The scope and limitations of liquid-crystalline behaviour in monosaccharide amphiphiles Comparison of the thermal behaviour of several homologous series of D-glucose derived compounds with an amino-linked alkyl chain

1990 ◽  
Vol 8 (1) ◽  
pp. 109-121 ◽  
Author(s):  
Henk A. Van Doren ◽  
Ralph Van Der Geest ◽  
Cornelis F. De Ruijter ◽  
Richard M. Kellogg ◽  
Hans Wynberg
Keyword(s):  
Thermal Behaviour ◽  
Homologous Series ◽  
Liquid Crystalline ◽  
Alkyl Chain

4(4-Alkyloxybenzoyloxy)-4' -cyanoazobenzole: Eine homologe Reihe flüssigkristalliner Verbindungen mit der ungewöhnlichen Phasenfolge smektisch A-nematisch-smektisch A / 4(4-Alkyloxybenzoyloxy)-4'-cyanoazobenzenes: A Homologous Series of Liquid Crystals Exhibiting the Unusual Phase Sequence Smectic A -Nematic -Smectic A

1980 ◽  
Vol 35 (11) ◽  
pp. 1384-1388 ◽  
Author(s):  
Gerd Heppke ◽  
Reinhard Hopf ◽  
Bernd Kohne ◽  
Klaus Praefcke
Keyword(s):  
Phase Transition ◽  
Homologous Series ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Phase Region ◽  
Alkyl Chain Length ◽  
Smectic A ◽  
Phase Sequence ◽  
Phase Transition Temperatures

The synthesis and the phase transition temperatures of homologous liquid crystalline 4(4-alkyloxybenzoyloxy)-4'-cyanoazobenzenes with alkyl chain length n = 1-12 and n = 16 are reported. All compounds exhibit smectic A phases; the SA phase region being interrupted by a "re-entrant" nematic phase for alkyl chain lengath n ≥ 9.

Charge mobility in discotic liquid crystalline porphyrins and phthalocyanines measured by PR-TRMC

2003 ◽  
Vol 07 (05) ◽  
pp. 342-350 ◽  
Author(s):  
John M. Warman ◽  
Jessica E. Kroeze ◽  
Pieter G. Schouten ◽  
Anick M. van de Craats
Keyword(s):  
Conjugated Polymers ◽  
Carrier Mobility ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Charge Carrier Mobility ◽  
Chain Structure ◽  
Coupling Element ◽  
Time Resolved ◽  
Liquid Crystalline Phases ◽  
Conductive Properties

The pulse-radiolysis time-resolved microwave conductivity technique, “PR-TRMC”, has been used to determine the charge carrier mobility within columnar stacks of mesomorphic discotic porphyrins and phthalocyanines. The influences of temperature, morphology and variations in the primary molecular structure are demonstrated and discussed. Both the mesomorphic and conductive properties are shown to be dramatically influenced by subtle changes in the peripheral alkyl chain structure or the core-to-chain coupling element. Mobilities close to 1 cm2.V−1.s−1 are found in crystalline solids, and well in excess of 0.1 cm2.V−1.s−1 in columnar, liquid crystalline phases. These values which are even larger than those determined by PR-TRMC for conjugated polymers and similar to values found for electrons and holes in organic single crystals.

scholarly journals Phase Transitions of Side Chain Liquid Crystalline Polymers Having a Terminal Alkyl Chain.

1993 ◽  
Vol 50 (9) ◽  
pp. 687-691 ◽  
Author(s):  
Seiji UJIIE ◽  
Tamami FUKUI ◽  
Kazuko HIGAKI ◽  
Satoshi TAKAHASHI ◽  
Kazuyoshi IIMURA
Keyword(s):  
Phase Transitions ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Crystalline Polymers

scholarly journals Influence of alkyl chain length and fluorine atoms substitution on infrared spectra of chiral liquid crystalline esters

2017 ◽  
Vol 66 (3) ◽  
pp. 63-74
Author(s):  
Anna Drzewicz ◽  
Marzena Tykarska ◽  
Magdalena Żurowska
Keyword(s):  
Molecular Structure ◽  
Infrared Spectroscopy ◽  
Liquid Crystals ◽  
Infrared Spectra ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Rigid Core ◽  
Helicoidal Structure

