Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.27: Poster

Freitag, 4. März 2005, 17:15–19:00, Poster TU D

Magnetic Field Induced Orientation in Diblock Copolymers with One Crystallizable Block — •T. Grigorova¹, S. Pispas², T. Thurn-Albrecht¹, and N. Hadjichristidis² — ¹FB Physik, Martin-Luther Universität Halle-Wittenberg, 06120 Halle (Saale), Germany — ²Department of Chemistry, University of Athens, 15784 Ilissia, Greece

Crystallization of semicrystalline polymers in a strong magnetic field under appropriate thermal conditions leads to the formation of an oriented texture. We have applied that effect to induce orientation in semicrystalline block copolymers and show that asymmetric PEO-b-PB copolymers can be easily aligned if the crystallization starts from a disordered state. Necessary condition is that the crystallization starts from a high number of nuclei. The magnetic field can induce orientation only during the initial stage of the spherulitic growth before branching of crystallites takes place. The orientation of the crystallites, observed with wide angle X-ray scattering, goes along with the orientation of the block copolymer microphase structure. The resulting lamellar structure is oriented with the lamellar normal parallel to the direction of the applied field (negative order parameter), similarly as for electric field induced orientation in purely amorphous diblock copolymers.