Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: POSTERS Polymerphysics

CPP 34.54: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Influence of solvent and counterion on the effective charge and size of polyelectrolytes — •Ute Böhme and Ulrich Scheler — Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden, Germany

The effective charge of polyelectrolytes in mixtures of organic solvents and water is primarily governed by the permittivity. Decreasing the dielectric constant leads to stronger charge- charge interaction on the polyelectrolyte resulting in enhanced counterion condensation and thus reduced effective charge. A combination of diffusion and electrophoresis NMR is applied to determine the effective charge of polyelectrolytes with different monovalent counterions in polar solvents adjusting permittivity by water content [1,2].

In solvents with high water fraction the charge decreases linearly with the permittivity while in mixtures with low water content the effective charge and size of the polyelectrolyte drops dramatically depending on the counterion. Reduced repulsive interactions between the charges along the chain lead to a more compact conformation of the polyelectrolyte.

[1] U. Scheler in H.S. Nalwa (ed.): Handbook of Polyelectrolytes and their applications, American Scientific Publishers (2002), Vol.2

[2] U. Böhme, U. Scheler, J. Colloid Interface Sci., 309, (2007), 231.