title: Statistical models of mixtures with a biaxial nematic phase.
abstract: 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.
authors.affiliation: Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970 São Paulo, SP, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: do Carmo
authors.forename: D B
authors.initials: DB
authors.lastname: Liarte
authors.forename: S R
authors.initials: SR
authors.lastname: Salinas