Liquid crystals banana design

This volume of Topics in Stereochemistry could not be complete without hearing about ferroelectric liquid crystals, where chirality is the essential element behind the wide interest in this mesogenic state. In Chapter 8, Walba, a pioneering contributor to this area, provides a historical overview of the earlier key developments in this field and leads us to the discovery of the unique banana phases. This discussion is followed by a view of the most recent results, which involve, among others, the directed design of chiral ferroelectric banana phases, which display spontaneous polar symmetry breaking in a smectic liquid crystal. 

Shen, D. Diele, S. Pelzl, G. Wirth, I. Tschierske, C. Designing banana-shaped liquid crystals without Schiff s base units m-terphenyls, 2,6-diphenylpyridines and V-shaped tolane derivatives. J. Mater. Chem. 1999, 9, 661-672. 

Keith, C. Reddy, R. A. Hahn, H. Lang, H. Tschierske, C. The carbosilane unit as a stable building block for liquid crystal design a new class of ferroelectric switching banana-shaped mesogens. Chem.Commun. 2004,18, 1898-1899. 

Let me emphasize at the end of this chapter that there is nothing particular about the banana shape. What is inherent in the banana shape is that it reduces the symmetry of the molecule and thus was able to reduce the symmetry of the crystal structure, which is a collection of these molecules. Thus, molecules with other shapes, for example, similar to fans or hats, could be designed, too. These low-symmetry molecules can also form these unusual structures if they conform with the general requirements for liquid crystal orientation. Thus, it can be said that there is still room for the development liquid crystal molecules and liquid crystal materials. 

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