scholarly journals Liquid crystalline material exhibiting multiple phase transitions: morphologic properties and optical transmission

2017 ◽  
Vol 56 (4) ◽  
pp. 207-216 ◽  
Author(s):  
Arif Nesrullajev
Keyword(s):  
Phase Transitions ◽  
Liquid Crystalline ◽  
Optical Transmission ◽  
Crystalline Material ◽  
Isotropic Liquid ◽  
Smectic A ◽  
Smectic C ◽  
Multiple Phase ◽  
Temperature Dependences ◽  
Liquid Crystalline Material

Morphologic and thermo-optical properties of liquid crystalline material exhibiting multiple phase transitions were investigated in this work. Investigations were carried out for both the direct (by heating) and the reverse (by cooling) phase transitions. Thermo-morphologic properties of the heterophase regions of phase transitions were investigated. Temperature dependences of the optical transmission were studied, the mean optical density of crystalline state, smectic C, smectic A and nematic mesophases was estimated, temperature widths of the heterophase regions ofcrystal↔smectic C,smectic C↔smectic A,smectic A↔nematicandnematic↔isotropic liquidphase transitions were determined with high accuracy.

scholarly journals ‘Quasi-Tricritical’ and Glassy Dielectric Properties of a Nematic Liquid Crystalline Material

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 297 ◽  
Author(s):  
Aleksandra Drozd-Rzoska
Keyword(s):  
Relaxation Time ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Strong Electric Field ◽  
Low Frequency ◽  
Ionic Species ◽  
Crystalline Material ◽  
Isotropic Liquid ◽  
The Impact ◽  
Liquid Crystalline Material

Results of dielectric studies in the nematic and isotropic liquid phases of pentylcyanobiphenyl (5CB), a model rod-like liquid crystalline material, are shown. They are based on the discussion of the evolution of dielectric constant ( ε ), its changes under the strong electric field (nonlinear dielectric effect, NDE), and finally, the primary relaxation time. It is shown that changes in ε T and NDE are entirely dominated by the impact of pretransitional fluctuations (pre-nematic and pre-isotropic, respectively) which are associated with the weakly discontinuous character of the isotropic–nematic phase transition. This influence also extends for the low-frequency, ionic species dominated, region. Notable, that the derivative-based and distortions sensitive analysis revealed the tricritical nature of the I-N transition. Although the glass transition in 5CB occurs in the deeply supercooled state at T g ≈ − 68 ° C , the dynamics (changes of the primary relaxation time) follow a previtreous pattern both in the isotropic and in the nematic phase. Finally, the discussion of the ’molecular’ vs. ‘quasi-critical’ characterizations of the isotropic and nematic phases is presented. It shows the evident prevalence of the ‘quasi-critical-picture’, which offers the consistent temperature parameterization in the total tested temperature range.

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

2008 ◽  
Vol 22 (03) ◽  
pp. 281-291 ◽  
Author(s):  
ARIF NESRULLAJEV ◽  
BELKIZ BILGIN ERAN ◽  
ÇIDEM YÖRÜR
Keyword(s):  
Phase Transitions ◽  
Liquid Crystalline ◽  
Crystalline Compound ◽  
Reverse Phase ◽  
Isotropic Liquid ◽  
Thermodynamical Properties ◽  
Smectic C ◽  
Nematic Mesophase ◽  
Liquid Crystalline Compound

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.

Effect of metallic silver nanoparticles on the alignment and relaxation behaviour of liquid crystalline material in smectic C* phase

2017 ◽  
Vol 122 (11) ◽  
pp. 114102 ◽  
Author(s):  
Tripti Vimal ◽  
Swadesh Kumar Gupta ◽  
Rohit Katiyar ◽  
Atul Srivastava ◽  
Michal Czerwinski ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Liquid Crystalline ◽  
Crystalline Material ◽  
Metallic Silver ◽  
Relaxation Behaviour ◽  
Smectic C ◽  
Liquid Crystalline Material

scholarly journals Hexakis(terthiophenylthio)benzene as a Mew Class Liquid Crystalline Molecule

1999 ◽  
Vol 23 (10) ◽  
pp. 596-597
Author(s):  
Shinobu Inoue ◽  
Shoji Nishiguchi ◽  
Satoshi Murakami ◽  
Yoshio Aso ◽  
Tetsuo Otsubo ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Smectic A ◽  
Smectic C ◽  
Nematic Phases

A disk-like molecule, in which six α-linked terthiophenes are connected to a central benzene core via a thioether linkage, shows a sequence of calamitic liquid crystalline mesomorphism involving smectic C, smectic A and nematic phases.

Phase transitions between smectic A phases as well as smectic C* phases and undulated structures in terminal non-polar compounds

1995 ◽  
Vol 19 (5) ◽  
pp. 629-635 ◽  
Author(s):  
P. Göring ◽  
G. Pelzl ◽  
S. Diele ◽  
P. Delavier ◽  
K. Siemensmeyer ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Polar Compounds ◽  
Smectic A ◽  
Smectic C

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

2006 ◽  
Vol 20 (14) ◽  
pp. 821-833 ◽  
Author(s):  
ARIF NESRULLAJEV ◽  
ŞENER OKTIK
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Phase Transitions ◽  
Isotropic Liquid ◽  
Smectic A ◽  
Phase Transition Temperatures ◽  
Smectic A Phase ◽  
Induced Changes ◽  
Thermotropic Properties

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.

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