Thermally irreversible photoinduced shift of selective light reflection in 1D cholesteric photonic structure

Design and synthesis of photosensitive 1D photonic system based on cholesteric liquid crystalline polymer will be presented. The photosensitivity and chirality is provided by a novel chiral hydrazone photochromic moiety covalently boud to the polymer backbone of a comb-shaped copolymer. Combination of the chirality and photosensitivity enabled reversible photomanipulation of the helical pitch of the supramolecular cholesteric structure resulting in material with a tunable selective reflection of circularly polarized light of the same helical sense as the chiral structure. In contrast to many other photochromic systems based on E-Z isomerization, the E and Z isomers of hydrazone photochromic group are kinetically stable that enable to achieve a pure photoinduced switch without any dark relaxation at any temperatures