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Investigation of pH sensitivity of poly(acrylic acid‐ co ‐acrylamide) hydrogel
Author(s) -
Zhou Xianju,
Weng Lihui,
Chen Qiang,
Zhang Jianming,
Shen Deyan,
Li Zhuchuan,
Shao Manjun,
Xu Jian
Publication year - 2003
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.1207
Subject(s) - environmental scanning electron microscope , acrylic acid , upper critical solution temperature , acrylamide , polymer chemistry , chemical engineering , chemistry , polyelectrolyte , scanning electron microscope , nuclear chemistry , materials science , self healing hydrogels , polymer , copolymer , organic chemistry , composite material , lower critical solution temperature , engineering
It was found that the upper critical solution temperature (UCST) of poly(acrylic acid‐ co ‐acrylamide) hydrogel decreases with increase in pH. The UCST of samples equilibrated in a buffer at pH 2.5 was 33.7 °C, whereas it shifted to below 0 °C when swollen in buffers above pH 10. FT‐IR showed that COOH group of acrylic acid ionized gradually in alkaline media. The morphology change of the hydrogel swollen in different buffers was studied by environmental scanning electron microscopy (ESEM). ESEM images showed that the pore size of the sample increased with increase in pH, and in strongly basic media the three‐dimensional network was replaced by a ‘sausage‐like’ or ‘desert‐like’ structure. A study of the pH‐dependent release of cefazolin sodium was also carried out. Copyright © 2003 Society of Chemical Industry