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DY: Dynamik und Statistische Physik

DY 34: Poster

DY 34.9: Poster

Montag, 7. März 2005, 15:30–18:00, Poster TU D

On the theory of the shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers — •Patrick Ilg and Siegfried Hess — Institut für Theoretische Physik, Technische Universität Berlin

The shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers is studied theoretically. A modification of previous models of main-chain liquid crystals [1] to the case of side chain liquid-crystalline polymers is proposed. Orientational and rheological properties of the model are studied in plane shear flow [2].

It is found that the coupling of the mesogenic side chains to the polymer back bone modifies the dynamical properties considerably. For example the shear-induced isotropic-to-nematic transition is shifted compared to ordinary nematics and liquid crystals. Due to the different relaxation times of the side chains and the polymer back bone, a stress plateau is observed. Predictions of the present model agree qualitatively with experimental results [3].

[1] S. Hess, Z. Naturforsch. 31a, 1507 (1976). [2] S. Hess, P. Ilg, submitted to Rheol. Acta. [3] C. Pujolle-Robic, L. Noirez, Nature 409, 167 (2001).