Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: POSTERS Rheology

CPP 7.1: Poster

Montag, 25. Februar 2008, 16:45–19:00, Poster A

Spatio-temporal behavior of dipolar nano-rods under shear — •Sebastian Heidenreich, Siegfried Hess, and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergst. 36, D-10623

The flow properties of nano-rods are strongly affected by the dynamical behavior of molecular alignment. A theoretical description can be made by an relaxation equation [1] of the order parameter tensor. For plane Couette flow geometry the model leads to a rather complex orientational and flow behavior [2]. Depending on the model parameters and the boundary conditions various flows like shear banding flow can occur. To describe suspensions consisting of dipolar nano-rods that can form clusters with an effective polarization the relaxation equation has to be extended. In [4] the coupling of the orientation and the dipole moment was investigated for the bulk system. The additional dipole moment strongly affects the orientational dynamics. In this contribution we study a spatially inhomogeneous tensor model. In the plane Couette geometry structure emerges in the flow profile not known from the flow behavior of nano-rods without dipole moments. Furthermore, we present the effect of the dipole moment on the start up flow dynamics of shear bands.
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B. Chakrabarti, M. Das, C. Dasgupta, S. Ramaswamy, and A. K. Sood, Phys. Rev. Lett. 92, 055501,(2004);
S. Grandner, S. Heidenreich, P. Ilg S. H. L. Klapp, and S. Hess; S. Grandner, S. Heidenreich, S. Hess, and S. H. L. Klapp, EPJE in press