A cholesteric liquid crystal (CLC) – cholesteryl tridecylate (X-20) was doped with nanoparticles of shungite carbon (Sh) to effectively improve some physicochemical properties of the CLC matrix for the further use in electronic devices. The influence of Sh (concentration of 0.005 and 0.02 wt. %) on phase transition temperatures of X-20 was studied. Addition of 0.005 wt. % of Sh shifts phase transition temperatures upward, while the concentration increase to 0.02 wt. % leads to the opposite effect. These data were taken into account during the study of dielectric properties in different phase states. The dielectric properties were studied in the frequency range from 20 Hz to 10 MHz. Only for the system X-20/Sh (0.02 wt. %), dispersion of the dielectric permittivity was observed. The dispersion was caused by the appearance of additional relaxation processes and it was substantially more extended than the classical Debye theory suggests. The results of the research show that the ‘CLC – Sh nanoparticles’ composites can be used as promising materials to increase the efficiency of radio electronics devices.
The influence of molecular structure peculiarities on the supramolecular organization in the bulk and thin layers was studied by the example of two new meso-substituted ligands of tetraphenylporphyrin with substitution in alkoxygroups (-OC4H9) in para- or ortho-positions of phenyl rings. It is established that meso-alkyloxysubstituted tetraphenylporphyrin with substituents (-OC4H9) in the ortho-position (compound I) shows thermotropic monotropic mesomorphism, whereas the substitution in para-position (compound II) leads to the mesophase disappearance. The influence of substituent position on supramolecular organization of meso-substituted porphyrins in thin films was shown.
24 September 2018 in Liquid Crystals and their Application