Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Single Molecules

CPP 15.8: Vortrag

Dienstag, 26. Februar 2008, 18:45–19:00, C 230

Visualizing single molecule diffusion in nanoporous materials — •Christophe Jung, Johanna Kirstein, Andreas Zürner, Babara Platschek, Thomas Bein, and Christoph Bräuchle — Department of Chemistry and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Butenandtstrasse 11, 81377 München

Nanostructured host-guest materials are important for various applications (e.g. catalysis, molecular sieving, drug-delivery systems). Therefore a thorough understanding of the dynamics and the interactions of the guest molecules inside the host matrix is needed. Whereas measurements of ensemble diffusion provide information about the overall behaviour of the guests in a porous host, tracking individual molecules provides insights into heterogeneities, mechanistic details of molecular diffusion and the host structure. Thin mesoporous silica films containing a hexagonal and lamellar phase mixture were investigated. The dye molecules act as beacons while they diffuse through the different structural phases of the host: the structure of the trajectories, the diffusivities and the orientation of single molecules are distinctive characteristics, for molecules travelling in each mesophase or on the film surface. Moreover, we combine single molecule microscopy techniques with transmission electron microscopy in order to directly correlate individual molecular trajectories with the underlying structure of the porous host. It can be investigated in great detail how the luminescent molecule diffuses within the mesoporous channel system, how it changes speed, direction or traffic lanes in the porous network.