Regensburg 2004 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 14: SYMPOSIUM: Understanding and Controlling Complex Structures: From Synthetic Polymers to Biomaterials II

CPP 14.8: Talk

Tuesday, March 9, 2004, 16:30–16:45, H 37

Monte Carlo Simulations of the phase behaviour of polymer brushes — •Ludger Wenning, Marcus Müller, and Kurt Binder — Johannes Gutenberg Universität Mainz

A polymer brush in a poor solvent is investigated by Monte Carlo (MC) simulations of a bead-spring-model.

A new MC-Move for the inner part of a polymer chain has been devised to efficiently equilibrate the chain conformations. This move is based on the Configurational Bias (CB) algorithm, but in contrast to the CB-move it needs no free end of the polymer chain. Therefore it works for grafted polymers or ring polymers.

We observe the transition from a swollen, homogenous brush in a good solvent to a laterally structured cluster phase in a bad solvent. This transition depends on the solvent quality and the surface coverage. Unlike the prediction of self-consistent field theory, clusters do not form a hexagonal lattice, but rather arrange irregularly.

Further the influence of the way of grafting is studied. Random grafting leads to slightly larger clusters, which are also more stable at better solvent quality. Moreover we demonstrate how the locations of the clusters correlate with density fluctuations in the grafting points.