MONODISPERSE POLYMER LIQUID-CRYSTALS NEAR THE ANISOTROPIC ISOTROPIC TRANSITION

Polymer liquid crystal (PLC) macromolecules consisting of LC and flexi ble sequences are considered, particulary at the phase transition LC-i from an anisotropic to the isotropic phase. The Flory lattice model i s used for formulation of the partition function; the orientation dist ribution function for LC interactions introduced by Flory and Ronca is included. While Flory and collaborators have improved the original Fl ory theory by taking into account the Maier and Saupe molecular mean f ield theory of liquid crystallinity, we now use the Landau approach fo r calculating the Helmholtz function of the system as a function of th e orientation parameter s. This leads to formulas for parameters of th e model in the vicinity of the LC-i transition. The critical values at the transition of the strength of orienting interactions s, the syste m temperature, and the anisotropy of LC sequences are calculated and d iscussed. The treatment is limited to monodisperse systems.