Electrorheological properties of suspensions of PAn-PEO-PAn triblock copolymer particles

The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α, ω-bis(p-aminophenyl) poly(ethylene glycol) and characterized by FT-IR and TEM. The experimental results show that the copolymer particles are of a typical core-shell structure after the self-assembly process in water. Its conductivity is much lower than that of the pure PAn. The suspension containing 20 vol% PAn-PEO-PAn triblock copolymer in silicone oil exhibits a typical electrorheological (ER) effect in DC electric field, while it shows a lower leakage current density than that of the pure PAn-based ER fluids. Therefore, the PEO shell hinders the electric hop among PANI chains and decreases the current density of ER fluids in an external electric field, at the same time the interface polarity improves the ER effects.