Electrooptic and dielectric properties of new antiferroelectric liquid crystal mixtures

Two new antiferroelectric liquid crystal mixtures based on optically active hydroxyesters have been studied with respect to their electro-optic and dielectric behavior. The mixtures exhibit only a SmA* phase above SmCa* and show a stable antiferroelectric order over a broad temperature range (≈100°C). Electro-optic as well as dielectric studies suggest that the SmCa*-SmA* transition is second order. In thin cells signs of a sur- face-induced SmC* phase has also been observed. We present the rele- vant characteristics for three different electro-optic modes which could be exploited in these materials, including the very fast linear mode for sub-threshold voltages.