Induction of Antiferroelectric Phases in High Tilt Chiral Smectics by Doping with Bent-Shaped Liquid Crystals

The orthoconic antiferroelectric Sm C* A phase is of high potential for electro-optic applications. Therefore, mixtures of calamitic molecules possessing the Sm C* phase with high tilt angle (Θ ≈ 45°) and bent core compounds have been prepared. The induction of an antiferroelectric phase has been found even at low concentrations of the banana shaped dopants (5–10 mol%), what has been shown by optic, electro-optic and dielectric investigations. In systems where the host materials possessed the cholesteric and ferroelectric phases, the iso-N*-Sm C*-Sm C* A -crystal phase sequence has been observed. New materials with perfluorinated end chains exhibiting the Sm A-Sm C* phase transition have shown antiferroelectric phases enveloping the Sm C* phase when doped with biphenyl based bent molecules. The tilt angle of the host material remained almost unchanged, i.e. in the case where the host compound possessed a tilt of 45° doping with bent core molecules led to the formation of the orthoconic antiferroe...