The Synthesis of Ferroelectric Liquid Crystal Materials

Abstract

Six compounds with the general structure

were synthesized, where R is a n-alkyl or n-alkoxy group of seven to twelve carbon atoms, R’ is an alkyl group of three to five carbon atoms, and PH is a phenyl ring. The synthesis procedure is discussed and structural assignments were confirmed by proton-and carbon-13 NMR spectroscopy. The liquid crystal behavior of these compounds was evaluated by DTA and polarized microscope. We discovered that all of them have liquid crystal phases and five out of six have a smectic C* phase with a wide temperature range. The identification of the smectic C* phase was confirmed by observing the response of liquid crystal to an applied train of square pulses with alternating polarity.

Mixtures of these compounds were also prepared and found to be useful as fast switching ferroelectric materials with a suitable temperature range.