A statistical-mechanical model of polymer liquid crystals subjected to external deformations.

We consider the nematiclike system of polymer liquid crystal (PLC) macromolecules represented by the Flory semiflexible chain model. Segments of the flexible (F) spacers are shorter than the LC hard-rod sequences. We investigate effects of imposition of external deformations. The behavior of LC sequences is largely governed by orienting interactions while for F spacers the short-range interactions determined by the chemical structure are the most important. The stress-strain relation is obtained in addition to the orientation-deformation relations. Orientational order phase transitions caused by the external deformations of the system are recognized and described.