Synthesis and properties of new materials with banana-shaped achiral cores and chiral end groups
SCIE
SCOPUS
- Title
- Synthesis and properties of new materials with banana-shaped achiral cores and chiral end groups
- Authors
- Lee, CK; Kwon, SS; Kim, TS; Choi, EJ; Shin, ST; Zin, WC; Kim, DC; Kim, JH; Chien, LC
- Date Issued
- 2003-12
- Publisher
- TAYLOR & FRANCIS LTD
- Abstract
- New chiral bent-core mesogens, derivatives of 1,3-phenylene bis[4-(alkanyloxyphenylimino-methyl)benzoate], were synthesized with variation of a substituent (X = F, Cl); their antiferro-electric 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 Angstrom, respectively, corresponding to the end-to-end distance of molecules with a bent conformation. Significantly, the smectic phases of PBFDOB and PBCDOB exhibited a period of 179.5 and 131 Angstrom, respectively, compatible with a helical structure with periodicity about 4.6 and 3.4 times the layer spacings.
- Keywords
- SMECTIC LIQUID-CRYSTALS; MOLECULES; PHASE
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/29782
- DOI
- 10.1080/02678290310001621930
- ISSN
- 0267-8292
- Article Type
- Article
- Citation
- LIQUID CRYSTALS, vol. 30, no. 12, page. 1401 - 1406, 2003-12
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