Dodecylbenzene-sulfonic acid (DBSA)-doped polyaniline (PANI) was prepared by emulsion polymerization, where DBSA was used as both an emulsifier and a dopant. The chemical structure and morphology of the DBSA were examined via FF-IR and SEM, respectively. Electrorheological (ER) properties of DBSA-doped PANI particles dispersed in silicone oil were studied under different operating temperatures and an applied electric field. Shear stress data as a function of shear rate fitted quite well with the Cho-Choi-Jhon (CCJ) shear stress model. Both deduced static and dynamic yield stresses were found to be collapsed into a universal scaling function. Furthermore, the Cole-Cole plot and the dielectric spectra gave relaxation times of the ER systems for different operating temperatures of dielectric measurements, confirming the correlation of dielectric properties with ER performance. (C) 2007 Elsevier Ltd. All rights reserved.