Arif Nesrullajev

Refracting and birefringent properties of lyotropic nematic mesophases

Abstract In this work, we investigated refracting, birefringent and thermotropic properties of lyotropic nematic mesophases. In particular, the morphological properties of nematic–calamitic and nematic–discotic lyotropic mesophases have been investigated in the heterophase regions at lyotropic nematic–isotropic liquid phase transitions. The changes in isotropic, mean refractive index, and anisotropic, birefringence, optical properties of the nematic mesophases by the changes in temperature have been observed to have fluctuational character in the heterophase regions of lyotropic nematic–isotropic liquid phase transitions. This character reflects the character of changes in shapes and sizes of micelles and in symmetries of the mesophases in the heterophase region.

N-salicylidene anilines and their copper complexes: comparative investigations of mesomorphic, morphologic, thermotropic and thermodynamical properties

In this work comparative studies of the mesomorphic and morphologic properties and thermal behaviour of new Schiff base N-salicylidene aniline ligands and the effects of Cu(II) additions on these properties have been carried out. Peculiarities of phase transformations between smectic and nematic mesophases, smectic mesophase and isotropic liquid and nematic mesophase and isotropic liquid during both heating and cooling of N-salicylidene aniline ligands and their Cu(II) complexes have been investigated. The studies have been carried out using polythermic polarizing microscopy, DSC analysis and a capillary temperature wedge.

Hexagonal lyotropic liquid crystalline mesophase: change of rod-like micelle sizes with changes in concentrations

In the present work, change of rod-like micelle sizes with change of amphiphile concentration in hexagonal mesophase and the effect of inorganic salt additions on the effective length of these micelles have been studied. The investigations were made by the using of electrical conductivity method in shear flow. The dependence of form factor on the anisometricity parameter of rod-like micelles were determined for investigated lyotropic systems.

INDUCED CHANGES OF THERMOTROPIC PROPERTIES OF PHASE TRANSITIONS BETWEEN SMECTIC A MESOPHASE AND ISOTROPIC LIQUID: EFFECT OF SURFACES

In this work, the effect of thin films on the thermotropic and thermo-optical properties and peculiarities of the phase transitions between the smectic A and isotropic liquid have been investigated. Peculiarities of the heterophase regions of the straight smectic A-isotropic liquid and reverse isotropic liquid-smectic A phase transitions have been studied. Change of morphologic properties of the heterophase regions, shift of the phase transition temperatures and the change of temperature widths of these heterophase regions under thin film influence have been observed.

Nonlinear thermotropic and thermo-optical behaviour of planar oriented textures in nematic liquid crystals at phase transitions

Thermotropic, thermo-morphologic and thermo-optical properties of the planar oriented nematic liquid crystals have been investigated for large temperature interval and especially for the direct nematic - isotropic liquid and the reverse isotropic liquid - nematic phase transition regions. Temperature dependences of the optical transmission, absorption coefficient and optical birefringence for both heating and cooling processes were obtained. Nonlinear thermotropic and thermo-optical behaviour and temperature hysteresis for the optical transmission, absorption coefficient and optical birefringence at the phase transitions has been found.

Changes of thermo-morphologic and thermotropic properties of liquid crystals at direct and reverse nematic mesophase ↔ isotropic liquid phase transitions: surface-induced effect

In this work, the effect of thin films on the thermo-morphologic and thermotropic properties of the phase transitions between the nematic mesophase and isotropic liquid has been investigated. Investigations have been carried out for both the heating and cooling processes. The temperature and linear widths of the biphasic regions of the direct and reverse phase transitions in nematic liquid crystals versus thickness of the thin films have been calculated with a high accuracy. The shift of the nematic mesophase–isotropic liquid and the isotropic liquid–nematic mesophase phase transition temperatures to higher temperatures and the enlargement of the temperature and linear widths of the biphasic regions as the effect of surfaces have been found.

EFFECT OF THE SURFACES ON ORIENTATIONAL PROPERTIES AND PECULIARITIES OF PHASE TRANSITIONS IN THERMOTROPIC NEMATICS

In this work, the effect of thin films on the orientational, thermotropic and optical properties and on the peculiarities of the nematic–isotropic liquid phase transition has been carried out. The planar textures of MBBA+EBBA eutectic mixture on the surfaces coated with Al2O3 and ZrO2 thin films have been obtained. The optical and thermodynamical parameters of the obtained, oriented textures have been determined. The effect of thin films on the temperature width of heterophase region and on the nematic–isotropic liquid phase transition temperatures has been investigated. The shift of the phase transition temperatures and the change of the temperature width of the heterophase region have been revealed. For the analysis of peculiarities of the nematic–isotropic liquid phase transition and the heterophase regions of this transition, the mean field theory has been used.

Sizes and Anisometricity of Micelles in Lyotropic Liquid Crystalline Mesophases: Sodium Lauryl Sulphate/Water/Decanol Lyotropic System

Abstract Structural peculiarities of the rod-like micelles in lyotropic liquid crystalline nematic-calamitic and hexagonal mesophases have been investigated. The lengths, the parameters of anisometricity, the form factors and the volumes of these micelles have been determined. The method of the electrical conductivity anisotropy in the orientational shear flow has been used. The rod-like micelles of nematic-calamitic and hexagonal mesophases were considered as the prolonged ellipsoids.

4-(OCTYLOXY)-N-(4-HEXYLPHENYL)-2-HYDROXYBENZALIMINE THERMOTROPIC COMPOUND: MORPHOLOGIC, MESOMORPHIC, THERMOTROPIC, THERMOOPTICAL AND THERMODYNAMICAL PROPERTIES

In this work, the mesomorphic, morphologic, thermotropic, thermooptical, and thermodynamical properties of 4-(octyloxy)-N-(4-hexylphenyl)-2-hydroxybenzalimine thermotropic liquid crystalline compound, which was synthesized by our group, have been studied in detail. This compound displays smectic C and nematic mesophases. These mesophases are enantiotropic and exhibit specific confocal and schlieren textures, respectively. Thermotropic, thermooptical, and thermodynamical properties of the compound at direct and reverse phase transitions between smectic C and nematic mesophases and also between nematic mesophase and isotropic liquid have been investigated. The peculiarities of the bistable heterophase regions of these phase transitions have been studied.

Surface-induced and oriented textures of smectic liquid crystals: effect of thin films

In this work, the effect of YBa2Cu3O7−x complex compound thin films on the morphological, thermotropical, optical and orientational properties of smectic liquid crystals have been studied. The peculiarities of surface-induced textures and dynamics of their temperature transformations have been investigated. Stable, homogeneous and reproducible oriented textures of smectic liquid crystals have been obtained.