New azobenzene-based chiral-photochromic substances with thermally stable Z-isomers and their use for the induction of a cholesteric mesophase with a phototunable helix pitch

0435954 - FZÚ 2015 RIV GB eng J - Journal Article
Bobrovsky, A. - Ryabchun, A. - Cigl, Martin - Hamplová, Věra - Kašpar, Miroslav - Hampl, F. - Shibaev, V.
New azobenzene-based chiral-photochromic substances with thermally stable Z-isomers and their use for the induction of a cholesteric mesophase with a phototunable helix pitch.
Journal of Materials Chemistry C. Roč. 26, č. 40 (2014), s. 8622-8629. ISSN 2050-7526. E-ISSN 2050-7534
R&D Projects: GA ČR GA13-14133S; GA ČR(CZ) GAP204/11/0723
Institutional support: RVO:68378271
Keywords : photosensitive * liquid crystal * azo * selective reflection
Subject RIV: JI - Composite Materials
Impact factor: 4.696, year: 2014

Novel photosensitive azobenzene-containing substances with sorbitol- and lactate-based chiral fragments were synthesized to serve as chiral-photochromic dopants in cholesteric mixtures. Owing to the presence of chlorine or methyl lateral substituents in the azobenzene fragment of the dopants, the photoinduced Z-form of their molecules is highly stable. The photooptical properties of the prepared cholesteric mixtures were studied and it was shown that UV-irradiation of the planarly-oriented films results in a shift of the selective light reflection wavelength to a long-wavelength spectral region due to E–Z isomerization of the azobenzene moieties. It was found that this value is almost two orders of magnitude less in comparison with the non-substituted chiral-photochromic dopant also studied in this work. The obtained results demonstrate the promising properties of the synthesized compounds for creation of novel photoswitchable cholesteric materials.
Permanent Link: http://hdl.handle.net/11104/0239755