Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals

2015 ◽  
Author(s):  
T. N. Govindaiah ◽  
H. R. Sreepad ◽  
K. N. Sridhar ◽  
G. R. Sridhara ◽  
N. Nagaraja
Keyword(s):  
Liquid Crystals ◽  
Binary Mixture ◽  
Nematic Phase ◽  
Liquid Crystalline

scholarly journals Order Parameters, Orientational Distribution Functions and Heliconical Tilt Angles of Oligomeric Liquid Crystals

2019 ◽  
Author(s):  
Richard Mandle ◽  
John W. Goodby
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
Order Parameter ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Thermal Evolution ◽  
Order Parameters ◽  
Distribution Functions ◽  
Orientational Distribution

We compare the order parameters, orientational distribution functions (ODF) and heliconical tilt angles of the TB phase exhibited by a liquid-crystalline dimer (CB7CB) to a tetramer (O47) and hexamer (O67) by SAXS/WAXS. Following the N-TB phase transition we find that all order parameters decrease, and while 〈P2 〉 remains positive 〈P4 〉 becomes negative. For all three materials the order parameter 〈P6 〉 is near zero in both phases. The ODF is sugarloaf-like in the nematic phase and volcano-like in the TB phase, allowing us to estimate the heliconical tilt angle of each material and its thermal evolution. The heliconical tilt angle appears to be largely independent of the material studied despite the differing number of mesogenic units.

Lyotropic nematic phase exhibited in binary mixture of two liquid crystals

2015 ◽  
Author(s):  
T. N. Govindaiah ◽  
H. R. Sreepad ◽  
G. R. Sridhara ◽  
K. N. Sridhar ◽  
N. Nagaraja
Keyword(s):  
Liquid Crystals ◽  
Binary Mixture ◽  
Nematic Phase

EFFECT OF THICKNESS OF LIQUID CRYSTALLINE LAYER ON THE THERMOTROPIC AND THERMODYNAMICAL PROPERTIES OF NEMATIC-ISOTROPIC LIQUID AND ISTROPIC LIQUID-NEMATIC PHASE TRANSITIONS

2006 ◽  
Vol 20 (23) ◽  
pp. 3383-3394 ◽  
Author(s):  
ÖMER POLAT ◽  
ARIF NESRULLAJEV ◽  
ŞENER OKTIK
Keyword(s):  
Phase Transitions ◽  
Liquid Crystals ◽  
Interaction Energy ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Isotropic Liquid ◽  
Crystalline Layer ◽  
Thermodynamical Properties ◽  
Work Effect

In this work, effect of thickness of the liquid crystalline layer on the morphologic, thermotropic and thermodynamical properties of the nematic–isotropic liquid and isotropic liquid–nematic phase transitions in Shiff based liquid crystals has been investigated. The shift of temperatures of the nematic–isotropic liquid and isotropic liquid–nematic phase transitions to the lower temperatures and the widening of linear and temperature widths of the heterophase regions of these phase transitions by the increase in the thickness of liquid crystalline layer have been found. The effect of thickness of liquid crystalline layer on morphologic, thermotropic and thermodynamical properties of liquid crystals under investigations is connected with change of interaction energy between liquid crystalline molecules and reference surfaces.

scholarly journals Synthesis, Characterization and Study of Mesomorphic Behavior of New Bent and Liner Core Compounds Containing Heterocyclic

2017 ◽  
Vol 30 (3) ◽  
pp. 195
Author(s):  
Nisreen H. Karam ◽  
Alaa K. Shanshal
Keyword(s):  
Liquid Crystals ◽  
Schiff Bases ◽  
Aromatic Amines ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Thioglycolic Acid ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Phosphorous Oxychloride ◽  
Compound Xvii

  We described herein the synthesized and characterized of new bent and liner core compounds containing thiazolidin-4-one ring[XI-XIII] and [XIV-XVI] respectively. These compounds synthesized by sequence reactions starting from reaction resorcinol or hydroquinone with chloracetyl chloride to yield compounds [I] and [II] ,then the later compounds reactant with 4-hydroxybenzylaldehyde to product dialdehyde compounds [III] and [IV] .The Schiff bases compounds[V-VII] and [VIII-X] synthesized from reaction the compound [III] or [IV] with different aromatic  amines, while the bent and liner core mesogens containing thiazolidin-4-one ring [XI-XIII] and [XIV-XVI] synthesized from reaction Schiff bases compounds[V-VII] or  [VIII-X] with thioglycolic acid. In addition estrfecation of cinnamic acid with methanol to yield ester compound[XVII]which was converted to their acid hydrazid[XVIII] and the acid hydrazid reacted with glysine in phosphorous oxychloride to yield (5-styryl-1,3,4-oxadiazol-2-yl) methanamine [XIX]. Then reactant the1,3,4-oxadiazol compound[XIX]    with dialdehyde compound [III] or  [IV] to product new Schiff bases compounds [XX] and [XXI]  , afterword added thioglycolic acid to give new thiazolidin-4-one derivatives [XXII] and [XXIII], respectively.        The synthesized compounds were characterized by melting points , FTIR ,1HNMR and mass spectroscopy (of some of them).The liquid crystalline properties were studied by hot stage polarized optical microscopy (POM) and differential scanning calorimetry(DSC).All the  Schiff bases compounds [V-X] showed liquid crystals phases while thiazolidin-4-one derivatives[XI-XIII],[XIV-XVI]and [XXIII] didn’t show any liquid crystals properties except the compound [XXII] showed enantiotropic nematic phase.

