Statistical models of mixtures with a biaxial nematic phase.
We consider a simple Maier-Saupe statistical model with the inclusion of disorder degrees of freedom to mimic the phase diagram of a mixture of rodlike and disklike molecules. A quenched distribution of shapes leads to a phase diagram with two uniaxial and a biaxial nematic structure. A thermalized distribution, however, which is more adequate to liquid mixtures, precludes the stability of this biaxial phase. We then use a two-temperature formalism, and assume a separation of relaxation times, to show that a partial degree of annealing is already sufficient to stabilize a biaxial nematic structure.
do Carmo
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Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970 São Paulo, SP, Brazil.
Liarte
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Salinas
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