In this thesis we experimentally study dispersions of ferroelectric microplatelets in nematic liquid crystal. Firstly we introduce basic properties of nematic liquid crystals, nematic colloids and ferroelectrics. Then we describe the materials and methods used for experimental work: polarizing microscopy, atomic force microscope, micromanipulation of particles using optical tweezer and video tracking of colloidal particles. Further on, main results of our experiments are presented. Ferroelectric platelets in nematic liquid crystal planar cell are divided into two categories based on the polarizing microscopy images of the surrounding nematic director configuration: elastic dipoles and elastic quadrupoles. This classification is a basis for investigation of interactions between two platelets in close proximity, when external electric field is set to zero. From experiments in the isotropic phase of the liquid crystal we conclude that the electric dipole moment of the platelets which have not yet been exposed to external electric field is insignificant in the absence of external electric field. Platelets most probably contain many ferroelectric domains. By investigating individual ferroelectric platelets in external electric field we can estimate the direction and size of their electric dipole moment after the reorientation of domains. We also analyze how two adjacent platelets interact in external electric field and conclude that they effectively act as induced electric dipoles, but their electric dipole moment is insignificant in the absence of external electric field. Results of experimental work of the thesis offer new understanding of nematic dispersions of ferroelectric platelets and could contribute to improvements in their application.
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