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-tetrafluorophenylene) ethynyl] benzoate and 4 -[(~)-2-methyIbutoxycarbonyl] phenyl 4-(4'-n-heptyloxy-2,3,5,6-tetrafluorobiphenyl-I-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 97T, a melting point of 61°C and a polarization of 5.5 x 10-6C/mZ at temperature of IO'C below curie point.