Synthesis and electrorheological characteristics of sea urchin-like TiO(2) hollow spheres

Abstract

TiO(2) hollow microspheres with sea urchin-like hierarchical architectures were synthesized by a simple hydrothermal method. The as-synthesized hollow microspheres with hierarchical architectures consisting of many rhombic building units exhibit high specific surface area. Electrorheological (ER) properties of hierarchical hollow TiO(2)-based suspension were investigated under steady and oscillatory shear. The hollow TiO(2)-based suspensions show much higher yield stress and elasticity than pure TiO(2) suspension at the same electric field strength. This phenomenon was elucidated well in view of their dielectric spectra analysis. The sea urchin-like architectures result in stronger interfacial polarization of hollow TiO(2) suspension upon an electric field, showing higher ER activity. Also, hollow interiors of TiO(2) particles increase the long-term stability of suspensions and further merit the ER effect.