Synthesis and properties of some novel high birefringence phenylacetylene liquid crystal materials with lateral substituents

Citation
C. Sekine et al., Synthesis and properties of some novel high birefringence phenylacetylene liquid crystal materials with lateral substituents, LIQ CRYST, 28(9), 2001, pp. 1375-1387
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
LIQUID CRYSTALS
ISSN journal
0267-8292 → ACNP
Volume
28
Issue
9
Year of publication
2001
Pages
1375 - 1387
Database
ISI
SICI code
0267-8292(200109)28:9<1375:SAPOSN>2.0.ZU;2-O
Abstract
We have synthesized and investigated new 3-ring phenylacetylene liquid crys tals with high birefringence values (Deltan) to improve the nematic tempera ture range while retaining a high optical anisotropy. In the case of modify ing the terminal ring, the introduction of branched alkoxy chains, fluorine or methyl groups shifted the nematic phase to lower temperatures. In order to minimize the influence of the substituent on On, the incorporation of l ateral methyl groups was chosen as the most profitable method for obtaining wide and low temperature nematic phases. With these results in mind, we st udied the effect of the position of the methyl group on the physical proper ties. The most effective methyl position for improving the nematic temperat ure range was on the central ring. From the standpoint of obtaining high An values and low viscosity, the central ring was also the best position.