Berlin 2008 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: POSTERS Rheology
CPP 7.26: Poster
Monday, February 25, 2008, 16:45–19:00, Poster A
Micellar crystallization in salted solutions — •Nicole Voss1, Marco Walz1, Max Wolff2, Hartmut Zabel2, and Andreas Magerl1 — 1Chair for Crystallography and Structural Physics, University of Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen — 2Chair for Condensed Matter Physics, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum
Micellar solutions of tri-block copolymers are an excellent model system for the study of crystallization in soft matter, since they have well-known and rich phase diagrams which may be identified through rheometry. The phases can be controlled by varying temperature or polymer concentration. Further, the aggregation and crystallization is highly sensitive to the presence of ions. Through the addition of salt the attraction between hydrocarbon chains and water can be tuned allowing a study of the macromolecule-solvent interaction.
We have studied the influence of CsCl with concentrations up to 1.5 mol/dm3 on the phase diagram of the tri-block copolymer Pluronic P123, consisting of a central part of 70 propylene oxide units terminated by two end groups of 20 ethylene oxide units (EO20–PO70–EO20). The salient result of our investigation is a linear shift of all phase lines to lower temperatures under the addition of salt, whereas the fundamental structural properties of the phases are preserved.
The work was in part supported by the DFG priority program SPP 1164.