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

Pyridinium-based ionic liquid crystals with terminal fluorinated pyrrolidine

“…The 1,2,4-oxadiazolylpyridinium salts with terminal highly fluorinated alkyl chain were reported by Lo Celso [24]. Recently, Li [25] has synthesized fluorinated imidazolium-based dicationic ionic liquid crystals using fluoro-substituents as linking bridges.…”

Ionic Liquid Crystals Based on Pyridinium Salts

“…An interesting example showing how the 3'-or4'-substitution pattern of the pyridinium ring affects the thermal behavior is represented by the iodides and trifluoromethanesulfonates salts derived from perfluoroalkylated 1,2,4-oxadiazolylpyridines 28-31 [36]. Thus, the 3'-substitution derivatives exhibited liquid crystalline properties (SmX phase) on a narrow temperature range, while the corresponding 4'-substitution derivatives were found to pass from the crystalline state straight to the isotropic phase.…”

1,2-Propanediol-linked chiral symmetric and non-symmetric liquid crystal dimers containing trifluoromethyl

“…Chiral liquid crystals (LCs), including chiral smectic phase, [1][2][3][4][5][6] chiral nematic phase, [2,[5][6][7][8][9] cholesteric phase, [4,[10][11][12] blue phase [12][13][14][15] and so on, have attracted much interest because of their unique optical and electrical properties, such as the selective reflection of light, [3,5,7,8,12] thermochromism [16,17] and ferroelectricity. [1,6,18,19] Fluorinated LCs are a class of important LCs for their fascinating properties such as the high polarity, dielectric anisotropy, optical anisotropy and viscoelastic properties.…”