TITLE:
Swelling Behavior of Polyacrylamide Hydrogels near Phase Transition
AUTHORS:
R. R. Janot Pacheco, M. E. S. R. Silva, R. G. Sousa, R. F. S. Freitas
KEYWORDS:
Polyacrylamide Hydrogels, Phase Transition, Swelling Behavior, Dynamic Correlation Length
JOURNAL NAME:
Materials Sciences and Applications,
Vol.5 No.8,
June
30,
2014
ABSTRACT: Hydrogels based on acrylamide (AA) and sodium methacrylate (NMA) as
ionic monomer were prepared by solution polymerization using
N,N’-methylenebis(acrylamide) (MBA) or ethylene glycol dimethacrylate (EGMA) as
crosslinkers and Ammonium Persulfate (APS) and N,N,N’,N’-Te-tramethyl-ethylenediamine
(TMEDA) as initiators. Swelling behavior was greatly affected by NMA content
near phase transition. Increasing ionic monomer concentration compared to total
monomer one led to high expansion in water, oscillating around 285 g/g for MBA
and 325 g/g for EGMA crosslinker, above 20% of NMA. Dynamic Light Scattering
experiments were performed and, for both crosslinkers, the dynamic correlation
length (ξ) decreased with increasing
NMA content, contributing to diminish hydrogels spatial inhomogeneities.