Tunable stiffness of electrorheological elastomers by designing mesostructures

Electrorheological elastomers have broad and important applications. While existing studies mostly focus on microstructures of electrorheological elastomers, their mesoscale structures have been rarely investigated. We present a theory on the design of mesostructures of electrorheological elastomers that consist of two phases with different permittivity. We show that the deformation of elastomers can reorient their mesostructures, which consequently results in variations of their effective permittivity, leading to stiffening, softening, or instability of the elastomer. Optimal design of the mesostructures can give giant tunable stiffness. Our theoretical model is further validated by results from numerical simulations.