Ferroelectric liquid crystals with a thioester linking group positioned at the chiral tail

Abstract

A homologous series of chiral thioesters, hexyl (2S)-2-[6-(4-alkanoyloxyphenyl)benzoyloxy-2′-naphthyl]thiopropionates, HnPBNTP (n=7–11) was synthesized, and the mesophases and electro-optical properties were studied. All the materials possess a ferroelectric SmC* phase, which was confirmed by the switching current behaviour. It was found that compounds with a shorter alkyl chain length (n=7–9) displayed SmA* and SmC* phases, while, compounds with a longer alkyl chain length (n=10 and 11), displayed the SmC* phase exclusively. Spontaneous polarization and apparent tilt angle were also measured. The maximum P _s values are in the range 15–26 nC cm⁻², and the maximum θ values are in the range 23°–28°.