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Determining the scaling of gel mesh size with changing crosslinker concentration using dynamic swelling, rheometry, and PGSE NMR spectroscopy
Author(s) -
Wisniewska Malgorzata Anna,
Seland John Georg,
Wang Wei
Publication year - 2018
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.46695
Subject(s) - rheometry , swelling , diffusion , self healing hydrogels , materials science , scaling , rheology , polymer chemistry , analytical chemistry (journal) , chemical engineering , composite material , chemistry , chromatography , thermodynamics , physics , mathematics , geometry , engineering
We studied the scaling behavior of the mesh size ( ξ ) of chemically crosslinked poly( N ‐isopropylacrylamide‐ co ‐acrylic acid) hydrogels with changing crosslinker concentration ( C cl ) from 0.006 to 0.143 mol L −1 . Three experimental methods were employed, namely dynamic swelling, rheometry, and probe diffusion by pulsed gradient spin‐echo NMR. The mesh sizes determined by probe diffusion are dependent on the probe size. The scaling model of ξ ∼( C cl) n( n < 0) could describe variation of the mesh size, obtained by any of the aforementioned techniques, with the crosslinker concentration. Thus, for hydrogels in equilibrium with water, the obtained values of the scaling exponent ( n ) are −0.73 ± 0.05 for dynamic swelling, −1.0 ± 0.3 for probe diffusion, and −0.27 ± 0.02 for rheological measurements. We demonstrated that the scaling of the mesh sizes for probe diffusion and dynamic swelling results was in good agreement with theoretical prediction. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46695.