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Polychromatic light‐emitting conjugated polymer prepared by controlling its structure through active free radical addition
Author(s) -
Zhang JianJun,
Gao Ge,
Dong Wei,
Zhao DaCheng,
Liu FengQi
Publication year - 2008
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2428
Subject(s) - conjugated system , polymer , homo/lumo , materials science , photochemistry , fourier transform infrared spectroscopy , radical , polymer chemistry , fluorescence , chemistry , molecule , organic chemistry , chemical engineering , optics , engineering , physics
BACKGROUND: The HOMO–LUMO energy level width of conjugated polymers can be manipulated by controlling the conjugation length of the polymeric materials in order to adjust their properties in terms of emission of different colors and realize polychromatic displays. In the work reported in this paper azobisisobutyronitrile (AIBN) was used to control the conjugation length of poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐ co ‐(1,4‐phenylene vinylene)] (MEH‐PPV) by free radical addition. In this way a series of MEH‐PPV with various conjugation lengths was obtained. RESULTS: Characterization of MEH‐PPV using 1 H NMR and Fourier transform infrared spectroscopy demonstrated that the cyano groups of AIBN hydrolyzed into carboxyls. The carboxyl free radicals attacked the conjugated double bonds of MEH‐PPV, resulting in a decrease of trans ‐vinylenes and in an increase of cis ‐vinylenes as well as tert ‐methyls on the backbone. Changing the conjugated structure of the polymer caused the peaks of UV and fluorescence spectra to shift to the blue. CONCLUSION: The resulting MEH‐PPV derivatives can emit orange‐red, green and blue light. It is expected that they could be used to prepare PPV‐based materials that could modulate white light emission, by simply blending the PPV derivatives emitting different colors. Copyright © 2008 Society of Chemical Industry