| Autor: |
Keng PY; Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA., Shim I, Korth BD, Douglas JF, Pyun J |
| Jazyk: |
angličtina |
| Zdroj: |
ACS nano [ACS Nano] 2007 Nov; Vol. 1 (4), pp. 279-92. |
| DOI: |
10.1021/nn7001213 |
| Abstrakt: |
We describe the synthesis and characterization of polymer-coated ferromagnetic cobalt nanoparticles (CoNPs). The synthesis of end-functionalized polystyrene surfactants possessing amine, carboxylic acid, or phosphine oxide end-groups was accomplished using atom-transfer radical polymerization. This versatile synthetic method enabled the production of multigram quantities of these polymeric surfactants that stabilized ferromagnetic CoNPs when dispersed in organic media. An in-depth investigation into the synthesis of polystyrene-coated ferromagnetic CoNPs was also conducted using various combinations of these polymeric surfactants in the thermolysis of dicobaltoctacarbonyl (Co(2)(CO)(8)). Moreover, the application of a dual-stage thermolysis with Co(2)(CO)(8) allowed for the preparation of large samples (200-820 mg) per batch of well-defined and dispersable ferromagnetic nanoparticles. Characterization of these functionalized nanoparticle materials was then done using transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry, and thermogravimetric analysis. Self-assembly of these dipolar nanoparticles was investigated in solutions cast onto supporting substrates, where local nematic-like ordering of nanoparticle chains was observed along with a tendency of adjacent chains to form "zippering" configurations, both phenomena having been predicted by recent simulations of dipolar fluids in conjunction with van der Waals interactions. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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