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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.61: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Reorientation of the Microdomains in Concentrated Block Copolymer Solutions using AC/DC Electric Fields — •Kristin Schmidt¹, Heiko Zettl¹, Frank Schubert¹, Helmut Hänsel¹, Franz Fischer², Thomas M. Weiss³, Alexander Böker¹, and Georg Krausch¹ — ¹Lehrstuhl für Physikalische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany — ²Lehrstuhl für Kristallographie, Universität Bayreuth, D-95440 Bayreuth, Germany — ³European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble, France

We investigate the microdomain structure 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 polystyrene-b-polyisoprene block copolymer dissolved in toluene. We study the mechanism of reorientation of block copolymers with different microdomain structures (lamellar and cylindric) using a DC field.

Depending on the polymer concentration and the initial degree of order we identify two different microscopic mechanisms which dominate the orientation process, i.e. nucleation and growth of domains and grain rotation.

In addition, we study the frequency dependence of the reorientation of our block copolymer systems in AC electric fields. For example, we find reorientation at 150 Hz, which allows us to exclude any influence of migration of ions in the block copolymer solutions.