Highly tilted liquid crystalline materials possessing a direct phase transition from antiferroelectric to isotropic phase

2016 ◽  
Vol 171 ◽  
pp. 33-38 ◽  
Author(s):  
K. Milewska ◽  
W. Drzewiński ◽  
M. Czerwiński ◽  
R. Dąbrowski ◽  
W. Piecek
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Isotropic Phase ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials

The Dynamic Properites of Confined Antiferroelectric Liquid Crystal Investigated By Photon Correlation Spectroscopy

1999 ◽  
Vol 559 ◽  
Author(s):  
Yu.P. Panarin ◽  
C. Rosenblatr ◽  
F.M. Aliev
Keyword(s):  
Phase Transition ◽  
Porous Media ◽  
Liquid Crystalline ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
Crystalline Materials ◽  
Liquid Crystalline Phases ◽  
Liquid Crystalline Materials ◽  
Structural Aspects

ABSTRACTDynamic light scattering was used to examine ferrielectric liquid crystalline phases in porous media. Whereas in larger pores (200 Å) ferrielectric phases were observed, they were not found in the smallest pores (200 Å). Additionally, the temperatures of SmC - SmA phase transition were found to be suppressed in the pores relative to bulk, while SmCA - SmCγ phase transition is not affected by the confinement. These observations have been explained by the structural aspects of antiferroelectric liquid crystalline materials in a confined geometry and show the importance of long range electrostatic interaction for existence of ferrielectric phases.

Universal Scaling of Alpha Relaxation in Complex Liquids

2001 ◽  
Vol 56 (12) ◽  
pp. 893-894 ◽  
Author(s):  
A. Kurbatov ◽  
A. Drozd-Rzoska ◽  
S. J. Rzoska ◽  
M. Paluch ◽  
P. Malik ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
Liquid Crystalline ◽  
Isotropic Phase ◽  
Scaling Analysis ◽  
Crystalline Materials ◽  
Universal Scaling ◽  
Molecular Glass ◽  
Complex Liquids ◽  
Liquid Crystalline Materials

Abstract A plot is given, showing the result of a scaling analysis of dielectric loss curves containing, apart from low molecular glass former data (glycerol, dibutyl phtalate), also loss curves of the following liquid crystalline materials, mostly in the iso­ tropic phase: 4-(2-methylbutyl)-4'cyanobiphenyl (5*CB, supercooled isotropic phase), 4-cyano-4-n-alkyl biphenyls (nematogens 5CB and 8CB, isotropic phase), 4-(4-cyano-4-butylcyclohexyl)-4'-octylbiphenyl (laterally substituted nema-togen, isotropic phase), and 4-n-alkyl-4'-isothiocyanatobiphe-nyl (5 and 10 BT, isotropic and SmE phases). The plot applies the scaling formula originally proposed for glassforming, super­ cooled liquids [Dendzik et al.7]. The result supports the recent suggestion that dielectric relaxation in the isotropic phase of nematogens may show some features typical for "glassy" mate­ rials.

scholarly journals Laser triggered phase transition in photothermal liquid crystals

2017 ◽  
Vol 53 (47) ◽  
pp. 6339-6342 ◽  
Author(s):  
Mathieu Ciancone ◽  
Franck Camerel
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
High Temperature Phase ◽  
Pure Liquid ◽  
Temperature Phase ◽  
Spatial Control ◽  
Crystalline Materials ◽  
Temperature Phase Transition ◽  
Liquid Crystalline Materials

Laser irradiation allows rapid high temperature phase transition directly from room temperature in pure liquid crystalline materials built around photothermal cores with a high spatial control and responsivness.

scholarly journals PHASE TRANSITION STUDIES OF CHOLESTERYL PALMITATE, CHOLESTERYL DECANOATE AND THEIR MIXTURES USING DIELECTRIC, EPR AND DTA TECHNIQUES

2021 ◽  
Vol 9 (11) ◽  
pp. 210-223
Author(s):  
Sanjai Misra ◽  
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Order Parameter ◽  
Liquid Crystalline ◽  
Paramagnetic Resonance ◽  
Crystalline Materials ◽  
Phase Transition Temperatures ◽  
Cholesteryl Palmitate ◽  
Liquid Crystalline Materials ◽  
Electron Paramagnetic

The phase transition of two liquid crystalline materials, namely cholesteryl palmitate and cholesteryl decanoate and their mixtures (by weight)are studied using dielectric, Electron paramagnetic resonance (EPR) and differential thermal analysis (DTA) techniques. From the dielectric measurements, the phase transition temperatures were determined from the discontinuities in the curve between dielectric constant and temperatures for all the samples investigated. Further, since mixing of two liquid crystals modifies the transition of phases, the measurements were carried out on the mixtures of the two liquid crystals. Order parameter for each sample was calculated at varying temperatures by measuring the hyperfine splitting of three line EPR spectrums. The discontinuities in the curve between order parameter and the temperature again indicated the phase transition of the liquid crystals and their mixtures. A DTA study on these samples was also carried out in order to probe further their transitional behaviour. The DTA records of both the liquid crystals and their mixtures support the transition behaviour observed from the dielectric and EPR measurements.

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