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Templated growth of superparamagnetic iron oxide nanoparticles by temperature programming in the presence of poly(vinyl alcohol)

Mahmoudi, M ; Sharif University of Technology | 2010

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  1. Type of Document: Article
  2. DOI: 10.1016/j.tsf.2009.12.112
  3. Publisher: 2010
  4. Abstract:
  5. Magnetite (Fe3O4) nanostructures with different morphologies including uniform nanoparticles, magnetic beads and nanorods were synthesized via a co-precipitation method. The synthesis process was performed at various temperatures in the presence of polyvinyl alcohol (PVA) at different concentrations. It is shown that small amounts of PVA act as a template in hot water (70 °C), leading to the oriented growth of Fe3O4 nanorods, which was confirmed by selected area electron diffraction. Individually coated magnetite nanoparticles and magnetic beads were formed at a relatively lower temperature of 30 °C in the folded polymer molecules due to the thermo-physical properties of PVA. When a moderate temperature (i.e. 50 °C) was used, nanorods and nanobeads co-existed. At higher concentrations of PVA (polymer/iron mass ratio of 5), however, the formation of magnetic beads was favored. The nanorods were shown to be unstable upon exposure to electron beams. Freezing/thawing process was applied post synthesis as temperature programming to fabricate stable nanorods with rigid walls
  6. Keywords:
  7. Freezing/thawing process ; Iron oxide ; Magnetic properties ; Nanoparticle ; Nanorods ; Poly(vinyl alcohol) ; Transmission electron microscopy ; Coprecipitation method ; Freezing/thawing process ; Hot water ; Magnetic beads ; Magnetite nanoparticles ; Mass ratio ; Moderate temperature ; Nanobeads ; Oriented growth ; Polymer molecule ; Postsynthesis ; Rigid wall ; Selected area electron diffraction ; Superparamagnetic iron oxide nanoparticles ; Synthesis process ; Temperature-programming ; Templated growth ; Thermo-physical property ; Electron beams ; Electrons ; Iron oxides ; Magnetic materials ; Magnetic properties ; Magnetite ; Nanomagnetics ; Nanoparticles ; Oxide minerals ; Precipitation (chemical) ; Scanning electron microscopy ; Superparamagnetism ; Transmission electron microscopy ; Water ; Nanorods
  8. Source: Thin Solid Films ; Volume 518, Issue 15 , 2010 , Pages 4281-4289 ; 00406090 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0040609010000374