Ion-Conductive Liquid Crystals : Formation of Triply Nano-Phase Separated Structures by the Introduction of Perfluoroalkyl Moieties

Abstract

We have synthesized dimeric compounds F8A13 and F8B13 consisting of perfluoroalkyl-substituted mesogenic cores and poly(ethylene oxide)s (PEOs). The compounds F8A13 and F8B13 have been complexed with lithium triflate. The complexes of F8A13 show the sinecite A and C phases by the nano-level phase segregation of perfluoroalkyl, mesogen, and PEO moieties. The complexes of F8B13 exhibit not only the smectic phases, but also the hexagonal columnar phases. The S_A-Iso transition temperatures of F8A13 and F8B13 are higher than those of the corresponding alkyl-substituted compounds of 8A13 and 8B13, which suggests that the layer structures are stabilized by the introduction of perfluoroalkyl moieties. The ion conductivity of F8A13 is higher than that of 8A13 in the direction parallel to the smectic layer structures. The formation of thermally stable smectic bilayer may contribute to the higher ion conductivity of F8A13.