Dresden 2014 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 54: Poster Session 3

CPP 54.3: Poster

Thursday, April 3, 2014, 15:00–19:00, P2

Fluorescence correlation spectroscopy at reflecting substrates for investigation of vertical sample modulations — •Daniela Täuber, Kathrin Radscheit, Michael Schulz, and Christian von Borczyskowski — Institut für Physik, TU Chemnitz, Germany

Fluorescence correlation spectroscopy (FCS) is widely used for characterization of dynamic material properties [1]. The usually employed confocal laser profiles render a vertical resolution of 1 micron. Reflecting substrates create interference patterns which allow for a vertical modulation of the fluorescence signal [2] in the range of 100-200 nm. Employment of spacer layers [2] and proper choice of excitation wavelength and fluorescent dyes or material properties, therefore, allows for tailored investigation of the vertical modulation of physical properties accessible by FCS. Here we present a modified correlation function for translational diffusion in thin films on reflecting substrates. Boundary effects and long range interactions affect the dynamics of materials and tracer molecules [3], in particular, within highly structured materials such as liquid crystals films [4] and liquid crystalline biomaterials. We apply the presented correlation function to investigate the dynamics of perylenediimides in thin liquid crystal films on silicon wafers with and without a 100 nm thick silica spacer layer.

[1] E.P. Petrov, P. Schwille, Springer Series on Fluorescence. Springer, 2008, 145-197. [2] A. Lambacher, P. Fromherz, J. Phys. Chem. B 105 (2001) 343. [3] D. Täuber, I. Trenkmann, and C. von Borczyskowski, Langmuir 29 (2013) 3583. [4] B. Schulz, D. Täuber, C. von Borczyskowski et al., Soft Matter 7 (2011) 7431.