Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Micro- and Nanofluidics II

CPP 46.6: Vortrag

Freitag, 18. März 2011, 12:00–12:15, ZEU 222

Quantitative Analysis of Fluorescence Cross Correlation Spectroscopy Data for the Study of Hydrodynamics near Surfaces — Roman Schmitz¹, Stoyan Yordanov¹, Hans-Juergen Butt¹, Kaloian Koynov¹, and •Burkhard Duenweg^1,2 — ¹Max Planck Institute for Polymer Research, Mainz, Germany — ²Dept. of Chemical Engineering, Monash University, Melbourne, Australia

We present a new method of data analysis for the interpretation of fluorescence cross correlation spectroscopy measurements in total internal reflection, from particles immersed in hydrodynamic flows near surfaces. Brownian Dynamics simulations are used to produce auto- and cross-correlation curves with defined input values of parameters like shear rate, slip length, particle diffusion constant, etc. These curves are directly compared with the corresponding experimental results. The optimum set of parameters, together with the corresponding set of their statistical errors, is the solution of a nonlinear fit problem, which is solved by an importance-sampling Monte Carlo procedure in parameter space. Substantial statistical effort in both the experiments and the numerics produces good agreement between experiment and theory, but also reveals subtle deficiencies in the underlying simulation model. Nevertheless, even the present simple model is already able to produce a fairly reliable bound on the slip length.