Formation of Lyotropic Micellar Nematic Phase in Binary Mixture of Liquid Crystals

2015 ◽  
Vol 608 (1) ◽  
pp. 166-173 ◽  
Author(s):  
T. N. Govindaiah ◽  
H. R. Sreepad ◽  
Nagappa
Keyword(s):  
Liquid Crystals ◽  
Binary Mixture ◽  
Nematic Phase

scholarly journals Order Parameters, Orientational Distribution Functions and Heliconical Tilt Angles of Oligomeric Liquid Crystals

2019 ◽  
Author(s):  
Richard Mandle ◽  
John W. Goodby
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Tilt Angle ◽  
Order Parameter ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Thermal Evolution ◽  
Order Parameters ◽  
Distribution Functions ◽  
Orientational Distribution

We compare the order parameters, orientational distribution functions (ODF) and heliconical tilt angles of the TB phase exhibited by a liquid-crystalline dimer (CB7CB) to a tetramer (O47) and hexamer (O67) by SAXS/WAXS. Following the N-TB phase transition we find that all order parameters decrease, and while 〈P2 〉 remains positive 〈P4 〉 becomes negative. For all three materials the order parameter 〈P6 〉 is near zero in both phases. The ODF is sugarloaf-like in the nematic phase and volcano-like in the TB phase, allowing us to estimate the heliconical tilt angle of each material and its thermal evolution. The heliconical tilt angle appears to be largely independent of the material studied despite the differing number of mesogenic units.

scholarly journals A 1,6-Diphenylpyrene-Based, Photoluminescent Cyclophane Showing a Nematic Liquid-Crystalline Phase at Room Temperature

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 92 ◽  
Author(s):  
Yoshimitsu Sagara ◽  
Tatsuya Muramatsu ◽  
Nobuyuki Tamaoki
Keyword(s):  
Liquid Crystals ◽  
Crystalline Phase ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Liquid Crystalline Phase ◽  
Condensed State ◽  
Liquid Crystalline Phases ◽  
Potential Applications ◽  
Blue Photoluminescence

Photoluminescent nematic liquid crystals have been an attractive research target for decades, because of their potential applications in optoelectrical devices. Integration of luminescent motifs into cyclic structures is a promising approach to induce low-ordered liquid-crystalline phases, even though relatively large and rigid luminophores are used as emitters. Here, we demonstrate a 1,6-diphenylpyrene-based, unsymmetric cyclophane showing a stable nematic phase at room temperature and exhibiting strong photoluminescence from the condensed state. The observed sky-blue photoluminescence was dominated by the emission species ascribed to assembled luminophores rather than monomers.

High Pressure Studies of Liquid Crystalline Transitions

1983 ◽  
Vol 22 ◽  
Author(s):  
R. Shashidhar
Keyword(s):  
High Pressure ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Maximum Pressure ◽  
Multicritical Point ◽  
Smectic A ◽  
High Pressure Studies ◽  
Molecular Ordering

ABSTRACTSome of the important results emerging from our recent investigations on liquid crystals at high pressure are presented. In particular the following topics will be discussed: i) The relation between Pm, the maximum pressure of smectic stability, and the temperature range of the nematic phase in reentrant nematogenic compounds. ii) Piezothermal studies in the vicinity of the smectic A-nematic transition in 8 OCB. iii) The effect of molecular ordering on the pressure behaviour of the nematic-isotropic transition in reentrant nematic mixtures. iv) The first observation of a multicritical point in a single component liquid crystal.

Liquid-crystalline behaviour and electrorheological effect of phthalocyanine-based ionic liquid crystals

2020 ◽  
pp. 1-10
Author(s):  
Aikebaier Reheman ◽  
Shuangying Hu ◽  
Lianjun Cao ◽  
Danhua Xie ◽  
Guiyang Yan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Electrorheological Effect ◽  
Ionic Liquid Crystals

Substrate induced freezing, melting and depinning transitions in two-dimensional liquid crystalline systems

2022 ◽  
Author(s):  
Bharti bharti ◽  
Debabrata Deb
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystals ◽  
Molecular Dynamics Simulations ◽  
Liquid Crystalline ◽  
Two Dimensional ◽  
One Dimensional ◽  
The One ◽  
Dynamics Simulations

We use molecular dynamics simulations to investigate the ordering phenomena in two-dimensional (2D) liquid crystals over the one-dimensional periodic substrate (1DPS). We have used Gay-Berne (GB) potential to model the...

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