Sedimentation behaviour of hierarchical porous TiO2 microspheres electrorheological fluids. (September 2015) - Ma, Limin
Increasing the specific surface area of particles improves the suspension stability of electrorheological fluids. In this study, we introduced three TiO2 electrorheological materials, namely, mesoporous TiO2 : Ce 4+, hollow TiO2 : Ce 4+ and mesoporous hollow TiO2, all of which possess better sedimentation stability than pure solid TiO2 electrorheological materials. We aim to highlight the advantages of nanostructured materials with large surface area in improving the sedimentation stability of electrorheological fluids. The results indicated that the suspension composed of Ce-doped mesoporous TiO2 particles in silicone oil exhibited a strong electrorheological effect. The yield stress of a typical Ce-doped TiO2 electrorheological fluid was approximately 5.0 kPa at 1.5 kV/mm and 6.0 kPa at 2 kV/mm, which were 10 times higher than that of pure TiO2 electrorheological fluid. Hollow TiO2 : Ce 4+ spheres using the polymer polystyrene as the hollow template not only showed good electrorheological effect but also greatly increased settleability. The specific surface area of the mesoporous TiO2 hollow spheres was twice that of the mesoporous TiO2 and thus showed better suspension stability.