Molecular Crystals and Liquid Crystals, Vol.443, 69-78, 2005
Photon mode color display device by means of isomerization of chiral azobenzene
Photochromic compounds having plural chiral sites as well as azobenzene groups in a molecule was synthesized by reacting 4-, and 3-, 2-carboxy-4'-hexyloxyazobenzenes with isosorbide, and isomannide. A cholesteric liquid crystal (Ch LC) was induced by adding each chiral azobenzene compound in a nematic LC. Most azo dyes showed photochemical decrease in the helical twisting power (HTP ) by UV irradiation. The change in HTP was related to the photochemical change in the molecular shape. Reversible control of the reflection wavelength of the Ch LC was achieved over a whole range of visible region by irradiation of UV and visible light.
Keywords:chiral azobenzene;cholesteric liquid crystal;photoisomerization;selective reflection,switching