Regensburg 2007 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 26: INTERNAL SYMPOSIUM Optical Spectroscopy I

CPP 26.7: Talk

Thursday, March 29, 2007, 12:15–12:30, H40

Single-molecule traffic in mesoporous materials — •Christophe Jung, Johanna Kirstein, Timo Lebold, Jens Michaelis, and Christoph Bräuchle — LMU, München

In the last decade single molecule methods play a major role in material science because they can reveal structural and dynamic features which are otherwise obscured by ensemble averaging in conventional spectroscopic methods. Here we show how single dye molecules can be used as nanoscale probes to map out the structure of mesoporous thin films, and to provide valuable insight into the dynamics/interactions of guests molecules within the host porous matrix. In a first study, the translational and orientational movement of single TDI molecules was observed simultaneously in CTAB templated films with hexagonal pores (M41S). The molecules show linear movement, with their transition dipole moment aligned along their trajectories, reflecting the structural features of the underlying material, i.e. unidimensional, straight, cylindrical pores. A second system containing a mixture of hexagonal and lamellar phase was obtained using the non-ionic Block-copolymer Brij-56 as template. The structure of the trajectories, the diffusivities and the orientation of single molecules are distinctive for molecules travelling in the hexagonal and the lamellar mesophases. Moreover, transitions between the different types of surroundings can be observed for the same individual dye molecule.