Abstract: By using modified sol-gel method, BaTiO3 nano-films were coated on the surface of polyaniline particles. The structure and morphology of coated powders were characterized by TEM and FT-IR, the electrorheological effects were also investigated. The infrared spectrogram shows that there is N－O hydrogen-bond forming between PAn and BaTiO3 in coated particle. TEM results show that the diameters of the coated particles are 1.0～1.5 μm.In addition, the dielectric properties and electrorheological effects are improved greatly by the coating process. It has provided us a new method for the preparation of excellent ER materials and further studies should be continued.

Key words: Surface coating, PAn, BaTiO₃, Electrorheological effects, 　Dielectric properties