Asymmetrical Azobenzene Liquid Crystals with High Birefringence Prepared via Click Chemistry

Abstract

Asymmetrical azobenzene liquid crystals with high birefringence were prepared via the click chemistry method. The chemical structures of the synthetic intermediates and compounds were confirmed by FT-IR and ¹H-NMR. The liquid crystal behavior, including transition temperatures and phase sequences, were investigated by DSC and POM. The effect of the alkyl substituents on liquid crystal behavior is discussed in detail. Then, the birefringence values of the liquid crystals were measured using polarizing light interferometry method. Moreover, the characteristics of selective reflection, which was associated with the value of birefringence, were studied.

Keywords:

• Azobenzene
• birefringence
• click chemistry
• liquid crystal
• selective reflection

Acknowledgments

This work was supported by Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2013JQ8043); Postdoctoral Science Foundation of China (Grant No. 2013M542323); Postdoctoral Science Foundation of Shaanxi Province, China; Scholastic Science Research Foundation of Xijing University (Grant No. XJ120230 and XJ120233).