Electromechanical Response of Electrorheological Fluids and Poly(dimethylsiloxane) Networks

Abstract

A novel type of electromechanical actuator that utilizes the speed of electrorheological fluids (ERFs) coupled with the elastic response of polymeric gels has been investigated. ERF's were made using polyaniline (PANI) particles suspended in a trimethyl-terminated poly(dimethylsiloxane) (3MPDMS) fluid. These ERF's were then cured into matrices of both ordered and randomly cross-linked PDMS networks (XPDMS). Electric fields were applied to these systems using flexible electrodes. Both electrode displacement and compression modulus of the composite gels were measured as a function of cross-link density of the gels, viscosity, and electrical properties of the 3MPDMS fluid, conductivity and dielectric constant of both the pure PANI and the gel matrix, weight percent PANI in the ERF, volume percent ERF in the final gel composite, and applied electric field strength. The dc electric field required to move the electrodes toward each other by a fixed distance depended more on the type and amount of cross-linking in the XPDMS matrix, the viscosity of the ERF phase, and whether the ERF particles were prealigned in the XPDMS network than it did on the compression modulus of the systems. In addition, the results indicated that the motion generated by this actuator also depends on the amount of force exerted on the electrodes by the polarized ERF particles in the gels.