On the phase equilibria of nematic mixtures

The theory of Brochard et al. for mixtures of nematogens is applied to the case of crosslinked polymers with side chain liquid crystals and low- molec ular-weight liquid crystals. Phase equilibria of those mixtures are analyze d by allowing the Flory-Huggins interaction parameter for isotropic mixture and the rubber elasticity parameters of the elastic network, to be functio ns of the polymer volume fraction. A wide range of crosslinking density is covered showing a strong influence on the phase behavior of such compounds. The clearing temperature of nematic-isotropic transition of each nematogen is different and the cross-nematic interaction parameter is a geometric av erage of the parameters for pure nematogens. (C) 2000 John Wiley & Sons, In c.