Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Poster: Charged Soft Matter
CPP 33.14: Poster
Mittwoch, 13. März 2013, 16:30–18:30, Poster C
molecular dynamics simulations of polyeletrolyte brushes under poor solvent conditions — •guili he1, holger merlitz2, and jens-uwe sommer1 — 1Leibniz-Institut fuer Polymerforschung Dresden, 01069 Dresden, Germany — 2Department of Physics and ITPA, Xiamen University, Xiamen 361005, P.R. China
Molecular dynamics simulations have been applied to investigate salt-free planar polyelectrolyte brushes under poor solvent conditions with respect to the molecular backbone under the variation of the chain degree of polymerization, the brush grafting density and the charge fraction (strength of the electrostatic interaction). We found that, with decreasing the system temperature (changing solvent quality) far below the theta point, the brush first displays lateral phase separation with respect to the solvent and eventually collapses vertically [see also J.-M. Y. Carrillo and A. V. Dobrynin, Langmuir 2009, 25(22)]. The lateral phase separation leads to cylindrical morphologies (bundles of chains) which has been observed for different charge fraction, degree of polymerization and grafting density. Even changing the size and solvent selectivity of the counterions cannot prevent lateral structure formation in the poor solvent state. This phenomenon can be explained by an entropy gain of counterions in the cylindrical state as compared to the homogeneously collapsed state at the same temperature.