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Poly( N ‐isopropylacrylamide) grafted to a strongly charged backbone: Thermoresponsive behavior in aqueous solution
Author(s) -
Chourdakis N.,
Bokias G.,
Staikos G.
Publication year - 2004
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.20326
Subject(s) - copolymer , poly(n isopropylacrylamide) , aqueous solution , sulfonic acid , acrylic acid , polymer chemistry , lower critical solution temperature , chemistry , materials science , polymer , organic chemistry
The thermoresponsive properties in aqueous solution of the graft copolymer poly(acrylic acid‐ co ‐2‐acrylamido‐2‐methyl propane sulfonic acid)‐ g ‐poly( N ‐isopropylacrylamide) [P(AA‐ co ‐AMPSA)‐ g ‐PNIPAM] were studied and compared to the corresponding behavior of the poly(acrylic acid)‐ g ‐poly( N ‐isopropylacrylamide) (PAA‐ g ‐PNIPAM) graft product. Both products contain about 40% (w/w) of PNIPAM, whereas the backbone, P(AA‐ co ‐AMPSA), of the first copolymer contains about 40% of AMPSA mole units. The strongly charged P(AA‐ co ‐AMPSA)‐ g ‐PNIPAM graft copolymer was water soluble over the whole pH range, whereas the PAA‐ g ‐PNIPAM copolymer precipitated out from water at pH < 4. As a result, the first product exhibited a temperature‐sensitive behavior in a wide pH range, extended in the acidic region, whereas in semidilute aqueous solutions, an important thermothickening behavior was observed, even at low pH (pH = 3.0). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3466–3470, 2004