A Mössbauer study of the chemical stability of iron oxide nanoparticles in PMMA and PVB beads

Wei Chen, Steen Mørup, Mikkel Fougt Hansen, T. Banert, U.A. Peuker

Research output: Contribution to journalJournal articleResearchpeer-review


We have prepared magnetic beads consisting of iron oxide nanoparticles in a polymethyl methacrylate (PMMA) and a polyvinyl butyral (PVB) matrix. High-field Mossbauer studies show that the particles have an almost perfect collinear spin structure and magnetization measurements show that they are superparamagnetic at room temperature at a time scale of seconds. We have followed the oxidation of the particles, which initially have a stoichiometry close to magnetite. The oxidation is fast during the first 2-3 weeks and then continues slowly such that even after 30 weeks the particles have not completely transformed to maghemite. The PVB beads are hydrophilic and biocompatible and are therefore well suited for applications in medicine and biology.
Original languageEnglish
JournalJournal of Magnetism and Magnetic Materials
Issue number16
Pages (from-to)2099-2105
Publication statusPublished - 2008


  • oxidation of Fe3O4
  • spray drying
  • magnetic bead
  • magnetic bio-separation
  • Mossbauer spectroscopy

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