Ferroelectric liquid crystals derived from trans-p-n-alkoxycinnamic acids

Abstract

Two series of compounds are prepared using trans-p-n-alkoxycinnamic acids with (2S)-2-chloro-4-methylpentanol and (2S,3S)-2-chloro-3-methylpentanol. Most of the higher homologues in the two series of compounds exhibit a chiral smectic C (S_C) phase at relatively low temperatures and a smectic A (S_A) phase. Some of the lower homologues show a chiral nematic and a blue phase in addition to S_C and S_A phases. The liquid crystalline behaviour of the two series of compounds are quite similar. Some of these compounds have a fairly high value for the spontaneous polarisation which has been measured as a function of temperature. The mesomorphic properties of these two series of compounds have also been compared with esters derived from trans-p-n—alkoxycinnamic acids and (S)-2-chloro-4-methylpentanoic acid and (2S, 3S)-2-chloro-3-methyl-pentanoic acid.