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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: POSTERS Micro- and Nanofluidics

CPP 22.15: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

Single Molecule Diffusion on Chemically patterned Substrates — •Martin Pumpa and Frank Cichos — Molecular Nanophotonics Group, University Leipzig

Molecular dynamics at solid/liquid interfaces is defined by the strength of the interaction of the liquid with the solid surface. This interfacial region extendes serveral 10 nm into the liquid, where modified structure and dynamics appear i.e. in the form of liquid layering. Thus control of the surface properties of a solid substrate provides a route to control the interfacial molecular dynamics in liquid films. Within this contribution, we present first experimental results on a controlled manipulation of single molecule diffusion by chemically patterning glass surfaces. Using micro-contact printing, we prepare a hydrophilic/hydrophobic pattern on the surface. Typical dimensions of the structure of this pattern are on the order of a few micrometers. These surfaces are either covered by an ultrathin liquid film or mounted in a surface forces apparatus, where the liquid covering the pattern is confined down to a film thickness of a few 10 nanometers. To study molecular dynamics, we employ single molecule tracking of dye molecules dissolved in the liquid. The diffusion of these dye molecules is observed by fluorescence wide field microscopy. First indications of anisotropic diffusion due to the pattern structure are reported.