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 22 , and the maximum h values are in the range 23 ‡-28 ‡.