Chiral Liquid Crystals: Structures, Phases, Effects

Symmetry

关键词: liquid crystal;    chirality;    helicity;    Blue Phases;    Twist Grain Boundary phases;    ferroelectricity;    biological materials;   

DOI  :  10.3390/sym6020444

来源: mdpi

【 摘 要 】

The introduction of chirality, i.e., the lack of mirror symmetry, has a profound effect on liquid crystals, not only on the molecular scale but also on the supermolecular scale and phase. I review these effects, which are related to the formation of supermolecular helicity, the occurrence of novel thermodynamic phases, as well as electro-optic effects which can only be observed in chiral liquid crystalline materials. In particular, I will discuss the formation of helical superstructures in cholesteric, Twist Grain Boundary and ferroelectric phases. As examples for the occurrence of novel phases the Blue Phases and Twist Grain Boundary phases are introduced. Chirality related effects are demonstrated through the occurrence of ferroelectricity in both thermotropic as well as lyotropic liquid crystals. Lack of mirror symmetry is also discussed briefly for some biopolymers such as cellulose and DNA, together with its influence on liquid crystalline behavior.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.