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Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 12: POSTER Colloids, Nanoparticles and Self-Organizing Systems

CPP 12.14: Poster

Tuesday, March 28, 2006, 17:00–19:00, P3

Electric Field induced Effects on the Microdomains in Concentrated Block Copolymer Solutions — •Kristin Schmidt1, Heiko Schoberth1, Thomas M. Weiss2, Volker Urban3, Peter Lindner4, Alexander Böker1, and Georg Krausch11Lehrstuhl für Physikalische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany — 2European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble, France — 3Oak Ridge National Laboratory (ORNL), Oak Ridge, TN-37831, USA — 4Institut Laue Langevin (ILL), F-38043 Grenoble, France

We investigate the microscopic mechanism of reorientation of concentrated block copolymer solutions exposed to an electric field by time-resolved synchrotron small-angle X-ray scattering (SAXS). As a model system, we use a lamellar polystyrene-b-polyisoprene block copolymer dissolved in toluene. The underlying mechanism at the level of individual macromolecules is studied by small-angle neutron scattering (SANS). Depending on the electric field strength we observe a decrease of the lamellar distance of lamellae orientated parallel to the E-field. Through the parallel orientation of the lamellar plane, the polymer backbones orient perpendicular to the E-field lines. We therefore expect that the diblock chains exhibit a certain degree of stretching. Hence, we study the single-chain form factor of the copolymer exposed to an electric field.

In addition, we observe an influence of the electric field on the order disorder temperature and phase separation in our block copolymer solutions. We found a significant shift in TODT at moderate field strengths. For further investigations we study this effect by birefringence.

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