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Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process
[Image: see text] Magnetic nanoparticles are being developed as structural and functional materials for use in diverse areas, including biomedical applications. Here, we report the synthesis of maghemite (γ-Fe(2)O(3)) nanoparticles with distinct morphologies: single-core and multicore, including hol...
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2017
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6645291/ https://www.ncbi.nlm.nih.gov/pubmed/31457296 http://dx.doi.org/10.1021/acsomega.7b00975 |
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author | Gavilán, Helena Sánchez, Elena H. Brollo, María E. F. Asín, Laura Moerner, Kimmie K. Frandsen, Cathrine Lázaro, Francisco J. Serna, Carlos J. Veintemillas-Verdaguer, Sabino Morales, M. Puerto Gutiérrez, Lucía |
author_facet | Gavilán, Helena Sánchez, Elena H. Brollo, María E. F. Asín, Laura Moerner, Kimmie K. Frandsen, Cathrine Lázaro, Francisco J. Serna, Carlos J. Veintemillas-Verdaguer, Sabino Morales, M. Puerto Gutiérrez, Lucía |
author_sort | Gavilán, Helena |
collection | PubMed |
description | [Image: see text] Magnetic nanoparticles are being developed as structural and functional materials for use in diverse areas, including biomedical applications. Here, we report the synthesis of maghemite (γ-Fe(2)O(3)) nanoparticles with distinct morphologies: single-core and multicore, including hollow spheres and nanoflowers, prepared by the polyol process. We have used sodium acetate to control the nucleation and assembly process to obtain the different particle morphologies. Moreover, from samples obtained at different time steps during the synthesis, we have elucidated the formation mechanism of the nanoflowers: the initial phases of the reaction present a lepidocrocite (γ-FeOOH) structure, which suffers a fast dehydroxylation, transforming to an intermediate “undescribed” phase, possibly a partly dehydroxylated lepidocrocite, which after some incubation time evolves to maghemite nanoflowers. Once the nanoflowers have been formed, a crystallization process takes place, where the γ-Fe(2)O(3) crystallites within the nanoflowers grow in size (from ∼11 to 23 nm), but the particle size of the flower remains essentially unchanged (∼60 nm). Samples with different morphologies were coated with citric acid and their heating capacity in an alternating magnetic field was evaluated. We observe that nanoflowers with large cores (23 nm, controlled by annealing) densely packed (tuned by low NaAc concentration) offer 5 times enhanced heating capacity compared to that of the nanoflowers with smaller core sizes (15 nm), 4 times enhanced heating effect compared to that of the hollow spheres, and 1.5 times enhanced heating effect compared to that of single-core nanoparticles (36 nm) used in this work. |
format | Online Article Text |
id | pubmed-6645291 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-66452912019-08-27 Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process Gavilán, Helena Sánchez, Elena H. Brollo, María E. F. Asín, Laura Moerner, Kimmie K. Frandsen, Cathrine Lázaro, Francisco J. Serna, Carlos J. Veintemillas-Verdaguer, Sabino Morales, M. Puerto Gutiérrez, Lucía ACS Omega [Image: see text] Magnetic nanoparticles are being developed as structural and functional materials for use in diverse areas, including biomedical applications. Here, we report the synthesis of maghemite (γ-Fe(2)O(3)) nanoparticles with distinct morphologies: single-core and multicore, including hollow spheres and nanoflowers, prepared by the polyol process. We have used sodium acetate to control the nucleation and assembly process to obtain the different particle morphologies. Moreover, from samples obtained at different time steps during the synthesis, we have elucidated the formation mechanism of the nanoflowers: the initial phases of the reaction present a lepidocrocite (γ-FeOOH) structure, which suffers a fast dehydroxylation, transforming to an intermediate “undescribed” phase, possibly a partly dehydroxylated lepidocrocite, which after some incubation time evolves to maghemite nanoflowers. Once the nanoflowers have been formed, a crystallization process takes place, where the γ-Fe(2)O(3) crystallites within the nanoflowers grow in size (from ∼11 to 23 nm), but the particle size of the flower remains essentially unchanged (∼60 nm). Samples with different morphologies were coated with citric acid and their heating capacity in an alternating magnetic field was evaluated. We observe that nanoflowers with large cores (23 nm, controlled by annealing) densely packed (tuned by low NaAc concentration) offer 5 times enhanced heating capacity compared to that of the nanoflowers with smaller core sizes (15 nm), 4 times enhanced heating effect compared to that of the hollow spheres, and 1.5 times enhanced heating effect compared to that of single-core nanoparticles (36 nm) used in this work. American Chemical Society 2017-10-26 /pmc/articles/PMC6645291/ /pubmed/31457296 http://dx.doi.org/10.1021/acsomega.7b00975 Text en Copyright © 2017 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Gavilán, Helena Sánchez, Elena H. Brollo, María E. F. Asín, Laura Moerner, Kimmie K. Frandsen, Cathrine Lázaro, Francisco J. Serna, Carlos J. Veintemillas-Verdaguer, Sabino Morales, M. Puerto Gutiérrez, Lucía Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process |
title | Formation Mechanism of Maghemite Nanoflowers Synthesized
by a Polyol-Mediated Process |
title_full | Formation Mechanism of Maghemite Nanoflowers Synthesized
by a Polyol-Mediated Process |
title_fullStr | Formation Mechanism of Maghemite Nanoflowers Synthesized
by a Polyol-Mediated Process |
title_full_unstemmed | Formation Mechanism of Maghemite Nanoflowers Synthesized
by a Polyol-Mediated Process |
title_short | Formation Mechanism of Maghemite Nanoflowers Synthesized
by a Polyol-Mediated Process |
title_sort | formation mechanism of maghemite nanoflowers synthesized
by a polyol-mediated process |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6645291/ https://www.ncbi.nlm.nih.gov/pubmed/31457296 http://dx.doi.org/10.1021/acsomega.7b00975 |
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