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Gamma-irradiation synthesis of poly(ethylene oxide)/iron oxide nanocomposite hydrogels

Simultaneous polymerization/crosslinking and reduction of metal salts using gamma-irradiation is a suitable method for preparing polymer nanocomposites with small nanoparticle size and narrow size distribution. In this work, the PEO/iron oxide nanocomposite hydrogels were synthesized by γ-irradiation of PEO/Fe(III)-salts in aqueous solutions. The molecular weights of PEO, concentration of PEO aqueous solution, type and concentration of Fe3+, pH, dose and other factors that influence the formation and properties of PEO nanocomposite hydrogels were investigated. The iron(III) chloride and iron(III) acetate salts were used as precursor for the synthesis of iron oxide nanoparticles inside PEO gel. The γ-irradiation of PEO/Fe3+ aqueous solutions produced hydrogels which were red to black in colours depending on iron concentration and applied dose. At ~120 kGy the PEO crosslinked into almost amorphous nanocomposite hydrogel. Hydrogels did not lose its consistency even at a large dose of γ-irradiation (up to 460 kGy). The scanning electron microscopy (SEM) showed the presence of nanoparticles precipitated in PEO matrix, while Mössbauer spectroscopy revealed the presence of goethite and Fe(III) in tetrahedral positions (Fig. 1). The role of γ-irradiation on the ability to precipitate and reduce the Fe3+ in the PEO structure and thus produce PEO/iron oxide nanocomposite hydrogels were discussed.

iron oxides ; nanoparticles ; PEO ; gamma-irradiation ; hydrogel ; suspension

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