Electrorheological properties of suspensions of monodispersed micron-sized polyaniline composite particles

Monodispersed micron-sized polyaniline (PANi) composite particles were synthesized by chemically oxidative polymerization of aniline in the presence of functional porous polymer particles. The formation of the PANi-coated composite particles was confirmed by scanning electron microscopy. Electrorheological (ER) properties of the monosized composite particle suspensions were then investigated under different DC electric fields by altering the particle characteristics. The ER effect of the PANi composite suspensions was largely dependent on the composition ratio (PANi loading), the particle conductivity, and the particle concentration. Dynamic oscillation measurements revealed that the applied electric field induced the viscoelastic property of the ER suspensions by generating the chain structures of the suspended particles. (C) 2002 Wiley Periodicals, Inc.