Antiferroelectric Low Molar Mass Organosiloxane Liquid Crystals: A Phenomenological Model

We have established that the antiferroelectric order observed in low molar mass organosiloxane liquid crystal materials with chiral bi-mesogen molecules is due to the bent conformation of the molecules rather than to co-operative antiferroelectric interactions. The switching between antiferroelectric and ferroelectric order involves a change of conformation of the molecules. We show that in mixtures of antiferroelectric and ferroelectric molecules this concept can be used to vary continuously the threshold field for antiferroelectric switching. We propose a simple model to describe the behaviour of the materials and to predict the threshold field.