Ferroelectricity of Novel Liquid Crystals with Tetrafluoro-Phenylene and Biphenylene

Abstract

Ferroelectric properties were investigated by plotting hysteresis loops of spontaneous polarization versus field with sine waveform for 4′-[(s)-2-methylbutoxycarbonyl] phenyl 4′-[(4-n-heptyloxyl-2, 3, 5, 6-tetrafluorophenyl-l-ethynyl] benzoate and 4′-[(s)-2-methylbutoxycarbonyl] phenyl 4-(4′-n-heptyloxy-2, 3, 5, 6-tetrafluorobiphenyl-l-ethynyl) benzoate, respectively. The latter shows enantiotropic mesophases of crystal, chiral smectic C, smectic A. cholesteric and isotropic states. It also has a chiral smectic C temperature range of 97°C, a melting point of 61°C and a polarization of 5.5 × 10⁻⁶C/m² at temperature of 10°C below curie point.

Key Words:

• Smectic
• chiral
• ferroelectric
• tilt
• polarization
• tetrafluorobiphenylene