Nano Archive

No aging phenomena in ferrofluids: The influence of coating on interparticle interactions of maghemite nanoparticles

Rabias, Ioannis and Fardis, Michael and Devlin, Eamonn and Boukos, Nikos and Tsitrouli, Danai and Papavassiliou, George (2008) No aging phenomena in ferrofluids: The influence of coating on interparticle interactions of maghemite nanoparticles. ACS NANO, 2 (5). pp. 977-983.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/nn700414w

Abstract

The influence of coating on interparticle interactions in ferrofluids has been investigated using various techniques such as Mossbauer spectroscopy, magnetometry, transmission electron microscopy, photon correlation spectroscopy, X-ray diffraction, X-ray photoelectron, and resonance micro-Raman spectroscopy. Aging and spin-glass-like behavior was investigated in frozen ferrofluids of various concentrations from dense, initial value of 40 mg of coated nanoparticles per 1 mL of water, to dilute 1:10 (4 mg/mL). The as-prepared nanoparticles, core size 7-8 nm, were subsequently coated with a gummic acid corona of 20 nm thickness, which was observed to prevent agglomeration and to delay aggregation even in dense ferrofluids. The resulting separation of magnetic cores due to the coating eliminated all magnetic interparticle interaction mechanisms, such as exchange and dipole-dipole, thus ensuring no aging effects of the magnetic particle system, as manifested in particle agglomeration and precipitation.

Item Type:Article
Uncontrolled Keywords:no aging phenomena; interparticle interactions; ferrofluids; gummic acid; maghemite nanoparticles
Subjects:Physical Science > Nanomagnetics
Material Science > Nanostructured materials
ID Code:1877
Deposited By:Farnush Anwar
Deposited On:16 Dec 2008 11:47
Last Modified:16 Dec 2008 11:47

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