Magnetorheological elastomers: Properties and applications

Magnetorheological (MR) elastomers are viscoelastic solids whose mechanical properties are controllable by applied magnetic fields. We have developed a family of MR elastomers, comprising micrometer-sized carbonyl iron particles embedded in natural rubber, that can be processed using conventional rubber-mixing techniques. By crosslinking the elastomer in the presence of an applied magnetic field, field-induced interparticle interactions promote the formation of particle chains and columns aligned along the field direction. The resulting composites possess field-dependent mechanical storage and loss moduli as well as anisotropic mechanical and magnetic properties. The field dependence of the mechanical properties of MR elastomers enables the construction of controllable elastomeric components, such as suspension bushings, that may prove advantageous in some automotive applications.