Effect of Alkali Metal Ion on the Thermal Properties and the Ionic Conductivity of Discotic Liquid Crystals Containg a DibenzoCrown Ether Unit

Abstract

Ion conductive liquid crystals containing a dibenzocrown ether unit, bis[4,4'(5')-{3,4,5-tris(p-dodecyloxybenzyloxy)benzoyloxymethyl}]dibenzo-14-crown-4 (1) and its corresponding dibenzo-18-crown-6 derivative 2 were prepared. From DSC and thermal optical polarized microscopy, 1 showed only one phase transition from the isotropic to the crystalline phase, and the mixtures of 1 and an equimolar amount of alkali metal ion (Li^+, Na^+) also showed only one phase transition from the isotropic to the amorphous phase on cooling process. From these results, it is realized that 1 and its mixtures with alkali metal ion don't have liquid crystalline phases. On the other hand, 2 has liquid crystalline phases, and the ionic conductivity was increased 1.5 orders of magnitude by the addition of K^+. However the effect of the amounts of K^+ was not observed.