Colloidal Flower‐Shaped Iron Oxide Nanoparticles: Synthesis Strategies and Coatings |
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| Authors: | Helena Gavilán Anja Kowalski David Heinke Abhilash Sugunan Jens Sommertune Miriam Varón Lara K Bogart Oliver Posth Lunjie Zeng David González‐Alonso Christoph Balceris Jeppe Fock Erik Wetterskog Cathrine Frandsen Nicole Gehrke Cordula Grüttner Andrea Fornara Frank Ludwig Sabino Veintemillas‐Verdaguer Christer Johansson M Puerto Morales |
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| Affiliation: | 1. Department of Energy, Environment and Health, Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, Madrid, Spain;2. Micromod Partikeltechnologie GmbH, Rostock, Germany;3. NanoPET Pharma GmbH, Berlin, Germany;4. The Swedish Research Institute, Stockholm, Sweden;5. Department of Physics, Technical University of Denmark, Fysikvej, Kongens Lyngby, Denmark;6. Healthcare Biomagnetics Laboratory, University College of London, London, UK;7. Physikalisch‐Technische Bundesanstalt, Berlin, Germany;8. Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden;9. Department of CITIMAC, University of Cantabria, Santander, Spain;10. Institute of Electrical Measurement and Fundamental Electrical Engineering, Braunschweig, Germany;11. Department of Micro‐ and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark;12. Department of Engineering Sciences, ?ngstr?m Laboratory, Uppsala University, Uppsala, Sweden;13. Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, Madrid, Spain;14. RISE Acreo, G?teborg, Sweden |
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| Abstract: | The assembly of magnetic cores into regular structures may notably influence the properties displayed by a magnetic colloid. Here, key synthesis parameters driving the self‐assembly process capable of organizing colloidal magnetic cores into highly regular and reproducible multi‐core nanoparticles are determined. In addition, a self‐consistent picture that explains the collective magnetic properties exhibited by these complex assemblies is achieved through structural, colloidal, and magnetic means. For this purpose, different strategies to obtain flower‐shaped iron oxide assemblies in the size range 25–100 nm are examined. The routes are based on the partial oxidation of Fe(OH)2, polyol‐mediated synthesis or the reduction of iron acetylacetonate. The nanoparticles are functionalized either with dextran, citric acid, or alternatively embedded in polystyrene and their long‐term stability is assessed. The core size is measured, calculated, and modeled using both structural and magnetic means, while the Debye model and multi‐core extended model are used to study interparticle interactions. This is the first step toward standardized protocols of synthesis and characterization of flower‐shaped nanoparticles. |
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| Keywords: | colloids magnetic properties magnetite nanoflowers self‐assembly |
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