Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Polyelectrolytes

CPP 17.1: Hauptvortrag

Dienstag, 8. März 2016, 09:30–10:00, H40

Molecular Dynamics Simulations of Compacted Polyelectrolyte Complexes — •Diddo Diddens, Jörg Baschnagel, and Albert Johner — Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 23 Rue du Loess, 67034 Strasbourg Cedex 2, France

Compacted polyelectrolyte complexes (CoPECs) are gel-like materials created by ultracentrifugation [1] or extrusion [2] from solution-precipitated polyelectrolyte complexes. Usually, polyelectrolyte complexes have an ill-defined microscopic structure due to the fast aggregation kinetics of polyanions and polycations, which prevents the formation of an optimized ion pairing between positive and negative charges. Here, the two experimental strategies mentioned above offer a novel route to densify/reshape the complexes, which is difficult to achieve otherwise. However, although it is known from micrograph imaging that the CoPECs are highly porous, the precise effect of the centrifugation/extrusion on the polymer matrix is less clear.

We address this issue by mimicking the experimental centrifugation protocol in a fully atomistic Molecular Dynamics simulation. In particular, we identify the structural and dynamical changes during the individual stages of the compaction, which includes sedimentation, subsequent compression at the boundary and the behavior after centrifugation. These findings are discussed in context with the experimental observations.

[1] Porcel, Schlenoff, Biomacromolecules, 2009, 10, 2968

[2] Shamoun, Reisch, Schlenoff, Adv. Funct. Mater., 2012, 22, 1923