%0 Journal Article
%T Energetic and Entropic Contributions to the Landau每de Gennes Potential for Gay每Berne Models of Liquid Crystals
%A Bhaskar Gupta
%A Patrick Ilg
%J Polymers
%D 2013
%I MDPI AG
%R 10.3390/polym5020328
%X The Landau每de Gennes theory provides a successful macroscopic description of nematics. Cornerstone of this theory is a phenomenological expression for the effective free energy as a function of the orientational order parameter. Here, we show how such a macroscopic Landau每de Gennes free energy can systematically be constructed for a microscopic model of liquid crystals formed by interacting mesogens. For the specific example of the Gay每Berne model, we obtain an enhanced free energy that reduces to the familiar Landau每de Gennes expression in the limit of weak ordering. By carefully separating energetic and entropic contributions to the free energy, our approach reconciles the two traditional views on the isotropic每nematic transition of Maier每Saupe and Onsager, attributing the driving mechanism to attractive interactions and entropic effects, respectively.
%K liquid crystals
%K Landau每de Gennes potential
%K coarse graining
%U http://www.mdpi.com/2073-4360/5/2/328