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Reversible Photocontrolled Swelling‐Shrinking Behavior of Micron Vesicles Self‐Assembled from Azopyridine‐Containing Diblock Copolymer
Author(s) -
Han Kuo,
Su Wei,
Zhong Mincheng,
Yan Qing,
Luo Yanhua,
Zhang Qijin,
Li Yinmei
Publication year - 2008
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.200800483
Subject(s) - copolymer , swelling , vesicle , amphiphile , raft , polymer chemistry , chain transfer , materials science , photochemistry , azobenzene , tetrahydrofuran , ultraviolet , polymerization , radical polymerization , chemistry , membrane , composite material , organic chemistry , polymer , biochemistry , optoelectronics , solvent
Poly( N ‐isopropylacrylamide)‐ block ‐poly{6‐[4‐(4‐pyridyazo)phenoxy] hexylmethacrylate} (PNIPAM‐ b ‐PAzPy) was synthesized by successive reversible addition‐fragmentation chain transfer (RAFT) polymerization. In a water/tetrahydrofuran (H 2 O/THF) mixture, amphiphilic PNIPAM‐ b ‐PAzPy self‐assembles into giant micro‐vesicles. Upon alternate ultraviolet (UV) and visible light irradiation, obvious reversible swelling‐shrinking of the vesicles was observed directly under an optical microscope. The maximum percentage increase in volume, caused by the UV light, reached 17%. Moreover, the swelling could be adjusted using the UV light power density. The derivation of this effect is due to photoinduced reversible isomerization of azopyridine units in the vesicles.