Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 40: Colloids and Complex Liquids III

CPP 40.3: Talk

Thursday, April 3, 2014, 11:45–12:00, ZEU 260

Fundamental measure approaches to liquid crystals — •René Wittmann, Matthieu Marechal, and Klaus Mecke — Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany

Fluids of hard spherocylinders exhibit a rich phase behavior including isotropic, nematic and smectic-A phases. A density functional for anisotropic hard bodies can be constructed in terms of tensorial weighted densities (FMT) which depend on geometry and position of only one single oriented particle [1]. Within a new geometric method to derive the exact low-density functional we introduce a mixed measure of two bodies which can be expanded to the original tensor series. We compare this fundamental mixed measure theory (FMMT) to approximated results and Monte-Carlo simulations.
Closed formulas for the Frank elastic coefficients and the restriction to parallel spherocylinders verify the consistency of FMMT analytically. The isotropic - nematic interfacial tension remarkably improves on earlier, only qualitatively correct predictions [2]. For the first time we obtain a phase diagram of hard spherocylinders which can be quantitatively compared to simulations. We find a first order nematic to smectic-A transition up to an aspect ratio of at least 40. The increased computational effort and the relevance of other components of the functional is discussed.
[1] H. Hansen-Goos and K. Mecke, Phys. Rev. Lett. 102, 018302 (2009).
[2] R. Wittmann and K. Mecke, J. Chem. Phys., submitted (2013).