Characterization and Electrorheological Effect of H2SO4-modified TiO2 Particles

H2SO4-modified TiO2 particles were prepared using a sol-gel method followed by impregnating the dry gels with sulphuric acid and were used to fabricate an electrorheological (ER) fluid with high ER activity. The as-synthesized H2SO4-modified TiO2 paritcles were characterized by fourier transform infrared dielectric spectra of the ER fluids were measured. The results show that H2SO4-modified TiO2 particles have smaller size of crystal grains and higher specific surface area due to the restraint of SO42- from the grain growth. Under the same measured condition and electric field strength of 3kV/mm, the ratio of field-induced shear stress to zero field shear stress (tau(E)/tau(0)) of TiO2 particles is 80, while that of H2SO4-modifiedmodified TiO2 particles is more that 500. The observed ER performances are reasonably explained by the stronger interfacial polarization, which is brought by the specific structures of the H2SO4-modified TiO2 particles.