J. Phys. II France
Volume 4, Number 10, October 1994
Page(s) 1763 - 1769
DOI: 10.1051/jp2:1994110
J. Phys. II France 4 (1994) 1763-1769

Demixing in a hard rod-plate mixture

René van Roij and Bela Mulder

FOM-Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands

(Received 5 April 1994, accepted 1 July 1994)

We argue that the possibility to observe a stable biaxial nematic phase in a binary mixture of prolate and oblate hard particles is seriously limited by the existence of entropydriven demixing. This result follows from a simple Onsager-type density functional theory. An important feature is the coupling of the demixing mechanism to the orientational order of the system. The strength of this coupling is dependent on the asphericity of the particles, and is directly related to the stability of the biaxial nematic phase.

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