Synthesis and electrorheological characteristics of polyaniline-titanium dioxide hybrid suspension

Abstract

Conducting polyaniline (PANI)/titanium dioxide (TiO 2) hybrid particles were synthesized via an oxidation polymerization in the presence of TiO 2, and their electrorheological (ER) characteristics were examined, since the formation of an organic/inorganic hybrid exhibits various advantages from the combination of their unique properties as a part of our efforts to find highly potential ER-active particles using conducting polymers. The TiO 2 nanoparticles possess a relatively high dielectric constant which is important for polarization in the ER response, in which the ER fluids are a class of colloidal suspensions which show a transition from a liquid-like to a solid-like state under an applied electric field. Synthesized PANI/TiO 2 composites in this study were characterized by an FT-IR, thermogravimetry analysis, and scanning electron microscopy. We then prepared the PANI/TiO 2 composites-based ER suspension with insulating oil and investigated its ER behavior as a function of shear rate under an applied electric field. The fast relaxation time of PANI/TiO 2 hybrid was expected to enhance electrostatic force over shear force under a shear flow, showing the improved ER performance. Furthermore, it was also found that the properties of TiO 2 affect the dielectric of PANI/TiO 2 composites to give better ER properties.