Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 17: Thin Films and Surfaces II
CPP 17.7: Vortrag
Mittwoch, 29. März 2006, 17:15–17:30, ZEU Lich
Irreversible adsorption of tethered chains at substrates. Monte Carlo Study. — •Radu Descas1,2, Jens-Uwe Sommer2, and Alexander Blumen1 — 1Theoretische Polymerphysik, Universität Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany — 2Institut de Chimie des Surfaces et Interfaces, 15, rue Jean Starcky, F-68057 Mulhouse Cedex, France
We study using the bond fluctuation model the irreversible adsorption of single chains grafted with one end to the surface [1]. While the reversible adsorption involves equilibrium states [2,3], the irreversible adsorption implies non-equilibrium ones. We find that the adsorbate’s growth is dominated by the zipping of monomers according to their order along the chain. The time of adsorption t(M) as a function of the number M of adsorbed monomers follows a power law; Mα with α > 1. We introduce a two-phase model, in which the chain is described by an adsorbate portion and a corona. According to our model the adsorption can be viewed as consisting in a main stage, during which single monomers attach to the surface through zipping, and a late stage, in which the corona collapses on the surface. We find that α is given by α = 1+ν, where ν is the Flory exponent, and study the time evolution of various density profiles.
[1] R Descas, J. -U. Sommer and A. Blumen, submitted.
[2] R Descas, J. -U. Sommer and A. Blumen, J. Chem. Phys. 120, 8831, (2004).
[3] R Descas, J. -U. Sommer and A. Blumen, J. Chem. Phys. 122, 134903, (2005).