Shape matters - Two stories about colloidal liquid crystals

Tanja Schilling

Johannes-Gutenberg-Universität Mainz, Institut für Physik, Mainz, Germany

We present computer simulation studies of several effects caused by particle anisotropy in colloidal suspensions.

Coexistence between the isotropic and the nematic phase in suspensions of rods is studied using grand canonical Monte Carlo simulations with a bias on the nematic order parameter. The new biasing scheme makes it possible to estimate the interfacial tension rather accurately. Then we show results of a Monte Carlo study of the capillary waves on the interface. In agreement with recent theoretical investigations we find a strongly anistropic capillary wave spectrum. For the wave-numbers accessed in our simulations, the spectrum is quadratic, i. e. elasticity does not play a role.

The second part of the presentation deals with the phase diagramme of hard ellipsoids. Contrary to previous studies we find a very rich variety of crystalline phases.

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