Study on the thermotropic properties of highly fluorinated 1,2,4-oxadiazolylpyridinium salts and their perspective applications as ionic liquid crystals.

A new series of fluorinated salts, iodides and trifluoromethanesulfonates, was synthesized fromperfluoroalkylated 1,2,4-oxadiazolylpyridines. Their thermotropic properties were investigated bycombined temperature resolved small angle and wide angle X-ray scattering, differential scanningcalorimetry and polarised optical microscopy. The UV–visible and photoluminescence propertieswere studied for all compounds. The results showed for two compounds the existence of anenantiotropic mesomorphic smectic liquid crystal phase. All iodides showed thermochromismphenomena suggesting prospective applications in optoelectronics.