Synthesis and properties of new materials with banana-shaped achiral cores and chiral end groups
| Autor: | Liang-Chy Chien, E-Joon Choi, Sung-Tae Shin, Wang-Cheol Zin, Chong-Kwang Lee, Tae-Sung Kim, Jae-Hoon Kim, Dae-Cheol Kim, Soon-Sik Kwon |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | Liquid Crystals. 30:1401-1406 |
| ISSN: | 1366-5855 0267-8292 |
| DOI: | 10.1080/02678290310001621930 |
| Popis: | New chiral bent-core mesogens, derivatives of 1,3-phenylene bis[4-(alkanyloxyphenyliminomethyl)benzoate], were synthesized with variation of a substituent (X=F, Cl); their antiferroelectric properties are described. The mesomorphic and switching properties were characterized by differential scanning calorimetry, polarizing optical microscopy, triangular wave method, and X-ray diffractometry in the small and wide angle regions. The presence of chiral tails at the terminals of side wings in the bent-core molecules induced a decrease in transition temperature and formation of the switchable SmC* phase in the melt. In addition, the introduction of a lateral halogen substituent in the Schiff's base moiety prevented the regular stacking of the molecules, resulting in the formation of very complex optical textures. The smectic phase with F-substituted PBFDOB and Cl-substituted PBCDOB showed layer spacings of 39 and 38.5 A, respectively, corresponding to the end-to-end distance of molecules with a bent conformati... |
| Databáze: | OpenAIRE |
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