Contributions of the molecular species to the magnitude of the spontaneous polarization in ferroelectric liquid crystals

Abstract

In certain ferroelectric liquid crystals that contain the biphenylyl moiety, the spontaneous polarization undergoes a change in direction relative to the optical axis of the system as a function of temperature. Consequently, at a characteristic temperature for a particular derivative, the polarization vanishes. A model based on the presence of at least two species, interconvertible via an activation barrier is proposed to explain this extraordinary behaviour of the polarization. It is suggested that these species are most likely identified with the rotational conformers of these materials while they are in their liquid-crystalline states.