The effect of pretransitional phenomena on the characteristics of induced ferroelectric liquid-crystalline systems

Abstract

Abstract The effect of different types of phase transition on the temperature dependence of the helical pitch and the spontaneous polarization is investigated for mixtures of smectic C liquid crystals and a chiral dopant, based on salicylidenanylene derivatives. The observed phenomena are explained by assuming that the temperature dependence of the pitch is connected with the growth of the disclination loops near the second order phase transition, and that the subsurface electric field can unwind the helix in chiral substances with strong piezoelectric effects which occur for large polarization values.