Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Polymerphysics II
CPP 30.7: Vortrag
Donnerstag, 28. Februar 2008, 15:45–16:00, C 130
Influence of Electric Fields on the Phase Behavior of Concentrated Block Copolymer Solutions — •Heiko G. Schoberth1, Kristin Schmidt2, and Alexander Böker1 — 1Physikalische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany — 2Materials Research Laboratory, University of California, Santa Barbara, USA
We investigate the influence of the electric field on the phase behavior of diblock copolymer morphologies in concentrated solutions using Synchrotron SAXS. We observe a decrease of the order-disorder-transition temperature and phase separation with increasing electric field strength. This shift is found in TODT even at moderate field strengths and follows a linear dependence.
Furthermore we can also induce an order-order-transition. We synthesized different block copolymers with compositions close to the predicted phase boundaries. Due to the lower free energy of aligned anisotropic microdomain structures parallel to the electric field, we can induce a transition from the metastable hexagonally perforated lamellae to the lamellae phase under strong electric fields. In addition for an isotropic cubic gyroid phase, which cannot be aligned, a transition to aligned cylinders is found.