The Flory Lattice Model of Nematic Fluids

The Flory lattice theory of neat nematic fluids is reviewed and compared to other current statistical-mechanical treatments of systems of ordered hard rods. It is shown that the model provides a sound description of the nematic state. At intermediate concentrations the free energy derived thereby reduces to the expression given by the decoupling approximation.1 At low concentrations the result of the Onsager Theory is obtained. The Flory theory is easily extended to include thermotropic systems by introducing the characteristic temperature of anisotropic interaction T*. This parameter is in semi-quantitative agreement with values estimated from optical and thermodynamic data.