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Size and property bimodality in magnetic nanoparticle dispersions : single domain particles vs. strongly coupled nanoclusters

Wetterskog, E.; Castro, A. LU ; Zeng, L.; Petronis, S.; Heinke, D.; Olsson, E.; Nilsson, Lars LU ; Gehrke, N. and Svedlindh, P (2017) In Nanoscale 9(12). p.4227-4235
Abstract

The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic,... (More)

The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic, and magnetic resonance properties. Finally, we show how the FMR spectra are influenced by dynamical effects; agglomeration of the superparamagnetic fraction leads to reversible line-broadening; rotational alignment of the suspended nanoclusters results in shape-dependent resonance shifts. The AF4 and FMR measurements described herein are fast and simple, and therefore suitable for quality control procedures in commercial production of magnetic nanoparticles.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nanoscale
volume
9
issue
12
pages
9 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85016118237
  • wos:000397966400022
ISSN
2040-3364
DOI
10.1039/c7nr00023e
language
English
LU publication?
yes
id
da634d53-bf49-4e1c-a30c-a068aa0f3a68
date added to LUP
2017-04-05 08:37:49
date last changed
2018-03-11 04:38:52
@article{da634d53-bf49-4e1c-a30c-a068aa0f3a68,
  abstract     = {<p>The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic, and magnetic resonance properties. Finally, we show how the FMR spectra are influenced by dynamical effects; agglomeration of the superparamagnetic fraction leads to reversible line-broadening; rotational alignment of the suspended nanoclusters results in shape-dependent resonance shifts. The AF4 and FMR measurements described herein are fast and simple, and therefore suitable for quality control procedures in commercial production of magnetic nanoparticles.</p>},
  author       = {Wetterskog, E. and Castro, A. and Zeng, L. and Petronis, S. and Heinke, D. and Olsson, E. and Nilsson, Lars and Gehrke, N. and Svedlindh, P},
  issn         = {2040-3364},
  language     = {eng},
  month        = {03},
  number       = {12},
  pages        = {4227--4235},
  publisher    = {Royal Society of Chemistry},
  series       = {Nanoscale},
  title        = {Size and property bimodality in magnetic nanoparticle dispersions : single domain particles vs. strongly coupled nanoclusters},
  url          = {http://dx.doi.org/10.1039/c7nr00023e},
  volume       = {9},
  year         = {2017},
}