Syntheses and Physical Properties of Ferrocene Derivatives (X) Dielectric Study of Liquid Crystalline Ferrocene Derivatives Containing Cholesteryl Group as a Mesogen

Abstract

Dielectric constant and loss measurements were made using a LCR meter at different frequencies from 100 Hz to 100 kHz with the aid of a personal computer. The samples used were ferrocene derivatives containing the mesogenic group, [4-[ω-(cholesteryloxycarbonyl)alkoxy-carbonyl]phenyl]ferrocene of which carbon atoms number in the alkyl chain as a flexible spacer are 2, 4, 6, 8, 10, 11 and 15. These samples showed liquid crystallinity. The phase transition points were clearly observed in the curves of the temperature dependence of the dielectric constant. Activation energy was estimated from the Williams–Landel–Ferry (WLF) equation. The result obtained suggests that the molecular motion in the liquid crystalline phase is nearly the same as that of main chain segments of the polymers.

Key Words:

• Dielectric constant
• dielectric dispersion
• ferrocene derivative
• metallomesogen
• liquid crystal