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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Poster: Interfaces and Thin Films

CPP 14.12: Poster

Monday, March 22, 2010, 16:30–18:00, Poster C

Interfacial effects on single dye diffusion in ultrathin liquid films — •Daniela Täuber, Frank Gerlach, Sebastian Schubert, and Christian von Borczyskowski — TU-Chemnitz, Institut für Physik, 09107 Chemnitz, and FOR 877

Liquids show layering at solid-liquid interfaces [1], which leads to dynamic heterogeneity in diffusion. Recent observations show additional influence of static heterogeneities of the interface on diffusion.

Here we used Rhodamines to trace the diffusion in ultrathin liquid (TEHOS) films on Si wafers with thermally grown oxide via optical single molecule tracking. Long term observations on thinning films reveal that there is no change in diffusion down to three molecular diameters from the substrate [2]. On the other hand modification of the silanol density on the substrate influenced the fraction of near surface diffusion. Enhancement of diffusion was correlated with the silanol cluster size (ca 0.5 microns) on the heterogeneous substrate.

[1] C.-J. Yu et al: , Phys. Rev. Lett. 82 (1999) 2326-29

[2] D. Täuber, C. von Borczyskowski et al: Diff. Fund. J. 12 (2009) accepted