The infrared spectra were registered for series of three-ring liquid crystalline esters, differing in the structure of alkyl chain, in the substitution of benzene ring by fluorine atoms and in the type of helicoidal structure in the chiral smectic CA phase with antiferroelectric properties. The influence of molecular structure on the shift of signals coming from carbonyl group, located in the rigid core, was observed. Keywords: liquid crystals, helicoidal structure, chiral smectic CA phase, antiferroelectric crystalline phase, infrared spectroscopy

scholarly journals Influence of molecular structure on helicoidal structure and NMR spectra of chiral liquid crystalline esters

2017 ◽  
Vol 66 (2) ◽  
pp. 25-35
Author(s):  
Anna Drzewicz ◽  
Marzena Tykarska ◽  
Mateusz Szala ◽  
Magdalena Żurowska
Keyword(s):  
Molecular Structure ◽  
Nmr Spectra ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Alkyl Chain ◽  
Light Reflection ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Antiferroelectric Phase ◽  
Helicoidal Structure

Three-ring chiral liquid crystalline compounds, forming antiferroelectric phase, differing in the structure of alkyl chain and in the substitution of benzene ring by fluorine atoms were studied. The measurements of helical pitch, based on the selective light reflection phenomenon, were performed as well as 1H and 13C NMR spectra at room temperature were registered. The influence of molecular structure as well as the type of helicoidal structure on the chemical shift of signals coming from chiral center was observed. Keywords: liquid crystals, helicoidal structure, nuclear magnetic resonance, antiferroelectric phase

x-O-n-alkyl-itols. Substrate Structure and Alkyl Chain Position Influences on Their Liquid Crystalline Properties

1997 ◽  
Vol 34 (4) ◽  
pp. 430
Author(s):  
Ph. Bault ◽  
P. Godé ◽  
G. Gpethals ◽  
B. Harmouch ◽  
P. Martin ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Substrate Structure

scholarly journals Dielectric Properties of Chiral Ferroelectric Liquid Crystalline Compounds with Three Aromatic Rings Connected by Ester Groups

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 473 ◽  
Author(s):  
Malay Kumar Das ◽  
Barnali Barman ◽  
Banani Das ◽  
Věra Hamplová ◽  
Alexey Bubnov
Keyword(s):  
Molecular Structure ◽  
Phase Transition ◽  
Liquid Crystalline ◽  
Alkyl Chain ◽  
Dielectric Strength ◽  
Relaxation Frequency ◽  
Goldstone Mode ◽  
Aromatic Rings ◽  
Structural Variations ◽  
Polar Order

The tilted ferroelectric SmC* phase of three structurally different series having three aromatic rings in the core structure connected by ester groups with different end alkyl chain lengths, all of which are derived from lactic acid, have been observed by broadband dielectric spectroscopy. Introduction of structural variations within the liquid crystalline compounds has led to the formation of chiral nematic N*, or the paraelectric orthogonal SmA* phase at higher temperatures. The dielectric spectra strongly depend both on the temperature as well as the specific molecular structure of the self-assembling compounds possessing the ferroelectric polar order. The results reveal a strong Goldstone mode in the ferroelectric SmC* phase with ~kHz relaxation frequency. In the SmC* phase, the real and imaginary parts of the complex permittivity increase up to certain temperature near the SmC*-N*/SmA* transition and then decrease with increasing temperature, perhaps due to the disruption of the molecular domains at the onset of the SmA*/N* phase transition. The dielectric strength attains a maximum value in the SmC* phase and then decreases near the SmA*/N* phase transition. The dielectric strength is also influenced by the lengths of the alkyl chain and the nature of the connecting unit of the constituent molecules. The relaxation time and the relaxation frequency are found to vary with the molecular structure of the studied ferroelectric compounds.

scholarly journals Synthesis and Mesomorphic Properties of Novel Bent-shaped Naphthyl Diketones

2019 ◽  
Vol 92 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Anđela Buljan ◽  
Anamarija Knežević ◽  
Irena Dokli ◽  
Andreja Lesac
Keyword(s):  
Thermal Behaviour ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Molecular Packing ◽  
Broad Temperature Range ◽  
Structural Modifications ◽  
Temperature Range ◽  
Mesomorphic Properties

The synthesis and liquid-crystalline properties are reported for novel naphthyl-based diketones incorporating variant terminal chains and lateral fluoro- substitution. Newly prepared materials exhibit a broad temperature range of the nematic phase. The study demonstrates how subtle structural modifications can be exploited to alter the efficiency of molecular packing and consequently the thermal behaviour.

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