Premium
Spontaneous Birefringence in Layer‐by‐Layer Films of Chitosan and Azo Dye Sunset Yellow
Author(s) -
Santos David Sotero dos,
Bassi Alex,
Misoguti Lino,
Ginani Marconi Floripe,
Oliveira Osvaldo Novais de,
Mendonça Cleber Renato
Publication year - 2002
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 - 10.1002/1521-3927(200211)23:16<975::aid-marc975>3.0.co;2-w
Subject(s) - azobenzene , birefringence , chitosan , materials science , layer (electronics) , layer by layer , isomerization , sunset , optics , molecule , azo compound , chemical engineering , photochemistry , nanotechnology , composite material , chemistry , organic chemistry , polymer , physics , catalysis , engineering
Layer‐by‐layer (LBL) films consisting of layers of the azo dye Sunset Yellow alternated with chitosan display spontaneous birefringence, which is attributed to the film anisotropy imparted by the LBL method. This is unusual for azobenzene‐containing materials as they normally form films with randomly oriented molecules, presenting birefringence only due to photoinduced isomerization cycles. Spontaneous birefringence does not appear in cast films, but occurs for LBL films obtained under various experimental conditions.Chemical structures of (a) Sunset Yellow and (b) chitosan.