Colloidal iron dispersions prepared via the polymer-catalyzed decomposition of iron pentacarbonyl

Smith, Thomas W.; Wychick, Darlene

doi:10.1021/j100449a037

Cited by 186 publications

(114 citation statements)

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“…The magnetic fluids find uses in data storage media, magnetic refrigeration, audio reproduction and magnetic sealing 10,11 .Most commercial magnetic fluids are generally produced by grinding of magnetite (Fe 3 O 4 ) in ball wills for several days in the presence of surfactants, which produces a broad particle size distribution 12 . Chemical methods such as thermolysis of organometallic compounds and metal evaporation have also been applied to produce colloids of ferromagnetic materials 13,14 .…”

Section: Introductionmentioning

confidence: 99%

Iron Colloids Prepared by Chemical Liquid Deposition

G¹

2010

J. Chil. Chem. Soc.

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Iron colloids were prepared by cocondensation of the metal at 77K with ethanol, 2-propanol and 2-methoxyethanol. The distribution of particle sizes was determined by transmission electron microscopy.The particle size of the colloidal dispersions ranges from 3.94 nm for Fe-ethanol and 6.70 nm for Fe-methoxyethanol. Electron diffraction was carried out for Fe-2-propanol colloids and exhibit the presence of FeO.Electrophoretic measurements such as colloid charge and zeta potential were achieved. lt was found that the colloids possess electrical charge, therefore it is postulated that their stability is by simple solvatation. The colloids showed very high stability at room temperature, being over 30 days.In some colloids absorption bands in the UV region were observed. A band at 201 nm and the band at 320 nm is due to the absorption of metal-metal. In the visible region no plasma absorption was found.

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Section: Introductionmentioning

confidence: 99%

Iron Colloids Prepared by Chemical Liquid Deposition

G¹

2010

J. Chil. Chem. Soc.

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“…As a result, a desirable morphology can be obtained by the control of the copolymer composition, the volume fraction of NPs, and so forth. 5,18,28 In particular, in the case of hybrids involving ferromagnetic NPs such as iron 29 and cobalt, 30 the strong magnetic interactions among NPs can cause clustering or extensive aggregation 31,32 because block copolymers are often weakly associated with NPs. Consequently, for the microphaseseparated block copolymers, the addition of strongly interacting magnetic NPs can change the characteristic dimensions or even the morphology of the ordered copolymer structures.…”

Section: Introductionmentioning

confidence: 99%

Effect of interacting nanoparticles on the ordered morphology of block copolymer/nanoparticle mixtures

Park

Hyeon

et al. 2006

J Polym Sci B Polym Phys

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ABSTRACT:We investigated the effect of hard additives, that is, magnetic nanoparticles (NPs) and metal NPs, on the ordered morphology of block copolymers by varying the NP concentration. To characterize the structural changes of a block copolymer associated with different NP loadings, small-angle X-ray scattering and transmission electron microscopy were performed. Monodisperse maghemite (c-Fe 2 O 3 ) NPs (7 nm in diameter) and silver (Ag) NPs (6 nm in diameter) with surfaces modified with oleic acids were synthesized, and a cylinder-forming poly(styrene-block-isoprene) diblock copolymer was used as a structure-directing matrix for the NPs. As the NP concentration increased, domains of NP aggregates were observed for both magnetic and metal NPs. In the case of mixtures of cylinder-forming poly(styrene-block-isoprene) and Ag NPs with weak particle-particle interactions, random aggregates of Ag NPs were observed, and the ordered morphology of the block copolymer lost its long-range order with an increase in the NP concentration. However, regular, latticelike aggregates obtained with c-Fe 2 O 3 NPs, because of the strong interparticle interactions, induced an intriguing morphological transformation from hexagonal cylinders to body-centered-cubic spheres via undulated cylinders, whereas the neat block copolymer did not show such a morphological transition over a wide range of temperatures. The interplay between magnetic NPs and the block copolymer was also tested with magnetic NPs of different sizes.

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“…[1][2][3][4][5][6][7] Iron oxide nanocrystals in the magnetic form of maghemite have also been used as the precursor catalyst for chemical vapor deposition growth of carbon nanotubes, and it is generally believed that the diameter of the tubes is determined by the size of catalyst particles. 2,3 Various chemical syntheses have been used to fabricate magnetic nanocrystals, [5][6][7][8] among which, ␥-Fe 2 O 3 nanocrystals were synthesized by thermal decomposition of iron pentacarbonyl in the presence of surfactants (also referred to here as ligands), 7 which bind to the surface of the nanocrystals and give rise to a steric barrier to aggregation. This method has widely been used because of the ease and reproducibility of the synthesis, as well as the uniformity, high crystallinity, and monodispersity of the product.…”

Section: Introductionmentioning

confidence: 99%

Influence of Capping Groups on the Synthesis of γ-Fe₂O₃ Nanocrystals

et al. 2004

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Monodisperse and uniform ␥-Fe 2 O 3 (maghemite) nanocrystals of variable size were prepared by thermal decomposition of iron pentacarbonyl [Fe(CO) 5 ] in the presence of surfactants, following controlled oxidation with trimethylamine N-oxide as a mild oxidant. The influence of carboxylic acids with variable alkyl carbon chain lengths on the synthesis of ␥-Fe 2 O 3 nanocrystals was investigated. The effect of the molar ratios of surfactant to iron precursor was also studied. The nanocrystals were characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD showed the particles were highly crystalline at the nanometer scale. The results showed that the size and shape of the nanocrystal is strongly influenced by the decomposition temperature of iron pentacarbonyl and closely related to the length of carbon chain of the capping groups and the molar ratio of surfactant to iron precursor. Following controlled evaporation from nonpolar solvents, self-assembly into two-dimensional arrays could be observed by TEM. It was also found that the distance between the nanocrystals in self-assembled structures matched the length of the capping molecules very well.

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Colloidal iron dispersions prepared via the polymer-catalyzed decomposition of iron pentacarbonyl

Cited by 186 publications

References 4 publications

Iron Colloids Prepared by Chemical Liquid Deposition

Iron Colloids Prepared by Chemical Liquid Deposition

Effect of interacting nanoparticles on the ordered morphology of block copolymer/nanoparticle mixtures

Influence of Capping Groups on the Synthesis of γ-Fe₂O₃ Nanocrystals

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Colloidal iron dispersions prepared via the polymer-catalyzed decomposition of iron pentacarbonyl

Cited by 186 publications

References 4 publications

Iron Colloids Prepared by Chemical Liquid Deposition

Iron Colloids Prepared by Chemical Liquid Deposition

Effect of interacting nanoparticles on the ordered morphology of block copolymer/nanoparticle mixtures

Influence of Capping Groups on the Synthesis of γ-Fe2O3 Nanocrystals

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Influence of Capping Groups on the Synthesis of γ-Fe₂O₃ Nanocrystals