Ferro-, ferri- and antiferro-electric behaviour in a bent-shaped mesogen

Article abstract of DOI:10.1039/b000128g

The synthesis of a novel bent-shaped, four-ring thiophene-based chiral liquid crystalline ester derived from 5-(4-n-decyloxyphenyl)thiophene-2- carboxylic acid and (S)-1-methylheptyl 4'-hydroxybiphenyl-4-carboxylate is reported, i.e., (S)-4'-(1-methylheptyloxycarbonyl)biphenyl-4-yl 5-(4-n- decyloxyphenyl)thiophene-2-carboxylate. Optical microscopy, differential scanning calorimetry, miscibility study, and complementary electro-optical and current response studies reveal the existence of the SmA*, SmC* ferroelectric, SmC* ferrielectric, SmC* antiferroelectric and SmI* antiferroelectric phase types. Another mesophase type possibly exists below SmI* antiferroelectric which generates a rapid electro-optic response. Comparison with the analogous three-ring compound, i.e., (S)-4-(1- methylheptyloxycarbonyl)phenyl 5-(4-n-decyloxyphenyl)thiophene-2-carboxylate increases the thermal stability by 95.8 °C and the SmI* antiferroelectric phase is observed in addition.