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Towards 3‐D Spherical Self‐Assembly by Ternary Surfactant Combinations: The Case of Magnetite Nanoparticles
Author(s) -
Hou Yanglong,
Gao Song,
Ohta Toshiaki,
Kondoh Hiroshi
Publication year - 2004
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200300779
Subject(s) - magnetite , ternary operation , superparamagnetism , chemistry , x ray photoelectron spectroscopy , fourier transform infrared spectroscopy , nanoparticle , transmission electron microscopy , chemical engineering , magnetic nanoparticles , analytical chemistry (journal) , pulmonary surfactant , scanning electron microscope , materials science , organic chemistry , magnetization , composite material , metallurgy , biochemistry , physics , quantum mechanics , computer science , magnetic field , engineering , programming language
Here we report on a facile one‐step route to assemble magnetite nanoparticles into 3D‐spherical aggregates with an average diameter of 100 nm. The self‐assembly approach was achieved in a solvothermal reduction reaction with a ternary surfactant combination comprising trioctylphosphane oxide (TOPO), polyvinylpyrrolidone (PVP), and oleic acid as the “mortar”. Transmission electron microscopy (TEM) investigations indicated that the spherical aggregates were composed of magnetite nanoparticles. The mean size of the individual magnetite particles was estimated to be 6 nm, calculated by the Scherrer equation with the powder X‐ray diffraction (XRD) data. The formation mechanism of magnetite spheres can be attributed to the cooperation of the ternary surfactants described above. Magnetic measurements performed by a Quantum Design SQUID magnetometer on the nanoparticles exhibited superparamagnetic behavior above liquid‐nitrogen temperatures. Fourier‐transform infrared spectroscopy (FTIR), inductively coupled plasma‐atomic emission spectrometer (ICP‐AE) and X‐ray photoelectron spectroscopy (XPS) were also used in the characterization of the assembled magnetite spheres. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)