Measurement of anisotropic ion conduction in liquid crystalline states having polyether segments

Ion conductive layer of poly(ethylene oxide) (PEO) chain was constructed wi th the aid of the alignment of liquid crystalline molecules. The liquid cry stal containing the PEO structure shows enantiotropic smectic phases fi om 20 to about 200 degreesC. This liquid crystalline molecule can stand perpen dicularly and make homeotropic phase on comb-shaped Au electrodes deposited on the glass substrate. Since the liquid crystal was in the single domain (homeotropic) only on glass and gold surfaces, the aligned oxyethylene unit in the liquid crystal should form quasi-ion-conductive-layer which is para llel to the glass surface. The ionic conductivity parallel to the conductin g layer of this liquid crystal containing lithium triflate was 10(-3)S/cm a t 85 degreesC which was 10(3) times higher than that for multi-domain phase observed on the indium tin oxide (ITO) electrodes. This value is quite hig h as that in highly viscous matrix. Such high ionic conductivity was only o bserved in the liquid crystal (smectic) phase, and it decreased at and abov e the isotropic temperature. In the isotropic phase, no successive and effe ctive ion conductive layer existed resulting in the lower ionic conductivit y. Copyright (C) 2000 John Wiley & Sons, Ltd.