Miscibility in cross-linked polymer-solvent systems with nematic interactions

Model phase diagrams of cross-linked polymers and low molecular weight solvent systems with nematic interactions are discussed. A combination of classical theories of network elasticity due to cross-links, isotropic mixing with solvent, and a nematic interaction of the Maier-Saupe type yields a variety of phase behaviors. The network elasticity parameters and the Flory-Huggins interaction parameter are assumed to be function of the volume fraction in contrast to our previous studies of analogous systems. Effects of nematic order on the miscibility of cross-linked polymers and low molecular weight LC are discussed by comparison with the corresponding isotropic systems. The case of side chain liquid crystal cross-linked networks and isotropic solvents is also examined within the same theoretical scheme. The influence of cross-linking density and the reference polymer volume fraction at cross-linking on the phase behavior is also invoked.