Reversible Magnetic Agglomeration: A Mechanism for Thermodynamic Control over Nanoparticle Size.

Publisher: Wiley-VCH Country of Publication: Germany NLM ID: 0370543 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1521-3773 (Electronic) Linking ISSN: 14337851 NLM ISO Abbreviation: Angew Chem Int Ed Engl Subsets: PubMed not MEDLINE

Publication: <2004-> : Weinheim : Wiley-VCH
Original Publication: Weinheim/Bergstr. : New York, : Verlag Chemie ; Academic Press, c1962-

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.
(© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Keywords: magnetic agglomeration; nanoparticles; synthesis; thermodynamics; zero-valent iron

Date Created: 20180325 Latest Revision: 20191120

20250114

10.1002/anie.201800959

29573528