Influence of the initiator system on the spatial inhomogeneity in acrylamide-based hydrogels

Orakdogen N., Okay O.

JOURNAL OF APPLIED POLYMER SCIENCE, vol.103, no.5, pp.3228-3237, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 103 Issue: 5
  • Publication Date: 2007
  • Doi Number: 10.1002/app.24977
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3228-3237
  • Istanbul Technical University Affiliated: Yes


The effect of the initiator system used in the gel preparation on the spatial inhomogeneity in poly(acrylamide) (PAAm) and poly(N,N-dimethylacrylamide) (PDMA) hydrogels was investigated by static light scattering and elasticity measurements. The hydrogels were prepared by free-radical crosslinking copolymerization of the monomers acrylamide (AAm) or N,N-dimethylacrylamide (DMA) with N,N'-methylenebisacrylamide as a crosslinker. Two different redox-initiator systems, ammonium persulfate (APS)N,N,N',N'-tetramethylethylenediamine (TEMED) and APS-sodium metabisulfite (SPS), were used to initiate the gelation reactions. Compared to the APS-TEMED redox pair, no significant scattered light intensity rise was observed during the crosslinking polymerization reactions initiated by the APS-SPS system. It was found that both PAAm and PDMA gels are much more homogeneous when the APS-SPS redox pair was used as the initiator. The results are explained by the formation of shorter primary chains as well as the delay of the gel point in APS-SPS initiated gel formation reactions. (c) 2006 Wiley Periodicals, Inc.