Synthesis and properties in solution of rodlike polyelectrolytes |
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Authors: | Matthias Ballauff Jürgen Blaul Birgit Guilleaume Matthias Rehahn Steffen Traser Matthias Wittemann Patrick Wittmeyer |
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Institution: | 1. Polymer Institute, University of Karlsruhe, Kaiserstrasse 12, D-76128 Karlsruhe, Germany;2. Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany |
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Abstract: | Efficient synthetic strategies are described for the preparation of rodlike polyelectrolytes based on the intrinsically rigid poly(p-phenylene). Uncharged precursors were first prepared via the Suzuki coupling and then characterized by different methods of polymer analysis. Finally, they were transformed into polyelectrolytes using macromolecular substitution reactions. Depending on the substitution pattern, the obtained polyelectrolytes are either soluble or insoluble in water. Using water-soluble derivatives, the Poisson-Boltzmann cell model was tested by osmotic measurements and small-angle X-ray scattering. It is shown that the cell model provides a good first approximation of the distribution of the counterions around the macroion but still underestimates their correlation. Moreover, the PPP polyelectrolytes show a very pronounced polyelectrolyte effect. Since the rodlike PPPs are very rigid in shape, this observation proves that the polyelectrolyte effect is caused by long-range intermolecular electrostatic repulsion of the dissolved macroions rather than due to conformational changes. |
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Keywords: | cell model counterion condensation osmotic coefficient polyelectrolytes rodlike polymers |
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