scholarly journals Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement

2019 ◽  
Vol 1 (3) ◽  
pp. 1104-1116 ◽  
Author(s):  
Arda Yildirim ◽  
Kathrin Sentker ◽  
Glen Jacob Smales ◽  
Brian Richard Pauw ◽  
Patrick Huber ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Phase Behavior ◽  
Dielectric Spectroscopy ◽  
Orientational Order ◽  
Scanning Calorimetry ◽  
Discotic Liquid Crystal ◽  
Molecular Ordering

The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLCs under cylindrical nanoconfinement, for nanopore diameters ranging from 161 nm down to 12 nm, are studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS).

Hexabenzocoronenes Bearing Odd Carbon Alkyl Chains as Columnar Discotic Liquid Crystal

2011 ◽  
Vol 181-182 ◽  
pp. 189-192
Author(s):  
Xu Ying Liu ◽  
Yu Jiang ◽  
Rui Cheng ◽  
Wen Guang Wang ◽  
Jia Ling Pu
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Phase Behavior ◽  
Scanning Calorimetry ◽  
Alkyl Chains ◽  
Discotic Liquid Crystal ◽  
Phase Transition Temperatures ◽  
The Difference ◽  
Rigid Plane

Two HBC derivatives (HBC-C13and HBC-C15), both containing 6 odd-carbon alkyl chains surrounding the rigid plane core, were investigated as discotic liquid crystal. The difference between their thermal behaviors has been investigated by using differential scanning calorimetry (DSC). Their mesomorphic phase behavior was observed by polarizing optical microscopy (POM). A remarkable odd-even effect in the phase transition temperatures was observed for all HBC derivatives (HBC-C12, HBC-C13, HBC-C14, HBC-C15and HBC-C16).

Mesophase Studies and Charge Transportation Properties of 3,6-dicarbethoxy-2,7,10,11-tetra-pentyloxytriphenylene

2011 ◽  
Vol 181-182 ◽  
pp. 193-196
Author(s):  
Chun Xiu Zhang ◽  
Jia Ling Pu ◽  
Hao Wu ◽  
Ao Zhang ◽  
Ming Xia Zhang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Chemical Structure ◽  
Room Temperature ◽  
Time Of Flight ◽  
Scanning Calorimetry ◽  
Columnar Phase ◽  
Discotic Liquid Crystal ◽  
Time Of Flight Method

In this study, a triphenylene-based discotic liquid crystal 3,6-dicarbethoxy-2,7,10,11-tetra-pentyloxytriphenylene was synthesized. The chemical structure was characterized by FTIR, 1HNMR.The mesophases of the material synthesized here was characterized by using polarizing optical microscopy (POM), differential scanning calorimetry (DSC). It was found that the compound displayed columnar phase during cooling at 164.7 °C and the columnar phase can be preserved even at room temperature. The charge transportation properties of the compound were measured by using time-of-flight method.

Mesomorphism of Hexa-Peri-Hexabenzocoronene Discotic Liquid Crystals with Odd-Carbon Alkyl Chains

2012 ◽  
Vol 554-556 ◽  
pp. 43-46 ◽  
Author(s):  
Rui Cheng ◽  
Wen Guang Wang ◽  
Teng Zhou Yang ◽  
Yu Jiang ◽  
Jia Ling Pu
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Liquid Crystal ◽  
Discotic Liquid Crystals ◽  
Scanning Calorimetry ◽  
Alkyl Chains ◽  
Discotic Liquid Crystal ◽  
Phase Transition Temperatures ◽  
The Relationship

A new HBC derivative HBC-C17containing 6 odd-carbon alkyl chains surrounding the hexabenzocoronene core was synthesized, and investigated as discotic liquid crystal along with HBC-C13and HBC-C15. The thermal behaviors have been investigated by using differential scanning calorimetry (DSC). And mesomorphic phase behavior of HBC-C17was observed by polarizing optical microscopy (POM). A remarkable variation in the phase transition temperatures was observed for these three HBC derivatives (HBC-C13, HBC-C15and HBC-C17). Moreover, the mesomorphism of these HBC derivatives can be compared with HBC-C12, HBC-C14and other HBCs with even carbon alkyl chains, meanwhile the relationship between the length of substitutes and thermal properties of HBCs is also studied.

