Development of Multifunctional Magnetic Core Nanoparticles

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Hannula, Simo-Pekka, Prof., Aalto University, Department of Materials Science and Engineering, Finland Mahmed, Norsuria 2013-04-24T09:00:15Z 2013-04-24T09:00:15Z 2013
dc.identifier.isbn 978-952-60-5106-2 (electronic)
dc.identifier.isbn 978-952-60-5105-5 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.description.abstract Multifunctional magnetic materials have a great importance in various fields of application, e.g., material science, chemistry, physics, environmental chemistry and biomedicine. Although a large number of scientific papers already describe the synthesis of multifunctional materials by various methods and technologies, a simple, fast and economically feasible synthesis procedure to combine all the materials in one system is still of interest.  This thesis contributes to the development of multifunctional magnetic-core materials scientifically in three parts. Firstly, the synthesis of magnetic core, i.e., magnetite nanoparticles, was attempted using only ferrous ions (Fe2+) of various concentrations as a magnetite precursor under ambient atmosphere. It was found that the synthesized magnetite was in a non-stoichiometric state, i.e., oxidation occurs. The introduction of Stöber silica (SiO2) layer in the form of a coreshell structure prevented the oxidation of the synthesized particles, as suggested by the low temperature magnetic measurement and Mössbauer study. Secondly, this thesis introduces a simple, room temperature synthesis method for further functionalization of the magnetite-silica coreshell powders with silver (Ag) and silver/silver chloride (Ag/AgCl) nanoparticles. Based on the proposed approaches, the Ag deposition on the silica shells can take place by three possible mechanisms: a) absorption of Ag+ on the silica surface by ionic bonding between the silver ions and hydroxyl groups (OH) of silica followed by the reduction of Ag+ by polyvinylpyrrolidone (PVP), b) hydrogen bonding between the PVP-coated Ag and the SiO2 shells, and c) electrostatic attraction between PVP-coated Ag and SiO2 shells. The silver chloride particles are formed when a certain amount of hydrochloric acid (HCl) is introduced. The particle morphology is controlled by the concentration of HCl. Thirdly, the thesis makes a scientific contribution by introducing novel properties by compacting the magnetite-silica coreshell powders into bulk material by pulsed electric current sintering (PECS). By adjusting the amount of magnetite-core inside the silica structure, it is possible to produce a transparent magnetic compact. In addition, the effects of the sintering atmosphere and temperature on the final properties of the compacts were also studied.  en
dc.format.extent 114 + app. 81
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 58/2013
dc.relation.haspart [Publication 1]: Mahmed, N., Heczko, O., S.derberg, O. & Hannula, S-P (2011) Room temperature synthesis of magnetite (Fe3-δO4) nanoparticles by a simple reverse co-precipitation method. IOP Conference Series: Materials Science and Engineering, 18, 032020.
dc.relation.haspart [Publication 2]: Mahmed, N., Heczko, O., Lancok, A. & Hannula, S-P. The magnetic and oxidation behavior of bare and silica-coated iron oxide nanoparticles synthesized by reverse co-precipitation of ferrous ion (Fe2+) in ambient atmosphere. Submitted to Journal of Magnetism and Magnetic Materials.
dc.relation.haspart [Publication 3]: Mahmed, N., Jiang, H., Heczko, O., S.derberg, O. & Hannula, S-P (2012) Influence of different synthesis approach on doping behavior of silver nanoparticles onto the iron oxide-silica coreshell surfaces. Journal of Nanoparticle Research, 14, 987.
dc.relation.haspart [Publication 4]: Mahmed, N., Heczko, O. & Hannula, S-P (2013) Influence of hydrochloric acid concentrations on the formation of AgCl-doped iron oxide-silica coreshell structures. Advances in Science and Technology, 77, 184–189.
dc.relation.haspart [Publication 5]: Mahmed, N., Heczko, O., Maki, R., S.derberg, O., Haimi, E. & Hannula, SP (2012) Novel iron oxide-silica coreshell powders compacted by using pulsed electric current sintering: Optical and magnetic properties. Journal of the European Ceramic Society, 32, 2981–2988.
dc.relation.haspart [Publication 6]: Mahmed, N., Friman, M. & Hannula, S-P (2012) Phase transformation of iron oxide-silica coreshell structure during differential scanning calorimetry and pulsed electric current sintering processes: A comparison. Materials Letters, 85, 18–20.
dc.relation.haspart [Publication 7]: Mahmed, N., Larismaa, J., Heczko, O., Cura, M. E. & Hannula, S-P (2013) Influence of sintering temperature on the properties of pulsed electric current sintered hybrid coreshell powders. Journal of the European Ceramic Society.
dc.subject.other Materials science en
dc.title Development of Multifunctional Magnetic Core Nanoparticles en
dc.type G5 Artikkeliväitöskirja fi Kemian tekniikan korkeakoulu fi School of Chemical Technology en
dc.contributor.department Materiaalitekniikan laitos fi
dc.contributor.department Department of Materials Science and Engineering en
dc.subject.keyword magnetite en
dc.subject.keyword silica en
dc.subject.keyword silver en
dc.subject.keyword silver chloride en
dc.subject.keyword pulsed electric current sintering en
dc.subject.keyword phase transformation en
dc.subject.keyword multifunctional en
dc.subject.keyword ferromagnetic en
dc.identifier.urn URN:ISBN:978-952-60-5106-2
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Hannula, Simo-Pekka, Prof., Aalto University, Department of Materials Science and Engineering, Finland
dc.opn Leskelä, Markku, Prof., University of Helsinki, Finland
dc.contributor.lab Advanced and Functional Materials Group en
dc.rev Piccaluga, Giorgio, Prof., Universita di Cagliari, Italy
dc.rev del Puerto Morales, Maria, Dr., Instituto de Ciencia de Materiales de Madrid, Spain 2013-04-26

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