Dielectric study of ferroelectric side-chain liquid crystalline polysiloxanes with broad temperature ranges of the chiral smectic C phase 1. Structure dependence of dielectric relaxation
✍ Scribed by Ging-Ho Hsiue; Rong-Ho Lee; Ru-Jong Jeng; Chin-Shan Chang
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 573 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0887-6266
No coin nor oath required. For personal study only.
✦ Synopsis
The dielectric behavior of a series of ferroelectric side-chain liquid crystalline polysiloxanes containing 1-3 oligooxyethylene units as spacers, and 4-(S)-Z-methyl-l-butyl[ [($-hydroxybiphenyl-4'-yl)]carbonyl]oxy] benzoate or 4-(S) -2-methyl-1 -butyl[ [ (4-hydroxy-biphenyl-4'yl)carbonyl]oxy] -3-fluoro benzoate side groups was studied by broadband dielectric spectroscopy. The increase of the spacer length, and incorporation of a strong dipole moment fluoro-substituent into the mesogenic group, resulted in a decrease of the relaxation activation energy and a n increase in the intensity of the relaxation. Moreover, the relaxation peak of the Goldstone mode has only been observed for the FLCP with a lateral fluorosubstituent. The relationship between the thermal dynamic behavior and chemical structure is discussed in detail. Furthermore, analysis of the dielectric relaxation behavior of these FLCPs showed that the molecular relaxations could be described by the Cole-Cole equation.