Ferroelectric Nematic and Smectic

ABSTRACT e some of the key elements of a molecular blueprint and hence of enhancing our chances of realization thus seems particularly timely and is our objective here. In particular we wish to examine the role of molecular shape and of attractive forces in favouring or disfavouring the formation of polar nematics. The current situation is far from encouraging even from a modelling point of view. Fluid polar phases have been found in systems of soft [12] and hard [13] repulsive dipolar spheres and of strongly polar Lennard-- Jones spheres. [14, 15] Polar ordering in these systems is probably connected to the tendency of dipoles to arrange in chains and the lack of orientational bias of the spherical particles. Moreover, at least dipolar hard sphere systems, do not have a liquid phase. [16] Since we are interested in nematic systems with polar order added to the orientational one, we have to resort to non spherical objects. Systems of hard ellipsoids, [17] spherocylinders [13, 18, 19]