Shevchuk О. The influence of fullerenes and dyes on dielectric and photodielectric properties of ferroelectric liquid crystals.

The experimental research results of dyes and fullerenes admixtures (С60 with covalently sewed molecules of octanediamine and mixture (С60 + С70)) influence on dielectric and photodielectric properties of ferroelectric liquid crystals (FLC) are presented. Also, the research results of the influence of light on dielectric parameters of С60 - FLC and С60 - isotropic liquid film structures are given here. It is experimentally shown that the parameters of high-frequency dielectric relaxation process (peculiar to smectic phases of FLC) do not depend on the introduction of dyes and (С60 + С70) mixture. Low-frequency dielectric relaxation process is observed in all phases of planar oriented sample. The imbedding of dyes and fullerenes admixtures leads to the change of its parameters. It is obtained that the analysis of temperature conductivity dependence at alternating current makes it possible to investigate the influence of admixtures of different types on ferroelectric properties of liquid crystals. It is shown, that on the basis of mixing the fullerenes and FLC it is possible to create photosensitive composites. In contradiction to other phases, in SmC* phase irradiation of the composite leads to displacement current increase (positive photodielectric effect). A possible mechanism of this phenomenon is suggested. It is experimentally shown that dielectric parameters of two-layer structures С60 - FLC vary under the influence of light. Thus, in contrast to other phases, the illumination in SmC* phase leads to the decrease of capacity (negative photodielectric effect). The explanation of this effect is suggested.