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CPP: Chemische Physik und Polymerphysik

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

CPP 12.14: Poster

Dienstag, 28. März 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 Krausch¹ — ¹Lehrstuhl 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 T_ODT at moderate field strengths. For further investigations we study this effect by birefringence.