Superparamagnetic carbon-coated Fe3O4 nanoparticles with high magnetization（85 emu·g-（-1）） and high crystallinity were synthesized using polyethylene glycol-4000（PEG（4000）） as a carbon source.Fe3O4 water-...Superparamagnetic carbon-coated Fe3O4 nanoparticles with high magnetization（85 emu·g-（-1）） and high crystallinity were synthesized using polyethylene glycol-4000（PEG（4000）） as a carbon source.Fe3O4 water-based bilayer-surfactant-enveloped ferrofluids were subsequently prepared using sodium oleate and PEG（4000） as dispersants.Analyses using X-ray photoelectron spectroscopy,X-ray diffraction,and Fourier-transform infrared spectroscopy indicate that the Fe3O4 nanoparticles with a bilayer surfactant coating retain the inverse spinel-type structure and are successfully coated with sodium oleate and PEG（4000）.Transmission electron microscopy,vibrating sample magnetometry,and particle-size analysis results indicate that the coated Fe3O4 nanoparticles also retain the good saturation magnetization of Fe3O4（79.6 emu·g^-1） and that the particle size of the bilayer-surfactant-enveloped Fe3O4 nanoparticles is 42.97 nm,which is substantially smaller than that of the unmodified Fe3O4 nanoparticles（486.2 nm）.UV-vis and zeta-potential analyses reveal that the ferrofluids does not agglomerate for 120 h at a concentration of 4 g·L^-1,which indicates that the ferrofluids are highly stable.展开更多
基金supported by the National Natural Science Foundation of China (No.51063003)the Ministry of Science and Technology Project (No.2009GJG10041)the Fundamental Research Funds for the Universities of Gansu (No.1105ZTC136)
文摘Superparamagnetic carbon-coated Fe3O4 nanoparticles with high magnetization（85 emu·g-（-1）） and high crystallinity were synthesized using polyethylene glycol-4000（PEG（4000）） as a carbon source.Fe3O4 water-based bilayer-surfactant-enveloped ferrofluids were subsequently prepared using sodium oleate and PEG（4000） as dispersants.Analyses using X-ray photoelectron spectroscopy,X-ray diffraction,and Fourier-transform infrared spectroscopy indicate that the Fe3O4 nanoparticles with a bilayer surfactant coating retain the inverse spinel-type structure and are successfully coated with sodium oleate and PEG（4000）.Transmission electron microscopy,vibrating sample magnetometry,and particle-size analysis results indicate that the coated Fe3O4 nanoparticles also retain the good saturation magnetization of Fe3O4（79.6 emu·g^-1） and that the particle size of the bilayer-surfactant-enveloped Fe3O4 nanoparticles is 42.97 nm,which is substantially smaller than that of the unmodified Fe3O4 nanoparticles（486.2 nm）.UV-vis and zeta-potential analyses reveal that the ferrofluids does not agglomerate for 120 h at a concentration of 4 g·L^-1,which indicates that the ferrofluids are highly stable.
