Electromechanical response of electrorheological fluids and poly(dimethylsiloxane) networks

A novel type of electromechanical actuator that utilizes the speed of elect rorheological fluids (ERFs) coupled with the elastic response of polymeric gels has been investigated. ERF's were made using polyaniline (PANI) partic les suspended in a trimethyl-terminated poly(dimethylsiloxane) (3MPDMS) flu id. These ERF's were then cured into matrices of both ordered and randomly cross-linked PDMS networks (XPDMS). Electric fields were applied to these s ystems using flexible electrodes. Both electrode displacement and compressi on modulus of the composite gels were measured as a function of cross-link density of the gels, viscosity, and electrical properties of the 3MPDMS flu id, conductivity and dielectric constant of both the pure PANI and the gel matrix, weight percent PANT in the ERF, volume percent ERF in the final gel composite, and applied electric field strength. The do electric field requ ired to move the electrodes toward each other by a fixed distance depended more on the type and amount of crosslinking in the XPDMS matrix, the viscos ity 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 add ition, the results indicated that the motion generated by this actuator als o depends on the amount of force exerted on the electrodes by the polarized ERF particles in the gels.