Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 20: POSTER A

CPP 20.6: Poster

Montag, 24. März 2003, 19:00–21:00, ZEU/250

Thermal Composition Fluctuations and Phase Behavior of an A/B/A-B Homopolymer Blend/Diblock Copolymer Mixture — •Vitaliy Pipich, Dietmar Schwahn, and Lutz Willner — Institut für Festkörperforschung, Forschungszentrum Jülich GmbH

Thermal composition fluctuations were explored with SANS in a homopolymer blend dPB/PS of critical composition mixed with different amounts of a symmetric diblock copolymer dPB-PS [dPB and PS being deuterated polybutadiene and polystyrene, respectively]. Phase boundaries of various ordered phases including two critical universality classes and the Lifshitz line (LL) were determined. Strong thermal fluctuations lead to a non-monotonic LL, droplet and bicontinuous microemulsion phases, and a reentrant two-phase region near LL with an upper and lower critical solution temperature and a double critical point (DCP). The expected doubling of the Lifshitz critical exponent was observed approaching the DCP.