Monodispersed core-shell Fe3O4@Au nanoparticles.
The ability to synthesize and assemble monodispersed core-shell nanoparticles is important for exploring the unique properties of nanoscale core, shell, or their combinations in technological applications. This paper describes findings of an investigation of the synthesis and assembly of core (Fe(3)O(4))-shell (Au) nanoparticles with high monodispersity. Fe(3)O(4) nanoparticles of selected sizes were used as seeding materials for the reduction of gold precursors to produce gold-coated Fe(3)O(4) nanoparticles (Fe(3)O(4)@Au). Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, core-shell composition, surface reactivity, and magnetic properties have confirmed the formation of the core-shell nanostructure. The interfacial reactivity of a combination of ligand-exchanging and interparticle cross-linking was exploited for molecularly mediated thin film assembly of the core-shell nanoparticles. The SQUID data reveal a decrease in magnetization and blocking temperature and an increase in coercivity for Fe(3)O(4)@Au, reflecting the decreased coupling of the magnetic moments as a result of the increased interparticle spacing by both gold and capping shells. Implications of the findings to the design of interfacial reactivities via core-shell nanocomposites for magnetic, catalytic, and biological applications are also briefly discussed.
Wang
Lingyan
L
Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, USA.
Luo
Jin
J
Fan
Quan
Q
Suzuki
Masatsugu
M
Suzuki
Itsuko S
IS
Engelhard
Mark H
MH
Lin
Yuehe
Y
Kim
Nam
N
Wang
Jian Q
JQ
Zhong
Chuan-Jian
CJ
D005290:Ferric Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
D005290:Ferric Compounds; C000499:ferric oxide; D006046:Gold