Hydrogen-bonded ionic liquid crystals based on multi-armed structure: synthesis and characterization

A new type of six-armed pi-conjugated structure was built up from benzene as the central core and electron-rich triazine rings as the peripheral group. The hexasubstituted product was liquid and did not exhibit any liquid crystal properties while the equimolar mixtures in 1:1 ratio of the hexasubstituted compound and 4-(dodecyloxy)benzoic acid resulted in an organic salt exhibiting a columnar mesophase characterized with a dendritic growing texture. Examination of the relationship between structure and properties and the presence of the number of carbon atoms in the alkyl chain suggested that, the higher increase led to the phase transition at low temperature to form a columnar mesophase as an ionic liquid crystal composed of cations and anions. These are often stabilized by resonance with strongly delocalized charges. The liquid crystalline properties of the organic salt were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM).