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Swelling–shrinking hysteresis of poly( N ‐isopropylacrylamide) gels in sodium dodecylbenzenesulfonate solutions
Author(s) -
Sayil Çigdem,
Okay Oguz
Publication year - 2001
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.2289
Subject(s) - sodium dodecylbenzenesulfonate , swelling , poly(n isopropylacrylamide) , aqueous solution , polymer chemistry , chemical engineering , self healing hydrogels , hysteresis , ionic bonding , comonomer , materials science , lower critical solution temperature , polyelectrolyte , chemistry , sodium , copolymer , composite material , ion , organic chemistry , polymer , physics , quantum mechanics , engineering
The swelling and shrinking behaviors of a series of poly( N ‐isopropylacrylamide) (PNIPA) hydrogels are studied in aqueous solutions of sodium dodecylbenzenesulfonate (SDBS). Between 0 and 3 mol % 2‐acrylamido‐2‐methylpropanesulfonic acid sodium salt (AMPS) is used as an ionic comonomer in the hydrogel synthesis. It is shown that the collapsed PNIPA gels in water at 52°C start to swell above a critical SDBS concentration in the external solution. This critical concentration decreases as the ionic group content of PNIPA gel increases. A comparison of the swelling and shrinking experiments in SDBS solutions indicates strong hysteresis behavior of PNIPA gels. A more diluted solution is required to make a swollen gel start to reshrink than to cause gel swelling. The results show strong attractive forces between the isopropyl groups of the PNIPA network and the DB groups of SDBS molecules. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1228–1232, 2002