Lattice model theory of chain stiffening and relaxation properties of macromolecules in the nematic LC state

The relaxation properties of polymer chains In the nematic LC-state or in the external quadrupole field may depend both on the variation of the conformation in the ordered state and on the activation barrier of the molecular (or external) field. This barrier should be surmounted during reorientation of chain elements. The lattice model theory of chain stiffening of macromolecules in the LC-state is proposed. The calculation and comparison of the longitudinal and transversal relaxation spectra for the continuous and discrete rotameric mechanism of the mobility are performed. For the simplest model of a heterogeneous polymer chain the possibility of the more complex relaxational behavior i.e. the existence of two longitudinal and two transversal relaxation spectra was shown.