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Dynamic Control of Full‐Colored Emission and Quenching of Photoresponsive Conjugated Polymers by Photostimuli
Author(s) -
Watanabe Kazuyoshi,
Hayasaka Hiroyuki,
Miyashita Tatsuaki,
Ueda Kenta,
Akagi Kazuo
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201500136
Subject(s) - fluorescence , conjugated system , materials science , photochemistry , polymer , quenching (fluorescence) , photoisomerization , photochromism , polyfluorene , visible spectrum , copolymer , side chain , chemical engineering , isomerization , optoelectronics , nanotechnology , optics , organic chemistry , chemistry , composite material , catalysis , engineering , physics
A series of photoresponsive and full‐colored fluorescent conjugated copolymers is synthesized by combining phenylene‐ and thienylene‐based main chains with photochromic dithienylethene (DE) side chains. Solutions and cast films of the polymers exhibit various colored fluorescence in visible wavelengths of 400−700 nm corresponding to emissions of the conjugated main chain. The fluorescence is reversibly photoswitched between emission and quenching through DE photoisomerization using external stimuli from ultraviolet and visible light irradiation. The reprecipitation method with ultrasonication enables the polymers to form spherical aggregates with diameters of 20−70 nm in water. After investigating and comparing the optical properties, the resulting nanosphere solutions are assumed to exist in an intermediate state between an isolated state (i.e., in solution) and an aggregated state in cast film. The majority of the nanosphere solutions also exhibit the same photoswitchable fluorescence behavior as those in the solutions and the cast films. The results demonstrate that the visible fluorescence of the conjugated copolymers is reversibly switchable between emission and quenching using the photoisomerizing DE side chain regardless of the fluorescent colors and the polymer chain aggregation.