Magnetite (Fe3O4) nanoparticles (NPs) modified with n-dodecylphosphonic acid (DDPA) were prepared by one-pot nonaqueous synthesis using a salt comprising tetrachloroferrate (III) anions and methyltrioctylammonium cations as an Fe source, n-octylamine as a reductant, pyridine-N-oxide as an oxygen donor and DDPA as a phosphorus coupling reagent. The X-ray diffraction patterns, X-ray photoelectron spectroscopy and high-resolution transmission electron microscope (HRTEM) observation showed the formation of Fe3O4 NPs when the amount of DDPA was small (DDPA/Fe < 1/16). Thermogravimetry and infrared spectroscopy demonstrated surface modification of Fe3O4 NPs with DDPA. TEM observation showed the size range of Fe3O4 NPs to be 2–10 nm. Dynamic light scattering analysis showed narrow particle size distribution of Fe3O4 NPs in toluene, moreover, with median diameters of 9.1 (DDPA1/32) and 16 nm (DDPA1/64). Magnetic characterization of Fe3O4 NPs modified with DDPA showed lower saturation magnetization as compared with unmodified Fe3O4 NPs, and indicated superparamagnetic Fe3O4 NPs formation.
|ジャーナル||Materials Research Bulletin|
|出版ステータス||Published - 2019 10月|
ASJC Scopus subject areas