Synthesis and Mesomorphism of a Novel Triphenylene-Based Discotic Liquid Crystal with Chiral Chain

2012 ◽  
Vol 557-559 ◽  
pp. 1062-1065 ◽  
Author(s):  
Ming Xia Zhang ◽  
Yi Fei Wang ◽  
Chun Xiu Zhang ◽  
Hao Wu ◽  
Jia Ling Pu
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Ir Spectra ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Phase Transition Behavior ◽  
Chemical Structures ◽  
Discotic Liquid Crystal ◽  
Ft Ir ◽  
Crystal Compound

A novel triphenylene-based discotic liquid crystal compound was synthesized in this study. The chemical structures of compounds were characterized by 1HNMR spectra, FT-IR spectra and were confirmed. The phase transition behavior was studied in the combination of texture observation by DSC and POM equipped with a temperature-controllable hot-stage. The object compound showed liquid crystal phase and the results showed that columnar liquid crystal phase between 90.1°C and 138.1 °C during heating.

Evidence for a liquid crystal phase transition in two-dimensional electrons in high Landau levels

2002 ◽  
Vol 12 (9) ◽  
pp. 377-380
Author(s):  
K. B. Cooper ◽  
M. P. Lilly ◽  
J. P. Eisenstein ◽  
L. N. Pfeiffer ◽  
K. W. West
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Landau Levels ◽  
Crystal Phase ◽  
Two Dimensional ◽  
Liquid Crystal Phase ◽  
Stripe Phase ◽  
Stripe Order ◽  
Crystal Phase Transition ◽  
Liquid Crystal Phase Transition

Transport measurements of high-mohility two-dimensional electron systems at low temperatures have revealed a large resistance anisotropy around half-filling of excited Landau levels. These results have been attributed to electronic stripe-phase formation with spontaneously broken orientational symmetry. Mechanisms which are known to break the orientational symmetry include poorly-understood crystal structure effects and an in-plane magnetic field, $B_{||}$. Here we report that a large $B_{||}$ also causes the transport anisotropy to persist up to much higher temperatures. In this regime, we find that the anisotropic resistance scales sublinearly with $B_{||}/T$. These observations support the proposal that the transition from anisotropic to isotropic transport reflects a liquid crystal phase transition where local stripe order persists even in the isotropic regime.

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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