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Thermal and Photochemical Control of Molecular Orientation of Azo‐Functionalized Polymer Liquid Crystals and Application for Photo‐Rewritable Paper
Author(s) -
Moritsugu Masaki,
Ishikawa Takeru,
Kawata Tetsuro,
Ogata Tomonari,
Kuwahara Yutaka,
Kurihara Seiji
Publication year - 2011
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201100244
Subject(s) - polymer , materials science , orientation (vector space) , photochemistry , liquid crystal , thermal , polymer chemistry , optics , chemical engineering , optoelectronics , chemistry , composite material , physics , geometry , mathematics , meteorology , engineering
A photo‐responsive multi‐bilayered film consisting of azobenzene polymer liquid crystals (PA6Az1) and poly(vinyl alcohol) (PVA) has been prepared on a glass substrate by alternate spin coating of the polymer solutions. The reflectivity of the multi‐bilayered film disappears by annealing at 80 °C. The disappearance of the reflection by the annealing is related to the thermal out‐of‐plane molecular orientation of PA6Az1 even in the multi‐bilayered film, which leads to a very small difference in refractive indices between PA6Az1 and PVA. The reflectance of the multi‐bilayered film is increased again by UV irradiation because of the transformation from the out‐of‐plane orientation to an in‐plane random orientation. In this way, on–off switching of the reflection is achieved by combination of the thermally spontaneous out‐of‐plane molecular orientation and following photoisomerization of PA6Az1 comprising the multi‐bilayered film.