Effect of the external twist on molecular orientation in antiferroelectric liquid crystals.

Abstract

We report on microscopic observations of molecular orientation and layer structure induced by an external twist in antiferroelectric liquid crystals (AFLCs). In a twisted geometry, the smectic layers are formed perpendicular to the surface normal of the cell such that the molecular director experiences twist by twice of intrinsic molecular tilt on going from one surface to the other. It is found that this external twist significantly influences the uniformity of molecular alignment and the characteristics of the double hysteresis inherent to the antiferroelectric order. The resultant electro-optic effect is described within the framework of the field-induced antiferroelectric-ferroelectric phase transition.