Density minimum in the isotropic-nematic transition of hard cut-spheres

Fartaria, Rui P.S. and Sweatman, M.B. (2009) Density minimum in the isotropic-nematic transition of hard cut-spheres. Chemical Physics Letters, 478 (4-6). pp. 150-154. ISSN 0009-2614 (https://doi.org/10.1016/j.cplett.2009.07.047)

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Abstract

We study the isotropic-nematic transition of hard cut-spheres over a wide range of aspect ratios using Monte Carlo simulation and umbrella sampling. We find a minimum in the density of both coexisting phases near to L/D=0.04 (thickness/diameter) and show that this minimum is a result of competition between the solid volume of the disks and the free volume which is significantly influenced by nematic pre-ordering in the isotropic phase. We expect similar behaviour for other kinds of discotic particles. This behaviour should be observed as a kind of 'partially re-entrant' isotropic phase for discotic mesogens within an appropriate concentration range.