Counterion and Diluent Effects on the Response of Ionic Polymer Transducers

A parametric study is presented which investigates the effect that counterion and diluent have on the electrical and electromechanical response of the ionic polymer transducers (IPT). This series of experiments expands upon existing studies by incorporating the sensing and impedance characteristics of the ionic polymer in response to changes in the counterion species and the viscous and dielectric properties of the diluent. The counterions considered in this study include the monovalent and divalent metals Li ⁺ , Na ⁺ , Cs ⁺ , and Ca ²⁺ , as well as the larger organic cations tetraethylammonium (TEA ⁺ ) and tetrabutylammonium (TBA ⁺ ). Viscosity studies incorporate various water—glycerol mixtures which are tailored to yield viscosities from 1 cP (100% water) to 1500 cP (100% glycerol). Dielectric properties of the diluent are also considered in a study which compares the response of samples in water (78.4), acetonitrile (37.5), and butyl acetate (5.4). The results of these studies demonstrate the importance of the transducer's electrical response in regards to the electromechanical performance of the transducer in both actuation and sensing applications.