The ferro-, ferri- and antiferro-electric properties of a series of novel 2- or 3-substituted-alkyl 4-(4′-dodecyloxybiphenyl-4-carbonyloxy)-benzoate esters

Abstract

This paper reports the synthesis of six chiral liquid crystalline 2- or 3-substituted-alkyl 4-(4′-dodecyloxybiphenyl-4-carbonyloxy)benzoates, their mesophase assignments and the phase transition temperatures. All six materials display S∗_A followed by S∗_C phases on cooling from their isotropic liquids. The magnitudes of switched tilt angle, spontaneous polarization, helical twist sense (L.H.) and direction of polarization (P _s(−)) are given for the S∗_C phases. Close inspection of the S∗_C phases revealed that for the six compounds, two showed a ferrielectric (S∗_{C γ}) and an antiferroelectric (S∗_A) subphase, two showed only a ferrielectric subphase and one showed only an antiferroelectric subphase. The field-dependent behaviour of the switched tilt angle of the ferrielectric and antiferroelectric phases of some of the compounds is also presented.