Poly(methylaniline) (PMA) was chemically synthesized and its polymerization was confirmed via an FT-IR. Anhydrous electrorheological (ER) fluid consisting of semiconducting PMA particles dispersed in silicone oil was then prepared, and its mechanical properties such as tensile and compressive stresses were experimentally investigated using a squeeze mode type apparatus that was devised by integrating a motion controller and data acquisition system. The intensity of electric field, electrode velocity, and initial gap were chosen as important test parameters that influence the tensile and compressive characteristics of the ER fluid. The maximum tensile stresses were evaluated at each condition, and a microstructure was also investigated during compressive motion. (c) 2005 Wiley Periodicals, Inc.