Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: POSTERS Single Molecules, Biopolymers, Membranes
CPP 9.26: Poster
Montag, 25. Februar 2008, 16:45–19:00, Poster A
Heterogeneous nucleation and growth of high wettable systems studied by molecular dynamics simulations — •Roberto Rozas1,2 and Thomas Kraska2 — 1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt, Linder Höhe, D-51147 Köln — 2Institut für Physikalische Chemie, Universität zu Köln, Luxemburger Str. 116, D-50939 Köln
Heterogeneous nucleation and growth of supersaturated argon vapor at polyethylene surfaces is investigated by molecular dynamics simulations. The system serves as a model for high wettable systems. A non-equilibrium ensemble which allows the development of gradients in the system is employed; Nosé-Hoover thermostat is applied to the polymer substrate only while the vapor condenses. Simulations along an isotherm at different initial saturation of the vapor indicate a transition, close to the binodal, from adsorption to heterogeneous nucleation. At moderate saturation the layer-by-layer growth mechanism dominates while at higher supersaturation a tendency to growth islands-on-layers growth is observed. We find for this system that a two-dimensional version of the classical heterogeneous nucleation theory (HEN2D) is most suitable to describe the nucleation rate data versus saturation obtained from simulation.