Structural and vibrational studies of fatty acids-functionalized iron oxide nanoparticles via alkaline co-precipitation route

W. T. Herrera, Juan Adrian Ramos Guivar, J. C. González, E. M. Baggio-Saitovitch

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

The preparation and functionalization of iron oxide magnetic nanoparticles (MNPs) are of great importance in a diverse range of applications. However, their structural and magnetic properties can be influenced by the process of coating making these MNPs undesirable for certain applications. For that reason, this work is focused in the understanding of iron oxide nanoparticles functionalized with fatty functional lauric acid (LA) and oleic acid (OA) organic molecules. The synthesis was carried out using the aqueous alkaline co-precipitation route of Fe+2 and Fe3+ salts. The characterization was done by several spectroscopy techniques. X-Ray Diffraction (XRD) measurements reveal uncoated iron oxide nanoparticles with mean diameter of 11.8 ± 2 nm obtained from Debye-Sherrer formula. The spinel crystal structure and lattice parameter was found to be 8.38 ± 0.01 Å which means that the stoichiometric structure is not affected by the functionalization process. This size decreased at around 9.7 ± 2 and 8.6 ± 2 nm for coated with OA and LA which are in agreement with Transmission Electron Microscopy (TEM) measurements. X-ray Photoelectron Spectroscopy (XPS) measurements determined that iron atoms have valences of +3 and +2, with a total ratio of iron atoms Fe+3: Fe+2 of 2:1 which confirmed the stoichiometric relation used for magnetite (Fe3O4). Fourier Transform Infrared Spectroscopy (FTIR) measurements show that LA and OA molecules are chemisorbed onto MNPs surface ascribed to bridging bidentate interaction. The thermal stability of the functional groups anchored to magnetite surface was studied by thermogravimetric analysis (TGA) at certain range of temperatures. From TGA measurements we calculate the number of functionalized molecules anchored to the surface of Fe3O4 nanoparticles. Micro-Raman spectroscopy was introduced to study the stabilization of organic molecules on MNPs surface.

Original languageEnglish
Title of host publicationNANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings
PublisherTANGER Ltd.
Pages511-519
Number of pages9
ISBN (Electronic)9788087294635
StatePublished - 2015
Externally publishedYes
Event7th International Conference on Nanomaterials - Research and Application, NANOCON 2015 - Brno, Czech Republic
Duration: 14 Oct 201516 Oct 2015

Publication series

NameNANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings

Conference

Conference7th International Conference on Nanomaterials - Research and Application, NANOCON 2015
CountryCzech Republic
CityBrno
Period14/10/1516/10/15

Bibliographical note

Funding Information:
This work was supported by a grant (No. 013-2013) from the National Council of Science, Technology and Technological Innovation (CONCYTEC/FONDECYT-Peru). Ramos Guivar Juan A. is also grateful to FONDECYT (Grant No. 0218-2014).

Keywords

  • Co-precipitation route
  • Fatty acids
  • Iron oxide nanoparticles
  • Magnetite

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