Polarization monodomains and electric field response in wedge samples of a ferroelectric nematic liquid crystal.

A ferroelectric nematic (N_F) liquid crystal is formed by highly polar molecules which produce macroscopic electric polarization. The long-range polar ordering leads to a broad range of phenomena that are absent in typical nematics such as the formation of polarization domains, polar surface anchoring, and polar response to the electric field, etc. In this work, we report on the ferroelectric properties of the material abbreviated DIO [1] under different confinement conditions in the presence and absence of an electric field. In cells with the parallel assembly of rubbing directions, the polar mesophase of DIO forms N_F monodomain upon cooling with a rate below 5 ^oC/min if the thickness is less than 5 μm. The monodomain polarization is antiparallel to the rubbing direction and is realigned in the plane of the cell by applying a dc electric field through a system of patterned electrodes. The electric field realignment demonstrates that the in-plane surface anchoring energy is polar with a local minimum for polarization parallel to the rubbing direction and a global minimum for antiparallel alignment. The bulk and surface properties of DIO show that the material is a ferroelectric nematic. The work is supported by NSF grant ECCS-2122399.

1.Nishikawa, et al. Adv. Mater.(2017)29:1702354