Mesomorphic properties and spontaneous polarization of ferroelectric liquid crystal mixtures based on chiral dopants synthesized by chiral hydroboration

Abstract

Chiral hydroboration has been used to synthesize a range of chiral dopants for ferroelectric mixtures. Chirality was introduced into simple systems which were then subject to palladium-catalysed cross-coupling reactions to generate the final chiral materials for use in ferroelectric mixtures. The dopants have a polar group at the chiral centre which forms part of a cyclohexane ring. The combination of the polarity and restricted rotation at a chiral centre was expected to generate chiral dopants with high values of spontaneous polarization. Ferroelectric mixtures were formulated and evaluated for transition temperatures, spontaneous polarization and tilt angle. The synthetic routes allow for the efficient introduction of a wide range of functional groups at a chiral centre that are conducive to high values of spontaneous polarization.