Properties and Design of Chiral Azobenzenes

Azobenzene systems represent very attractive phototriggers in Ch LCs, thanks to their resistance to photofatigue, the simplicity of the molecules, and the ease of modification of their molecular structures. This chapter first describes helical twisting ability of chiral azobenzene compounds by focusing the structural effects on HTP as well as photochemical change in HTP, and then phototuning of helical structures of Ch LCs through the trans-cis photoisomerization of the chiral azobenzene compounds for applications to optical devices. 

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Azobenzenes have simple chemical structures and exhibit simple photoisomerization between the trans- and cis form. However, they can really provide various photofunctions by their combination with sophisticated systems such as Ch LCs. The Ch LCs have a good potential for display applications, because they show interesting optical properties depending on the helical structures and the textures. Many types of optical materials can be created by the use of the photoisomerization of chiral azobenzenes in the Ch LCs. New ideas, including design of molecules and systems, may allow us for future materials not only in the field of optics but also in other fields. 

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