Ferroelectrically Switchable Axial Polarization in Columnar Liquid Crystalline Phases

Abstract

Recently, ferroelectrically switchable columnar LCs have drawn a great deal of attention for their generation of rich polarization domains. Because of their unique dielectric and self‐assembly properties, they are considered to be a promising material for the design of sensors and ultra‐high memory devices. Herein, ferroelectrically switchable LCs by using ester, amide, and 1,2,3‐triazole groups are reviewed. Most of them do not exhibit genuine ferroelectricity owing to the low energy barrier between the two polar states. The intermolecular interactions between polar groups strongly affect the switchability and stability of polarization. Therefore, it is challenging to balance these two competing factors to improve the ferroelectric function in columnar LCs. Overall, additional effort, including LC design and device fabrication, should be made to optimize the material performance for practical applications in the future.

Understanding the remarkable difference in liquid crystal behaviour between secondary and tertiary amides: the synthesis and characterisation of new benzanilide-based liquid crystal dimers

“…These systems tend to predominantly form smectic phases, again attributed to intermolecular hydrogen bonding between the amide groups. Indeed, the use of amide groups in structures such as benzene tricarboxamides (BTA) [19][20][21][22] , hydrazine derivatives [23][24][25][26][27][28] , or peptide residues [29][30][31] promotes columnar liquid crystal phases in which hydrogen bonding stabilises the columns.…”

Electric-Field-Induced Chirality in Columnar Liquid Crystals

“…In cases with propeller types of structures, the small chiral biases have been observed to promote cooperative helical columnar phases . Exotic helical superstructures have proven interesting, and several research groups have recently demonstrated unusual electro-optical behavior, chiro-optical properties, ferroelectricity, or exceptional nonlinear optical properties. − …”

Chiral Self-Sorting and the Realization of Ferroelectricity in the Columnar Liquid Crystal Phase of an Optically Inactive N,N′-Diphenylurea Derivative Possessing Six (±)-Citronellyl Groups

“…Recently, axially polar ferroelectric columnar liquid crystal (AP-FCLC) phases (Figure ), in which the polarity along the column axis is induced by applying an electric field and is maintained after removal of the electric field, have been increasingly studied. − In the columnar liquid crystal (LC) phase, the polar directions of the molecules (Figure a) are fixed to generate a polar column (Figure b) by intermolecular steric interactions − or intermolecular hydrogen bonding between the groups such as amide, ,− urea, − triazole, and vinylidene fluoride oligomer (VDFO) groups. The polar columns that are self-organized into a nonpolar state (Figure c) are polarized by applying an electric field, and the induced columnar polarities are switched (Figure d,e) by changing the directions of the applied electric field.…”