Cyclic voltammetry and microwave characterisation of smart materials based on polymer electrolyte composites

The fabrication of conducting polymer - silver-polymer electrolyte composite materials is described. Discs of these materials mounted in a coaxial test fixture exhibit rapid and reversible changes in their microwave impedance when small electric fields are applied across them. The effect of the concentration of conducting polymer on the cyclic voltammetry and microwave characteristics of the composites is discussed. Comparison of the cyclic voltammetry and microwave results has shown that changes in the gradients of the cyclic voltammograms coincide with large changes in microwave reflectivity The results are consistent with the conducting polymer being switched from an insulating to a conducting state when the fields are applied. The reverse change occurs when the field is removed. Microwave coaxial line measurements for annular samples are presented and an equivalent network model comprising a parallel resistor and capacitor has been fitted to the measured data. Scanning electron microscopy studies on both the cycled and uncycled composites are presented and the results suggest that, during cycling, the silver metal dissolves and is then re-precipitated.