Аннотация:A comprehensive study of the cellulose particle shape effect on electrorheological activity of their suspensions in polydimethylsiloxane was performed. Microparticles, nanorods and porous composite particles of cellulose with polyethylene glycol were considered as a filler. The structure of particles was established by a set of complementary methods, such as electron microscopy, infrared spectroscopy, and wide-angle X-ray scattering. The rheological behavior of suspensions filled by various types of particles changes under an electric field. The yield stress increases with electric field strength. The role of particle shape on the electrorheological properties of suspensions was revealed. The values of the yield stress of suspensions increase from microparticles to nanorods and porous composite particles at the same concentration and electric field strength. Porous composite particles of cellulose, a novel filler obtained by freeze-drying, demonstrates an enhanced electrorheological response compared to micro- and nanoparticles. The yield stress reaches 450 Pa at 7 kV/mm at an extremely low concentration of 1.0 wt%. Moreover, the porosity of the particles significantly increases the sedimentation stability of cellulose suspensions in polydimethylsiloxane. The high porosity of the filler makes it possible to obtain highly efficient electrorheological fluids at a sufficiently low concentration of the dispersed phase.