A homologous series of chiral swallow-tailed materials possessing an antiferroelectric phase with V-shaped switching property

Abstract

A homologous series of chiral swallow-tailed materials, 1-ethylpropyl (S)-2-{6-[4-(4′-alkoxyphenyl)benzoyloxy]-2-naphthyl}propionates EPmPBNP (m = 8-14), was prepared for investigating the effect of non-chiral alkyl chain length on the electro-optical response of the antiferroelectric phase. With the exception of EP8PBNP which shows monotropic SmC*A phase, the materials show an enantiotropic phase sequence of BPII-N*-TGBA*-SmA*-SmC*A. The maximum spontaneous polarization measured for these materials in the antiferroelectric phase were in the approximate range 20-30 nC cm−2, indicating that the materials possess low polarity. The electro-optic responses measured for the materials in polyimide film-coated homogeneously aligned cells, displayed a thresholdless V-shaped switching property. Our results clearly demonstrate that the non-chiral alkyl chain lengths have no effect on the appearance of V-shaped switching in antiferroelectric phase, but that the applied frequency and cell thickness significantly affect switching behaviours.