Hexabenzocoronene with Swallow-Tailed Substitutes: Synthesis, Characterization and Properties

2011 ◽  
Vol 181-182 ◽  
pp. 147-150 ◽  
Author(s):  
Wen Qing Huang ◽  
Pei Pei Liu ◽  
Bing Bing Wang ◽  
Xu Ying Liu ◽  
Wen Guang Wang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Optical Microscopy ◽  
Thermal Processing ◽  
Self Organization ◽  
Side Chains ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Alkyl Chains

A hexa-peri-hexabenzocoronene (HBC) derivative, substituted at periphery by six swallow-tailed alkyl chains containing ether linkages, has been synthesized. Its thermal properties and self-organization were investigated using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Results showed that the peripheral side chains substituted to the aromatic core could lead the HBC to a dramatically lowered isotropization temperature compared with those reported previously, allowing thermal processing at practical temperatures.

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.

Synthesis and Mesomorphic Properties of a Series of Cholesteric Liquid Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 759-762 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Phase Transition Temperatures ◽  
Second Category ◽  
Mesomorphic Properties

A series of cholesterol liquid crystal compounds was synthesized. Phase-transition temperatures and mesomorphic textures of these synthesized compounds were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. In these molecules the terminal ester chains CnH2n-1COO-, where n was the number of carbon atoms in the terminal ester chains, were linked to the cholesterol core. All of the synthesized cholesterol compounds exhibited mesophases for the first heating. However, as temperature decreased from their clearing points, their micrographs can also be divided into two categories, the first category exhibits branch-like mesophase textures for n in the range of 1-10 while the second category exhibits branch-like crystal textures for n in the range of 11-18.

Influence of Cooling Rates on Phase Transitions of Bent-Core Liquid Crystal 1,3-Phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine]

2010 ◽  
Vol 428-429 ◽  
pp. 247-250 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Cooling Rate ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Polarized Optical Microscopy ◽  
Fast Cooling

The influence of cooling rate on the phase transitions of a three-benzene-ring containing bent-core liquid crystal 1,3-phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine] has been investigated by means of differential scanning calorimetry and polarized optical microscopy. Our results show that the cooling rates in the second cooling run pose significant effects on the phase transitions of the bent-core liquid crystal despite the cooling rates in the first cooling run pose little effects on the phase transitions. In the second cooling run, the banana phases survived only when the cooling rates were in the range of 14~15oC/min whereas both slow cooling rates which were less than 13oC/min and fast cooling rates which were higher than 16oC/min made the banana phases disappeared.

Crystal Morphology and Thermal Properties of PA6/PP-g-MAH/POE Blends

2011 ◽  
Vol 366 ◽  
pp. 314-317
Author(s):  
Ming Tao Run ◽  
Wen Zhou ◽  
Bing Tao Xing ◽  
Meng Yao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Crystal Morphology ◽  
Crystallization Rate ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Acicular Crystal ◽  
Polarized Optical Microscopy ◽  
Twin Screw ◽  
Higher Temperature

The crystal morphology and thermal properties of the PA6/PP-g-MAH/POE blends prepared by twin-screw extruder were studied by polarized optical microscopy (POM) and differential scanning calorimetry (DSC) respectively. The results suggest that the crystal morphology of PA6 is acicular crystal while PP-g-MAH is micro-spherulites; The acicular crystals form across POE phase to PA6 phase, and the acicular crystals of PA6 in the POE phase have better regularity in dimension than those in amorphous PA6 phase. Acting as a compatibilizer, PP-g-MAH improves the miscibility of PA6 and POE, leading to the glass transition temperature of the blends decreases gradually with increasing POE contents. PA6 and PP-g-MAH can crystallize individually, and the formed PA6 crystals induced the crystallization of PP-g-MAH at higher temperature; furthermore, PP-g-MAH and POE components can increase the crystallization rate of PA6.

scholarly journals Kinetics of Non-Isothermal and Isothermal Crystallization in a Liquid Crystal with Highly Ordered Smectic Phase as Reflected by Differential Scanning Calorimetry, Polarized Optical Microscopy and Broadband Dielectric Spectroscopy

