Sonochemical synthesis of functionalized amorphous iron oxide nanoparticles

Kurikka V.P.M. Shafi, Abraham Ulman, Xingzhong Yan, Nan Loh Yang, Claude Estournès, Henry White, Miriam Rafailovich

Research output: Contribution to journalArticlepeer-review


Sonochemical decomposition of Fe(CO)5 was carried out in the presence of different surfactants. The reactions give stable colloids of undecenoate, dodecyl sulfonate, and octyl phosphonate coated Fe2O3 nanoparticles of 5-16 nm in diameter. The ionic binding of the surfactants to the nanoparticle surfaces was confirmed by FTIR spectroscopy. Electron paramagnetic resonance measurements, magnetization curves, and zero-field cooled and field cooled studies indicate that the as-prepared amorphous nanoparticles are superparamagnetic. These studies show that the phosphonate-coated nanoparticles behave in a strikingly different manner from the other particles. It is proposed that the extra negative charge on the phosphonate, as compared to the carboxylate and sulfonate groups, makes it a strong bridging bidentate ligand, resulting in the formation of strong ionic bonds to the surface Fe3+ ions, which decreases the number of unpaired spins, possibly through a double superexchange mechanism through a Fe3+-O-P-O-Fe3+ pathway.

Original languageEnglish (US)
Pages (from-to)5093-5097
Number of pages5
Issue number16
StatePublished - Aug 7 2001

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry


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