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Thermosensitive phase transition kinetics of poly( N ‐isopropylacryl amide‐ co ‐acrylamide) microgel aqueous dispersions
Author(s) -
Wang Qin,
Zhao Yanbing,
Xu Huibi,
Yang Xiangliang,
Yang Yajiang
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.29642
Subject(s) - lower critical solution temperature , copolymer , polymer chemistry , materials science , chemical engineering , aqueous solution , kinetics , acrylamide , polymerization , dynamic light scattering , swelling , poly(n isopropylacrylamide) , phase (matter) , polymer , chemistry , composite material , organic chemistry , nanoparticle , nanotechnology , physics , quantum mechanics , engineering
Thermosensitive poly( N ‐isopropylacrylamide‐ co ‐acrylamide) microgel particles were prepared through precipitation polymerization. The diameters of the microgel particles were in the range of 220–270 nm and showed a monodispersion. The lower critical solution temperatures (LCST) of the microgel dispersions were measured by dynamic light scattering and turbidimetric analysis. The results indicated that the LCST increased with an increase of acrylamide (AAm) content in the copolymer composition. The kinetics of the thermosensitive phase transitions of the microgel particles were investigated by time‐course UV–vis spectroscopy. The results indicated that the higher the content of AAm in copolymer composition, the more time is required for equilibrium deswelling and the less time required for equilibrium swelling. In addition, the time required for equilibrium deswelling decreased with an increase of the content of the microgel particles in dispersions. By contrast, the time required for equilibrium swelling increased slightly. Thus, a suitable LCST and time required for equilibrium of phase transition can be achieved by adjusting the molar ratio of the comonomers in the microgels and the content of the microgel particles in dispersions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009