Synthesis and Physical Evaluation of Novel Ferroelectric Materials with High Spontaneous Polarization

Abstract

A large number of ferroelectric dopants incorporating a chiral lactate unit, , have been synthesized and extrapolated values of Ps as high as 160 nC cm⁻² have been found, although many of these compounds did not show any liquid crystal behavior. Terphenyls and laterally fluoro-substituted terphenyls incorporating the chiral lactate unit have also been synthesized, and in one case, a ferroelectric host material with an S_C * phase and a Ps value of 124 nC cm⁻² was obtained.

Compounds containing two chiral units (one of which was a chiral lactate unit) were also synthesized in which the two chiral units were either directly linked or separated by a phenyl ring; the latter compounds gave very high Ps values (199 nC cm⁻²).

The effect of molecular structure on Ps, tilt angle and phase behavior is discussed for both the mono-lactates and the di-chiral compounds.

An outline (with references) of the experimental procedures used to prepare these compounds is also given.