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Induction of smectic layering in nematic liquid crystals using immiscible components IV. The effect of bulky lateral carboxyl substituents on the thermotropic behaviour of 2,5-bis[4-(n-perfluoroheptyloctyloxy)benzoyloxy]toluene.
- Source :
- Liquid Crystals; Jul2001, Vol. 28 Issue 7, p991-1001, 11p, 4 Black and White Photographs, 2 Diagrams, 2 Charts, 5 Graphs
- Publication Year :
- 2001
-
Abstract
- Bulky lateral carboxylate substituents were introduced at the benzylic position of 2,5-bis[4-(n-perfluoroheptyloctyloxy)benzoyloxy]toluene by esterification of the corresponding benzyl bromide with potassium carboxylates. In spite of the bulky lateral substituents, none of the 2,5-bis[4-(n-perfluoroheptyloctyloxy)benzoyloxy]benzyl carboxylates exhibit a nematic mesophase in addition to, or instead of, the smectic mesophases. All of the crystalline and SmC-SmA transition temperatures and, with the exception of the 9-anthracene carboxylate derivative, all of the isotropization temperatures of the resulting 2,5-bis[4-(n-perfluoroheptyloctyloxy)benzoyloxy]benzyl carboxylates are lower than those of the parent toluene compound. The SmC-SmA transition decreases the most, thereby stabilizing the SmA mesophase. In most cases, the SmC mesophase is destabilized from an enantiotropic to a monotropic mesophase. There is no correlation between any of the transition temperatures and the size of the lateral substituent. [ABSTRACT FROM AUTHOR]
- Subjects :
- CARBOXYLIC acids
PHASE transitions
TOLUENE
Subjects
Details
- Language :
- English
- ISSN :
- 02678292
- Volume :
- 28
- Issue :
- 7
- Database :
- Complementary Index
- Journal :
- Liquid Crystals
- Publication Type :
- Academic Journal
- Accession number :
- 4975037
- Full Text :
- https://doi.org/10.1080/02678290110039471