Synthesis and Phase Behavior of a New Thiophene Monomer as Nematic Liquid Crystal

2014 ◽  
Vol 989-994 ◽  
pp. 185-188
Author(s):  
Lin Wang ◽  
Yu Jiao Xie ◽  
Xing Xing Zhang ◽  
Jian She Hu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Phase Behavior ◽  
Optical Microscopy ◽  
Nematic Liquid Crystal ◽  
Chemical Structure ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Heating And Cooling ◽  
Ft Ir

The synthesis of a new liquid crystal thiophene monomer of (E)-4-(6-(3-(thiophen-3-yl)- acryloyloxy) hexyloxy) biphenyl-4’-ethylbenzoate (LC-M) is presented. The chemical structure of this monomer and intermediate compounds was characterized by FT-IR and1H-NMR. The phase behavior was investigated by polarizing optical microscopy and differential scanning calorimetry. LC-M showed nematic threaded and schlieren textures on heating and cooling cycles.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

Molecular Dynamics and Kinetics of Isothermal Cold Crystallization in the Chiral Smectogenic 3F7HPhH6 Glassformer

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1487
Author(s):  
Aleksandra Deptuch ◽  
Małgorzata Jasiurkowska-Delaporte ◽  
Ewa Juszyńska-Gałązka ◽  
Anna Drzewicz ◽  
Wojciech Zając ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Cold Crystallization ◽  
Scanning Calorimetry ◽  
Broadband Dielectric Spectroscopy ◽  
Smectic C ◽  
Dimension Analysis ◽  
Fractal Dimension Analysis ◽  
Kinetics Of

An investigation of the glass transition of the antiferroelectric smectic C*A phase and cold crystallization of (S)-4’-(1-methylheptylcarbonyl)biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluoro- butoxy)heptyl-1-oxy]benzoate (denoted as 3F7HPhH6) by differential scanning calorimetry, polarizing optical microscopy and broadband dielectric spectroscopy is presented. The fragility index mf = 72, classifying 3F7HPhH6 as a glassformer with intermediate fragility, was obtained from the temperature dependence of the α-process relaxation time, measured upon cooling. Duplication of the α-process was observed exclusively upon heating, before the onset of cold crystallization, and is connected with the pre-transitional effect. The presence of two crystal phases likely influences the kinetics of cold crystallization; the idea stems from a comparison with previous results for the 3F7HPhF6 and 3F7HPhH7 compounds. Additionally, the presence of the smectic C*α; sub-phase in a narrow temperature range was proved based on the differential scanning calorimetry and broadband dielectric spectroscopy results, as well as the fractal dimension analysis of the textures obtained by polarizing optical microscopy.

scholarly journals Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene)hydrazines

2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Luminescent Properties ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Step Procedure ◽  
Liquid Crystalline Materials

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.

Dependence of Phase Transition of a Bent-Core Liquid Crystal on the Heating Rate

2010 ◽  
Vol 663-665 ◽  
pp. 787-790 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Heating Rate ◽  
Broad Peak ◽  
Crystal Phase ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Crystal Compound

A bent-core liquid crystal compound N,N-bis (4-propoxybenzylidene)benzene- 1,3-diamine was synthesized. Phase transition properties of the synthesized compound with the deferent heating rate were characterized with differential scanning calorimetry and polarized optical microscopy. , respectively. Our results demonstrated that the bent-core compound exhibited the completely undivided multi-phases in heating-rate ranges from 1oC/min to 6oC/min while it showed a broad-peak crystal phase in higher heating-rate ranges of 7-10oC/min for the first heating.

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