Mesophase formation in a system of top-shaped hard molecules: Density functional theory and Monte Carlo simulation

Autor(en)

Daniel De Las Heras, Szabolcs Varga, Franz Vesely

Abstrakt

We present the phase diagram of a system of mesogenic top-shaped molecules based on the Parsons-Lee density functional theory and Monte Carlo simulation. The molecules are modeled as a hard spherocylinder with a hard sphere embedded in its center. The stability of five different phases is studied, namely, isotropic, nematic, smectic A, smectic C, and columnar phases. The positionally ordered phases are investigated only for the case of parallel alignment. It is found that the central spherical unit destabilizes the nematic with respect to the isotropic phase, while increasing the length of the cylinder has the opposite effect. Also, the central hard sphere has a strong destabilizing effect on the smectic A phase, due the inefficient packing of the molecules into layers. For large hard sphere units the smectic A phase is completely replaced by a smectic C structure. The columnar phase is first stabilized with increasing diameter of the central unit, but for very large hard sphere units it becomes less stable again. The density functional results are in good agreement with the simulations.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Universidade Nova de Lisboa, University of Pannonia

Journal

Journal of Chemical Physics

Band

134

Anzahl der Seiten

9

ISSN

0021-9606

DOI

https://doi.org/10.1063/1.3596749

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/30fc0af4-d2dd-4b4b-9c69-836eaae8b90a