distributions of diffusivities (scaled square displacements at fixed time lags) yield additional details to the conventional analysis of particle tracking via calculation of mean square displacements along detected trajectories. The probe diffusion in ultrathin liquid films can be modeled by a two layer system, consisting of a heterogeneous near surface layer with slowed diffusion on silanol patches and a homogeneous upper layer[1]. Single molecule tracking experiments on substrates with modified surface silanol density are compared to simulations. High adsorption site density combined with two-dimensional confinement in mesopores allows us to use adsorbed dye molecules as probes for the dynamics of the liquid in such pores.

[1] D. Täuber, Dissertation, TU Chemnitz, 2011.