Aliphatic Liquid Crystals with Positive Dielectric Anisotropy
β Scribed by Maged A. Osman; T. Huynh-Ba
- Publisher
- John Wiley and Sons
- Year
- 1984
- Tongue
- German
- Weight
- 301 KB
- Volume
- 67
- Category
- Article
- ISSN
- 0018-019X
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β¦ Synopsis
Abstract
Cyanothylβsubsituted cylohexyl cyclohexanoates, bi(cyclohexanes) and phenyl cyclohexanes were synthisized. Their mesmorphic behaviour is compared to that of the corresponding cyano derivatives. (Cyanoethyl)cyclohexyl cyclohenxanoates show mesmorphic properties in contrast to the corresponding cyano derivative. Separation of the cyano substituent from the rigid core of an anisotropic aliphatic compound by methylene groups enhances the thermodynamic stability of the mesophase. In aromatic compound, the cyanoethyl group leads to lower clearing points. These phenomena are attributed to teh influence of steric effects on the packing density and to the dependence of the clearing point on molecular association.
π SIMILAR VOLUMES
## Abstract Liquid crystals with negative ΞΟ΅ can be obtained by incorporating a cyano group in the terminal alkyl substituent or in an ethylene bridge between the cyclic units of the rigid core. The clearing points of such compounds are higher than those of the corresponding derivatives where the c
## Abstract Stable liquid crystals with negative dielectric anisotropy containing the bicyclo [2.2.2]octyl group were synthesized. The incorporation of this moiety in the molecules increased the thermodynamic stability of the mesophase and lowered the smectic tendency. These new compounds can be us
We report here uniform and defect-free homeotropic alignment of nematic liquid crystal having negative dielectric anisotropy (ΞΞ΅<0) on cleaned substrates, which can be changed to bright state (homogeneous alignment) by applying an electric field. However, non-uniformity in the bright state would not