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Experiments and simulation of pH‐responsive N ‐isopropylacrylamide–acrylic acid copolymer hydrogels
Author(s) -
Tao Yong,
Zhao JiongXin,
Wu ChengXun
Publication year - 2006
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.23733
Subject(s) - copolymer , self healing hydrogels , acrylic acid , polymer chemistry , ionic strength , swelling , radical polymerization , ionic bonding , poly(n isopropylacrylamide) , dissociation (chemistry) , polymerization , chemical engineering , chemistry , materials science , polymer , composite material , aqueous solution , organic chemistry , ion , engineering
In this study, N ‐isopropylacrylamide–acrylic acid (NIPAAm–AAc) copolymer hydrogels were synthesized by radical polymerization. The equilibrium and dynamic water uptake of these copolymer hydrogels were investigated as a function of acrylic acid content of copolymer, pH, and temperature. The pH‐dependent swelling ratio of the hydrogels was distinguishable between two pH‐modulating methods. In addition, a modified thermodynamic simulation that is able to predict pH‐dependent swelling of polyanionic gels was developed. In the simulation, the influence of ionic strength on dissociation of carboxyl groups was taken into consideration. Also a new relation between Debye length and volume change of gels was derived from the approximation used in derivation of ionic osmotic pressure. The predictions from this modified equation were reasonably good compared with experiments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 323–330, 2006