Uniaxially parallel alignment of a smectic a liquid-crystalline rod-coil molecule and its lithium salt complexes using rubbed polyimides

The alignment behavior of thermotropic smectic A liquid-crystalline molecule 1 and its complexes with lithium triflate on the thin films of rubbed polyimides has been examined. Compound 1 has a rod-coil block structure consisting of a tetra(ethylene oxide) chain that is polar and a phenylcyclohexyl mesogen that is nonpolar. The use of a rubbed polyimide having a linear and rigid molecular structure prepared from pyromellitic dianhydride and 1,4-phenylenediamine induces the uniaxially parallel alignment of 1 and its lithium triflate complexes. The lithium salt complexes of compound 1 that exhibit smectic A phases function as two-dimensional ion conductors. The ionic conductivities of the aligned complexes of 1 on the rubbed polyimides were measured by an ac impedance method. Anisotropic ionic conductivities have been observed for the aligned liquid-crystalline lithium salt complexes.