The evolution of the particle shape distribution during the formation of iron nanoparticles in the presence of tubular lecithin assemblies

Abstract

Iron particles were prepared by the sodium borohydride reduction of ferrous ion in tubular lecithin assemblies and a 1200 e magnetic f i e l d .When the reaction was quenched after two minutes more than 90% of the particles were acicular, s i n g l e crystal iron.As the reaction proceeded the percentage of acicular particles decreased, w h i l e spherical and chains-of-sphere particles were formed.After 30 minutes the predominant particle shape was chains-of-spheres. This change i n particle shape distribution was attributed to the ~r e a k -~p of the lecithin assemblies during the course of the reduction.

Sonochemistry under an Applied Magnetic Field: Determining the Shape of a Magnetic Particle

“…They obtained acicular iron particles that contained, however, spherical particles and chains of spherical particles as well. In a later publication they embedded the ferrous ions in tabular lecithin assemblies and carried out the reduction in a magnetic field of 1.2 kG. The aliquots removed after 2 min contained more than 90% acicular iron particles.…”

The use of organic templates to develop biomimetic chain structures of magnetic nanoparticles

“…Magnetic iron nanoparticles have been synthesized in AOT/water/isooctane microemulsions and tubular lecithin assemblies. 3,4,5 These nanoparticles form under the templating environment via the reduction of metal cations. They are typically spherical or acicular particles.…”

Synthesis and Magnetic Properties of Single‐Crystals of MnFe2O4 Nanorods

“…[9] Acicular iron particles were prepared by reduction of ferrous ions with sodium borohydride in tubular lecithin. [10] The substance MnFe 2 O 4 , one of the most important magnetic materials, has been widely used in electronic applications [11,12] and contrast-enhancement agents in magnetic resonance imaging (MRI) technology, [13Ϫ16] in addition to recording media. Several techniques have been developed to synthesize MnFe 2 O 4 nanoparticles, such as solid-phase reactions, [17] mechanical ball-milling, [18,19] thermal decomposition, [20] and coprecipitation methods.…”