▎ 摘　　要

Graphene oxide/copolyaniline (GO/NCOPA) composites were prepared with GO, which was prepared using a modified Hummers method and a monomer mixture containing aniline and ionic sodium diphenylamine sulfonate, where ionic N-substituted copolyaniline was synthesized by chemical oxidation. The GO/NCOPA composite, as a dry-base electrorheological (ER) fluid system, was dispersed in silicone oil. With the ionic substituent on the polymer chain, the composite showed both controllable electrical conductivity and higher polarization, which provide favorable factors for ER applications. The GO/NCOPA composite-based ER fluid containing a copolymer with an ionic group exhibited typical ER characteristics, as measured using a rotational rheometer equipped with a Couette-type cylinder and a high voltage generator. The dielectric spectra measure was correlated further with their ER performance.