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 205 ◽  
Author(s):  
Małgorzata Jasiurkowska-Delaporte ◽  
Tomasz Rozwadowski ◽  
Ewa Juszyńska-Gałązka
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Isothermal Crystallization ◽  
Glassy State ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Kinetics Of

The kinetics of the non-isothermal and isothermal crystallization of the crystalline smectic B phase (soft crystal B, SmBcr) in 4-n-butyloxybenzylidene-4′-n′-octylaniline (BBOA) was studied by a combination of differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and polarized optical microscopy (POM). On cooling, part of the SmBcr phase undergoes conversion to a crystalline phase and the remainder forms a glassy state; after the glass softens, crystallization is completed during subsequent heating. By analyzing the area of the crystal growing in the texture of SmBcr as a function of time, the evolution of degree of crystallinity, D(t), was estimated. It was demonstrated that upon heating, D(t) follows the same Avrami curve as the crystallization during cooling. Non-isothermal crystallization observed during slow cooling rates (3K/min ≤ ϕ ≤ 5K/min) is a thermodynamically-controlled process with the energy barrier Ea ≈ 175 kJ/mol; however, the crystallization occurring during fast cooling (5 K/min > ϕ ≥ 30K/min) is driven by a diffusion mechanism, and is characterized by Ea ≈ 305 kJ/mol. The isothermal crystallization taking place in the temperature range 274 K and 281 K is determined by nucleus formation.

Synthesis, Electrochemical, and Thermal Properties of [3]Ferrocenophane-Containing Chalcone Derivatives

2015 ◽  
Vol 68 (7) ◽  
pp. 1035 ◽  
Author(s):  
Haiying Zhao ◽  
Xueyou Zhu ◽  
Dong Wang ◽  
Shufeng Chen ◽  
Zhanxi Bian
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Transitions ◽  
Optical Microscopy ◽  
Alkyl Chain ◽  
Freezing Process ◽  
Naphthalene Ring ◽  
Scanning Calorimetry ◽  
Chalcone Derivatives ◽  
Heating And Cooling

[3]Ferrocenophane-containing chalcone derivatives with benzene ring (3a–3d) or naphthalene ring (3e–3f) were synthesized and characterized. The potentials for [3]ferrocenophane-containing chalcones cathodically shifted ~70–80 mV compared with those of ferrocene-containing chalcones, indicating easier oxidation by loss of an electron for the former. The thermal behaviours of the prepared compounds were studied by differential scanning calorimetry and polarizing optical microscopy. Compound 3f with terminal alkyl chain of 14 carbon atoms displayed mesophases, whereas other compounds were non-mesomorphic and showed either crystal polymorphic phase transitions or simple melting and freezing process in the heating and cooling cycles.

scholarly journals New cholesteryl containing bent core liquid crystals

2013 ◽  
Vol 78 (5) ◽  
pp. 669-680 ◽  
Author(s):  
Cosmin-Constantin Huzum ◽  
Irina Carlescu ◽  
Gabriela Lisa ◽  
Dan Scutaru
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Benzoic Acids ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Acyl Chlorides ◽  
Esterification Reactions

The paper presents the synthesis and mesomorphic behavior of two new series of bent core liquid crystalline compounds based on a 1,3-dihydroxybezene core and containing a cholesteryl 6-oxyhexanoate wing. The two series were obtained by the esterification of the cholesteryl 6-(3-hydroxyphenoxy)hexanoate core with some 4-((4-(n-alkyloxy)phenyl)azo)benzoic acids (n-alkyl = n-hexyl ? n-dodecyl) or 4-(4-(n-alkyloxy)benzoyloxy)benzoic acids (n-alkyl = n-hexyl ? n-decyl). The esterification reactions were performed via the corresponding acyl chlorides or with the DCC / DMAP system. All the synthesized compounds evidenced enantiotropic liquid crystalline properties, with smectic type textures, when investigated by means of differential scanning calorimetry and polarized optical microscopy. Isotropisation and isotropic to liquid crystal transitions were relatively low (between 89 ? 1460C). The compounds containing the azo-aromatic linking group presented the largest range of stability of the mesophases (between 42 and 870C). All the investigated compounds were thermally stable in the existence range of the mesophases.

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