MPc-Fe3O4-nanoparticles com posite （M=Co, Cu, Ni, Mn） have been prepared and the factors that influence their mean size have been studied. The mean size of the nanoparticles composite increase with the increase of complex temperature. The interaction of MPc with Fe3O4 nanoparticles has been studied. There are M-O covalent bonding and ionic bonding between MPc and Fe3O4 nanoparticles. The intensities of M-O bonding and ionic bonding are in vestigated. The complex mechanism of MPc with Fe3O4 nanoparticles have been studied. First, there are complex between MPc and all Fe3O4 nanoparticles. Then, Fe3O4 nanoparticles accumulate together to form the accumulators, MPc have the function of cohering Fe3O4 nanoparticles. A considerable number of MPc combine with Fe3O4 nanoparticles on the surface of the accumulators to form MPc-Fe3O4 nanoparticles composite. All the above proesses take place spontaneously. The structure model of MPc-Fe3O4 nanoparticles composite has also been investigated.
Magnetorheological suspension based on 20 (v/v) % CoPc-iron composite particles dispersed in sili-cone oil have been obtained, which exhibited dynamic shear stress up to 2000Pa upon application of external magnetic field at 1300 Oe. The response is faster than 0. 1s with superior reversibility of changes in viscosity induced by external magnetic field at above 12. 5℃. Further, it was found that the MR fluid is in possession of long-term stability a-eainst sedimentation.
GONG Rongzhou FANG Liang GUAN Jianguo YUAN Runzhang Wuhan University of Technology
Polyaniline-barium titanate （PAn-Ba-TiO3） ultrafine composite particles were prepared by the oxidative polymerization of aniline with H2O2 while barium titanate nanoparticles were synthesized with a sol-gel method. The infrared spectrogram shows that the polymerization of PAn in the hybrid process of PAn-BaTiO3 is similar with the polymeric process of pure aniline, and there is interaction of PAn and BaTiO3 in the PAn-Ba-TiO3. SEM and TEM results show that the average diameter of the composite particles is 1.50/m and the diameters of BaTiO3 nanoparticles are 5—15 nm in the composite particle. The electrical conductivity of the ultrafine composite particles is transformable from 100 to 1011S/cm by equilibrium doping or dedoping method using various concentration of HCl or NaOH solutions.
