Reversible Magnetic Agglomeration: A Mechanism for Thermodynamic Control over Nanoparticle Size
- Sandia National Laboratories Albuquerque NM 87111 USA
- Department of Chemistry San Jose State University San Jose CA 95192 USA
Abstract We present a method for the synthesis and precise size control of magnetic nanoparticles in a reversible magnetic agglomeration mechanism. In this approach, nanoparticles nucleate and grow until a critical susceptibility is reached, in which magnetic attraction overcomes dispersive forces, leading to agglomeration and precipitation. This phase change in the system arrests nanoparticle growth and gives true thermodynamic control over the size of nanoparticles. We then show that increasing the alkyl chain length of the surfactant, and hence increasing steric stabilization, allows nanoparticles to grow to larger sizes before agglomeration occurs. Therefore, simply by choosing the correct surfactant, the size and magnetic properties of iron nanoparticles can be tailored for a particular application. With the continuous addition of the precursor solution, we can repeat the steps of nucleation, growth, and magnetic agglomeration indefinitely, making the approach suitable for large scale syntheses.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1434809
- Journal Information:
- Angewandte Chemie (International Edition), Journal Name: Angewandte Chemie (International Edition) Vol. 57 Journal Issue: 26; ISSN 1433-7851
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
Web of Science
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