Regensburg 2004 – wissenschaftliches Programm
O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)
O 14.50: Poster
Montag, 8. März 2004, 18:00–21:00, Bereich C
Surface dynamics of gold clusters on thin polymer films investigated by XPCS — •Virginie Chamard1, Markus Krämer1, Christian Gutt1, Anders Madsen2, and Metin Tolan1 — 1Experimentelle Physik I, Universität Dortmund, 44221 Dortmund — 2ESRF, Grenbole, France
Using the technique of X-Ray Photon Correlation Spectroscopy (XPCS) it is possible to observe dynamics at low frequencies (from 106 s−1 to 10−3 s−1) and small lengthscales of micro- to nanometers, which are not or hardly accessible to other techniques.
In the present work we examined the dynamics of thin polymer films covered with nanometer sized gold clusters. We performed intensity-intensity autocorrelation measurements of the samples at different temperatures. If the sample is heated to temperatures higher than the glass transition temperature of the polymer, the clusters sink inside to a position a few Å below the surface. There they act as markers for the capillary wave movement of the surrounding polystyrene. Furthermore the clusters perform a Brownian Motion inside the polymer which can, as well as the capillary waves, be characterized by correlation measurements. The resulting viscosity is several orders of magnitude higher than the viscosity of pure polymer systems without gold. In addition it has been found that the viscosity of the gold/polymer system is less temperature dependent than that of the polymer.