Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 68: Poster: Complex Fluids, Glasses, Granular

DY 68.13: Poster

Donnerstag, 15. März 2018, 15:30–18:00, Poster A

Concentration effects on the phase-behaviour and sheared dynamics of rod-like particles — •Pawel Mollenhauer, Henning Reinken, and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Berlin, Deutschland

Already in thermodynamic equilibrium, systems of rod-like particles show an interesting phase behavior, including isotropic–nematic phase coexistence. Driving such a system out of equilibrium by applying a shear flow results in a shift of the isotropic–nematic transition. Furthermore, sheared nematic liquid crystalline systems can show the formation of bands in the gradient and the vorticity direction [1]. These spatial patterns can additionally feature oscillatory orientational motion of the nematic director (e.g. tumbling or wagging) [2].

In this work, we apply the Doi-Hess-theory [3] that couples the tensorial nematic order parameter to the velocity field. In addition, we explicitly include the concentration dynamics using a DFT-approach bridging microscopic and mesoscopic levels [4]. Starting from an already phase-separated system we numerically investigate the spatiotemporal pattern formation under shear. In contrast to earlier works [5], we do not restrict our investigations to stationary states. Instead, we focus on oscillatory states and vorticity banding.

[1] P. Olmsted, Rheol. Acta 47: 283 (2008).
[2] R. Lugo-Frías et al., Eur. Phys. J. E 39: 88 (2016).
[3] S. Hess, Tensor for Physics, (2015).
[4] R. Lugo-Frías et al., J. Phys.: Condens. Matter 28, 244022 (2016).
[5] P. Olmsted et al., Phys. Rev. E 60, 4 (1999).