Surface functionalization of magnetite nanoparticle: A new approach using condensation of alkoxysilanes

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Data

2017-09-01

Autores

Rodriguez, A. F. R.
Costa, T. P. [UNESP]
Bini, R. A. [UNESP]
Faria, F. S. E. D. V.
Azevedo, R. B.
Jafelicci, M. [UNESP]
Coaquira, J. A. H.
Martinez, M. A. R.
Mantilla, J. C.
Marques, R. F. C. [UNESP]

Título da Revista

ISSN da Revista

Título de Volume

Editor

Elsevier B.V.

Resumo

In this study we report on successful production of two samples (BR15 and BR16) comprising magnetite (Fe3O4) nanoparticles (similar to 10 nm) surface-functionalized via hydrolysis and condensation of alkoxysilane agents, namely 3-aminopropyl-trimethoxisilane (APTS) and N-propyl-trimethoxisilane (NPTS). The as-produced samples were characterized using transmission electron microscopy (TEM), x-ray diffraction (XRD), magnetization measurements (5 K and 300 K hysteresis cycles and zero field-cooled/field-cooled measurements), and Mossbauer spectroscopy (77 and 297 K). The Mossbauer data supported the model picture of a core-shell magnetite-based system. This material system shows shell properties influenced by the surface-coating design, either APTS-coated (BR15) or APTS+NPTS-coated (sample BR16). Analyses of the Mossbauer spectra indicates that the APTS-coated sample presents Fe(III)-rich core and Fe(II)-rich shell with strong hyperfine field; whereas, the APTS+NPTS-coated sample leads to a mixture of two main nanostructures, one essentially surface-terminated with APTS whereas the other surface-terminated with NPTS, both presenting weak hyperfine fields compared with the single surface-coated sample. Magnetization measurements support the core-shell picture built from the analyses of the Mossbauer data. Our findings emphasize the capability of the Mossbauer spectroscopy in assessing subtle differences in surface-functionalized iron-based core-shell nanostructures.

Descrição

Palavras-chave

Magnetite nanoparticles, Surface-functionalization, Hydrolysis and condensation reactions, X-ray diffraction, Mossbauer spectroscopy, Zero-field-cooled/field-cooled traces

Como citar

Physica B-condensed Matter. Amsterdam: Elsevier Science Bv, v. 521, p. 141-147, 2017.