Ferroelectric Smectic Liquid Crystals

• Published in: Crystals (Basel) Vol. 14; no. 4; p. 350
• Main Author: Yoshizawa, Atsushi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2024
• Subjects: 13C NMR; antiferroelectric liquid crystals; Crystal defects; de Vries smectic A; display; Dynamic models; Electric fields; ferroelectric liquid crystals; Ferroelectric materials; Ferroelectricity; Iron constituents; LCDs; Liquid crystal displays; Network switches; NMR; Nuclear magnetic resonance; Optical switching; Phase transitions; Phases; Smectic liquid crystals; Symmetry; Germany
• ISSN: 2073-4352; 2073-4352
• DOI: 10.3390/cryst14040350

Since the discovery of the first ferroelectric liquid crystal (FLC) in the chiral smectic C (SmC*) phase, ferroelectricity in liquid crystals has attracted much attention due to not only the fundamental interest but also the applications. This review focuses on the evolution of the design concept for ferroelectric smectic liquid crystals. It progresses from considering macroscopic phase symmetry to designing intermolecular interactions. For the purpose of understanding the molecular organization in smectic phases, we propose a dynamic model of constituent molecules in the smectic A (SmA) and SmC* phases based on 13C NMR studies. Then, we follow the structure–property relationship in ferroelectric SmC* liquid crystals for FLC displays. We reconsider de Vries-like materials that can provide defect-free alignment. We pay attention to the electro-optical switching in the chiral de Vries smectic A phase. Finally, we show several liquid crystals exhibiting polar smectic A phases and discuss how the polar order occurs in the highest symmetric smectic A phase.