Chernyshuk S. Behavior of micro and macroparticles in nematic liquid crystals.

Thesis is devoted to the theoretical investigation of the microparticles (nanometer size) and macroparticles (micrometer size) in the nematic liquid crystal. General concentrational dependence of the elastic constants and inverse pitch in nematic-cholesteric and cholesteric-cholesteric mixtures are found which are in agreement with experiment data. Spinodal decomposition in such mixture can lead to the appearance of the second period in the director field. Theory of elastic interaction between arbitrary macroparticles in nematic liquid crystal was developed . For the first time the Coulomb-like attraction between two particles was found when equal nonzero torque moment is applied to them by the nematic. It was shown that interference of deformations from many particles leads to the exponential screening of interaction potential with screening length greater than average distance between particles. As well general formulas are obtained for the energy of the arbitrary particle in the curved director field. It is shown, that quadrupole particles with planar anchoring are attracted towards the regions with high splay deformations. The results are used for the explanation of the "cellular" texture in the ferronematics in the presence of the magnetic field.