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MM: Fachverband Metall- und Materialphysik

MM 24: Nano structured materials II

MM 24.5: Vortrag

Mittwoch, 28. März 2007, 17:45–18:00, H4

Platinum deposition on polyethylene films investigated by molecular dynamics — •Thomas Kraska and Roberto Rozas — Institute for Physical Chemistry, University Cologne, Luxemburger Str. 116, 50939 Köln, Germany

The growth mechanisms of platinum clusters on and in a polyethylene film is investigated by molecular dynamics simulation. This system has been chosen as a model system with a relatively simple polymer. Platinum is modelled by the embedded atom method and polyethylene by a united atom model with flexible bonds, angle potential, and torsion potential for the intramolecular two-, three-, and four-body interactions. The intermolecular interaction is modelled by a Lennard Jones potential. Furthermore argon is added as carrier gas which removes heat from the vapour phase by collision with the platinum atoms and the polymer surface. An equilibrated polyethylene film is set in the middle of a rectangular box. The gas phase volume of the box is filled with platinum and argon atoms. Once the simulation is started clusters form in the vapour phase as well as on and in the polyethylene film.

Simulations at different platinum vapour phase densities are analysed with respect to the growth mechanism. General agreement is found with metal/polymer systems investigated experimentally in the literature. At higher platinum supersaturation less platinum diffuses into the polymer film. This is due to homogeneous nucleation the vapour phase leading to large clusters, which less likely diffuse into the polymer.