Experimental Characterization of Ionic Polymer Metal Composite as a Novel Fractional Order Element

Ionic polymer metal composites (IPMCs) are electroactive materials made of ionic polymer thin membranes with platinummetallization on their surfaces.They are interesting materials due to not only their electromechanical applications as transducersbut also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Theirelectrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs) with a viewof defining fabrication processes and production strategies that assure the desired performances. In this paper, the experimentalelectrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices withdifferent platinum absorption times (5 h and 20 h) are characterized through experimental data: first, a preliminary linearity studyis performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated aslinear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Suchanalyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponentvalue depends on fabrication parameters as the absorption time.