Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 31: Organische Dünnschichten II

O 31.5: Vortrag

Donnerstag, 27. März 2003, 16:00–16:15, HSZ/02

Two-dimensional aggregation of species with weak and strong bonding interactions: Modelling the growth of a self-assembled alkylsiloxane monolayer — •Rafael Bautista, Nils Hartmann, and Eckart Hasselbrink — Fachbereich Chemie, Universität Essen, Universitätsstraße 5, 45141 Essen, Germany

A simple-generalized two-dimensional model for kinetic Monte Carlo (KMC) simulations of the growth of a self-assembled alkylsiloxane monolayer on oxidized substrates is suggested, which, for the first time, takes the laterally and vertically operating weak and strong bonding interactions of the aggregating species into account. The model is based on a general reaction mechanism including the adsorption, diffusion, vertical grafting and lateral cross-linking of preordered alkylsilanol clusters. All model parameters are adjusted to experimental estimates. Despite the simplicity of the model, the simulation results qualitatively reproduce many morphological aspects of the experimentally observed island growth and provide a simple explanation for the deviations from first-order Langmuir adsorption kinetics reported in various ex situ investigations [1, 2].

[1] Th. Balgar, R. Bautista, N. Hartmann and E. Hasselbrink, Surf. Sci.,ECOSS-21 Proceedings, accepted.

[2] J. V. Davidovits, V. Pho, P. Silberzan and M. Goldmann, Surf. Sci. 352-354 (1996) 369.