One-Pot Aqueous Synthesis of Fe and Ag Core/Shell Nanoparticles

Carroll, Kyler J.; Hudgins, Daniel M.; Spurgeon, Steven R.; Kemner, Kennneth M.; Mishra, Bhoopesh; Boyanov, Maxim I.; Brown, L. W.; Taheri, Mitra L.; Carpenter, Everett E.

doi:10.1021/cm101996u

Cited by 74 publications

(64 citation statements)

References 56 publications

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“…24 Recently, there is increasing interest in the Fe/Ag core/shell nanoparticles possessing unusual magnetic and optical properties with potential applications. 25,26 The knowledge of the interfacial energy is important for the nanoparticle growth. In the present work, two types of Fe/Ag shape interface are considered, the Fe(001)/Ag(001) and the Fe(110)/Ag(111) interfaces.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of fcc-Ag/bcc-Fe interfaces

Punkkinen

et al. 2013

Phys. Rev. B

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Ab initio calculations are employed to determine the lower and upper bounds of the interfacial energy and work of separation of a fcc-Ag/bcc-Fe interface. The strain-free interfacial energy of the coherent interface is taken as the lower bound and the interfacial energy of the commensurate incoherent interface as the upper bound of the interfacial energy of a realistic semicoherent interface. The latter is estimated by applying an averaging scheme based on the interfacial energies obtained for the coherent interfaces. Similar calculations are performed for determining the bounds of the work of separation. We justify the use of the averaging scheme by carrying out large supercell calculations for a semicoherent interface. For a Fe(110)/Ag(111) semicoherent interface, we show that taking either Fe or Ag as the underlying lattice, our averaging scheme can yield a reasonable estimation of the work of separation of the semicoherent interface. However, when taking Ag as the underlying lattice, the averaged interfacial energy of the semicoherent interface is significantly underestimated due to the magnetism. The structure and magnetism at the coherent and semicoherent interfaces are discussed.

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Section: Introductionmentioning

confidence: 99%

First-principles study of fcc-Ag/bcc-Fe interfaces

Punkkinen

et al. 2013

Phys. Rev. B

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“…14 Chemical reduction of metal ions by sodium borohydrides has previously been used to prepare nanocrystalline magnetic materials, nanoalloys, and amorphous metals. 34,35 In this work, we report a new two-step synthesis to prepare magnetoresponsive gold/iron nanoparticles (Au/Fe NPs) with two mixed-ligand coatings, either mercaptopropionylsulfonic acid:-o c t a n e t h i o l ( M P S A : O T ) o r m e r c a p t o u n d e c y lsulfonate:octanethiol (MUS:OT). Structural characterization and elemental analysis demonstrate that the resulting bimetallic nanoparticles have an average diameter of 4 nm (MPSA:OT, 4.0 ± 1.3 nm; MUS:OT, 4.0 ± 1.0 nm) with an average atomic ratio of Au to Fe of 7 (MPSA:OT) and 8 (MUS:OT), which enables Au/Fe NPs to be superparamagnetic at room temperature, with a blocking temperature of 56 K (MPSA:OT) and 96 K (MUS:OT), depending on the coating.…”

Section: ■ Introductionmentioning

confidence: 99%

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T₂ Contrast Agent

et al. 2016

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Nanoparticle-based magnetic resonance imaging T 2 negative agents are of great interest, and much effort is devoted to increasing cellloading capability while maintaining low cytotoxicity. Herein, two classes of mixed-ligand protected magnetic-responsive, bimetallic gold/iron nanoparticles (Au/Fe NPs) synthesized by a two-step method are presented. Their structure, surface composition, and magnetic properties are characterized. The two classes of sulfonated Au/Fe NPs, with an average diameter of 4 nm, have an average atomic ratio of Au to Fe equal to 7 or 8, which enables the Au/Fe NPs to be superparamagnetic with a blocking temperature of 56 K and 96 K. Furthermore, preliminary cellular studies reveal that both Au/Fe NPs show very limited toxicity. MRI phantom experiments show that r 2 /r 1 ratio of Au/Fe NPs is as high as 670, leading to a 66% reduction in T 2 relaxation time. These nanoparticles provide great versatility and potential for nanoparticle-based diagnostics and therapeutic applications and as imaging contrast agents.

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“…5 It is possible to prevent oxidation of magnetic nanoparticles by employing a carbon or noble metal shell layer. 6,7 However, the synthesis of such oxide-free core/shell nanoparticles involve extremely flammable, toxic reagents that require special chambers and result in low reaction yields, making this process not practical for the fabrication of bulk composites. Aqueous sol-gel synthesis processes are safer and have higher yields for nanoparticle synthesis, 1, 8 but provide poor size control and the resulting magnetic nanoparticles are more prone to oxidation.…”

Section: Collectively Assembled Corona Magnetite Nanoparticlesmentioning

confidence: 99%

Multi-Ferroic Polymer Nanoparticle Composites for Next Generation Metamaterials

Kofinas

2014

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 05-11-20142. REPORT TYPE SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)AOARD UNIT 45002 APO AP 96338-5002 SPONSOR/MONITOR'S ACRONYM(S)AFRL/AFOSR/IOA(AOARD) SPONSOR/MONITOR'S REPORT NUMBER(S)AOARD-124013 DISTRIBUTION/AVAILABILITY STATEMENTDistribution Code A: Approved for public release, distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThe effort is a result of team work from the collaboration of Prof Kofinas (PI), Prof. Piao of Seoul National University, Korea and Prof. Begin-Colin of University of Strasbourg, France. It is desirable for a dielectric material of an RF antenna to have the highest possible permeability for the scaling factor, and lowest possible magnetic loss for the radiation efficiency. To reduce the dielectric loss, and achieve high permittivity and permeability at the frequency range of 1 MHz-1 GHz, the PI was able to assemble corona magnetite Nanoparticles successfully. The permeability values achieved by composites made from collectively assembled corona magnetite nanoparticles are significantly higher than the existing magnetite-polymer composites and magnetite-PDMS composites. Additionally, the composites prepared with collectively assembled corona magnetite nanoparticles exhibit an extraordinary magnetic resonance, which changes with the particle size of magnetite nanoparticles. The PI will continue to develop composites that could be utilized for developing highbandwidth radio frequency antennas. SUBJECT TERMS

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One-Pot Aqueous Synthesis of Fe and Ag Core/Shell Nanoparticles

Cited by 74 publications

References 56 publications

First-principles study of fcc-Ag/bcc-Fe interfaces

First-principles study of fcc-Ag/bcc-Fe interfaces

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T₂ Contrast Agent

Multi-Ferroic Polymer Nanoparticle Composites for Next Generation Metamaterials

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One-Pot Aqueous Synthesis of Fe and Ag Core/Shell Nanoparticles

Cited by 74 publications

References 56 publications

First-principles study of fcc-Ag/bcc-Fe interfaces

First-principles study of fcc-Ag/bcc-Fe interfaces

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T2 Contrast Agent

Multi-Ferroic Polymer Nanoparticle Composites for Next Generation Metamaterials

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Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T₂ Contrast Agent