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SYPE: Symposium Polyelectrolytes

SYPE 3: Polyelectrolytes II

SYPE 3.2: Talk

Friday, March 30, 2007, 11:00–11:15, H1

Polyelectrolyte complexes and effective charge — Ute Böhme Böhme and •Ulrich Scheler — Leibniz-Institut für Polymerforschung Dresden, e.V., Hohe Str. 6, D-01069 Dresden

Condensation of counterions onto polyelectrolytes is directly monitored in diffusion and electrophoresis NMR. From a combination of both experiments the effective charge per molecule is determined. The diffusion coefficient and electrophoretic mobility measured for counteions or small ligands is the population-weighted average of the values for the free and the bound state, the later corresponding to that of the polymer. Knowing both values, the bound fraction of counterions is calculated, from which with the effective charge the molecular weight of the polymer is determined model free. Binding of ligands and the formation of polyelectrolyte complexes is investigated with an emphasis on weak binding and the equilibrium states. Examples shown include flexible polyelectrolyte like PDADMAC and PSS and rigid-rod poly(aramides).