Electrorheological characteristics of polyaniline and its copolymer suspensions with ionic and nonionic substituents

Electrorheological (ER) characteristics of ER fluids, composed of suspensio ns of semiconducting polyaniline and two different copolyaniline particles in silicone oil, were determined experimentally. Ionic sodium diphenylamine sulfonate and nonionic o-ethoxyaniline were used to synthesize copolyanili nes, i.e. N-substituted copolyaniline and poly(aniline-co-o-ethoxyaniline), respectively. ER fluids composed of these three different polymers were co mpared with respect to their rheological properties under an applied electr ic field. It was found that ER fluids containing a copolymer with an ionic group exhibited the highest ER performance among polyaniline and its copoly mer systems in a shear-rate region above 1 s(-1).