Enhanced electrorheological activity of rod-like Fe₃O₄@TiO₂ particles in elastomers and their morphological effect

The properties of dielectric particles play the most important role in the electrorheological (ER) activity of elastomers, however, there is a lack of experimental research on the effect of particle morphology on the properties of ER elastomers (EREs). In this study, spherical and rod-like Fe₃O₄@TiO₂ core–shell particles were synthesized and used to prepare EREs. Particles characterization results showed that both spherical and rod-like Fe₃O₄@TiO₂ exhibited an obvious core–shell structure and similar magnetic properties, with the aspect ratio of rod-like Fe₃O₄@TiO₂ particles was approximately 7:1. Furthermore, the EREs filled with rod-like Fe₃O₄@TiO₂ particles exhibit a higher dielectric constant and sharper dielectric loss peak than those filled with spherical particles, indicating that a larger aspect ratio enhances the dielectric performance. For EREs with the same volume fraction of particles or cured under the same external field, the storage modulus and relative ER effect of EREs filled with rod-like particles are both higher than those of EREs containing spherical particles. Additionally, it can be confirmed that the rod-like particle chain structures have a more significant strengthening effect on the ERE matrix, as evidenced by the rod-like Fe₃O₄@TiO₂ particle filled elastomers exhibiting lower creep strain.