Switching of ionic conductivities in columnar liquid-crystalline anilinium salts: effects of alkyl chains, ammonium cations and counter anions on thermal properties and switching temperatures

2019 ◽  
Vol 4 (2) ◽  
pp. 342-347 ◽  
Author(s):  
Daniel Kuo ◽  
Bartolome Soberats ◽  
K. R. S. Kumar ◽  
Masafumi Yoshio ◽  
Takahiro Ichikawa ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Ionic Conductivities ◽  
Molecular Structures ◽  
Switching Behavior ◽  
Alkyl Chains ◽  
Ion Conductivities ◽  
Thermal Switching

Effects of molecular structures on the thermal switching behavior of ion conductivities for columnar anilinium liquid crystals have been examined.

scholarly journals Flüssigkristalline Kohlenhydratdithioacetale / Liquid Crystalline Carbohydrate Dithioacetals

1988 ◽  
Vol 43 (7) ◽  
pp. 878-888 ◽  
Author(s):  
Andreas Eckert ◽  
Bernd Kohne ◽  
Klaus Praefcke
Keyword(s):  
Molecular Structure ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
The Other ◽  
Hydroxyl Group ◽  
Melting Behaviour ◽  
Sugar Chain ◽  
Alkyl Chains ◽  
Identical Type ◽  
Sugar Derivatives

Abstract S,S-dialkyl acetals of hexanal and numerous aldoses, tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and D.S.C. Most of these geminal dithioacetals show a complicated melting behaviour and are thermotropic liquid crystal-line, exhibiting only one smectic-like phase of identical type. This mesophase is not miscible with the SAd -Phase of other amphiphilic sugar-based liquid crystals. As shown in a homologues series of D-glucose S,S-dialkylacetal derivatives clearing points are rising as function of growing number n of carbon atoms in their S-alkyl chains. With constant n given a similar trend is observed by varying the length of the polar, hydrophilic sugar units. Regarding stereochemistry the dithioderivatives 5 and 12 of the pentose or hexose series, respectively, with a configuration related to that of D-mannose exhibit relatively the most stable mesophase. However, the most stable mesophase of all investigated sugar dithioderivatives is exhibited by the heptose S,S-dialkylacetal 13. Surprisingly, derivative 10 of L-rhamnose (6-desoxy-L-mannose) - the terminal hydroxyl group in the sugar chain of mannose is missing! -showed to be non-mesomorphic, demonstrating that a terminal hydroxyl group of these sugar derivatives seems to be essential for exhibiting a mesophase. On the other hand, as shown with the dithioderivative 9 of 2-desoxy-D-glucose in comparison to the derivative 8e and 12 of D-glucose or D-mannose, respectively, their clearing points seem to be less, although differently effected if an internal hydroxyl group - for instance here at C-2 - has been stripped off.Melting behaviour as well as thermomesogenic properties of the presented amphiphilic carbo-hydrate liquid crystals in relationship to their molecular structure are discussed in detail.

Structure-Property Relationships of Quinoxaline Based Liquid Crystals

Soft Matter ◽  
2021 ◽  
Author(s):  
Vinod Kumar Vishwakarma ◽  
Achalkumar Ammathnadu Sudhakar
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Quinoxaline Derivatives

Quinoxaline derivatives with different molecular structures stabilizing liquid crystalline self-assembly are discussed in this review. This class of molecules can be systematically modified with careful molecular engineering to achieve different...

scholarly journals Optical investigations and photoactive solar energy applications of new synthesized Schiff base liquid crystal derivatives

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fowzia S. Alamro ◽  
Sobhi M. Gomha ◽  
Mohamed Shaban ◽  
Abeer S. Altowyan ◽  
Tariq Z. Abolibda ◽  
...  
Keyword(s):  
Solar Energy ◽  
Liquid Crystalline ◽  
Molecular Structures ◽  
Light Illumination ◽  
Electrical Measurements ◽  
Scanning Calorimetry ◽  
Energy Applications ◽  
Meta Position ◽  
Chain Group ◽  
Liquid Crystalline Materials

AbstractNew homologues series of liquid crystalline materials namely, (E)-3-methoxy-4-[(p-tolylimino)methyl]phenyl 4-alkloxybenzoates (I-n), were designed and evaluated for their mesomorphic and optical behavior. The prepared series constitutes three members that differ from each other by the terminally attached alkoxy chain group, these vary between 6 and 12 carbons. A laterally OCH3 group is incorporated into the central benzene ring in meta position with respect to the ester moiety. Mesomorphic characterizations of the prepared derivatives are conducted using differential scanning-calorimetry (DSC), polarized optical-microscopy (POM). Molecular structures were elucidated by elemental analyses and NMR spectroscopy. DSC and POM investigations revealed that all the synthesized derivatives are purely nematogenic exhibiting only nematic (N) mesophase, except for the longest chain derivative (I-12) that is dimorphic possesses smectic A and N phases. Moreover, all members of the group have a wide mesomorphic range with high thermal nematic stability. A comparative study was established between the present derivative (I-6) and their previously prepared isomer. The results indicated that the location exchange of the polar compact group (CH3) influences the N mesophase stability and range. The electrical measurements revealed that all synthesized series I-n show Ohmic behaviors with effective electric resistances in the GΩ range. Under white light illumination, the effective electric conductivity for the compound I-8 is five times that obtained in dark conditions. This derivative also showed two direct optical band gaps in the UV and visible light range. In addition, I-6 has band energy gaps of values 1.07 and 2.79 eV, which are suitable for solar energy applications.

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
Sign in / Sign up

Export Citation Format

Share Document