Synthes is and self-assembly of polymer-coated ferromagnetic nanoparticles

被引:138
作者
Keng, Pei Yuin [1 ]
Shim, Inbo [1 ,2 ]
Korth, Bryan D. [1 ]
Douglas, Jack F. [3 ]
Pyun, Jeffrey [1 ]
机构
[1] Univ Arizona, Dept Chem, Tucson, AZ 85721 USA
[2] Kookmin Univ, Dept Nano & Elect Phys, Seoul 136702, South Korea
[3] NIST, Div Polymers, Gaithersburg, MD 20899 USA
关键词
magnetic nanoparticles; magnetic nanocomposites; nanoparticle assembly; self-assembly; equilibrium polymerization; ring formation; polymer stabilization; particle synthesis; particle characterization;
D O I
10.1021/nn7001213
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
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.
引用
收藏
页码:279 / 292
页数:14
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