Two Dimensionally Ion-Conductive Liquid Crystals of Cholesterol/Tetra(Ethylene Oxide) Block Molecules

ABSTRACT

Two-dimensionally ion-conductive liquid crystals have been simply obtained by self-assembly of a cholesterol/tetra(ethylene oxide) block molecule and lithium triflate. Nanophase-segregation between cholesterol and tetra(ethylene oxide) blocks leads to the formation of a smectic A liquid crystalline phase in a wide range of temperature. A homeotropically aligned lithium salt complex in the smectic A phase shows two-dimensional ionic conductivity. The ionic conductivities parallel to the smectic layers are higher than those perpendicular to the layers. The maximum value of the anisotropy in the ionic conductivity is about 2.4 × 10³ at 30°C.

Keywords:

• anisotropic ion-conduction
• liquid crystals
• macroscopic orientation
• nanophase-segregation

Acknowledgments

Financial support of Grant-in-Aid for Scientific Research on Priority Areas, Scientific Research B, Encouragement of Young Scientists B (No. 15350077) from the Ministry of Education, Culture, Sports, Science, and Technology is gratefully acknowledged. K. K. is thankful for financial support by the Research Fellowships of the Japan Society for the Promotion of Science (JSPS) for Young Scientists.

Notes

^a Transition temperature (°C): Iso = isotropic, S_A = smectic A, S_B = smectic B, S_E = smectic E, S_X = unidentified ordered smectic phases, G = glassy.

^b The concentration of lithium salts is 0.05 mol per oxyethylene unit.

^c Ref. [9].