Study on Electrorheological Fluid Containing Polyaniline Particles

The static electrorheological properties of suspensions containing doped polyani-line(PAn) particles,pretreated with alkaline agent,in insulating oil No.2 under direct cur-rent high electric field were studied as functions of dielectric constants, conductivity (σ),vol-ume fraction of the particles as well as applied electric field strength. The results showed that the PAn particles of the same σ pretreated by ammonia water possessed higher dielectric constants than those pretreated by aqueous NaOH. In the former case yield stress of the sus-pension increased nonlinearly with dipolar coefficient square when σ of PAn was low enough, i.e. σ≤1.0×10^-7S/cm, while in the latter case a maximum yield stress occurred. As a re-sult anhydrous suspensions with high electrorheological activity can be obtained using PAn particles pretreated with alkaline agent to a certain pH value.