Cation Sensitivity of a Polypyrrole/Polyanion Composite Film Electrode

Polypyrrole (PPy)/polyanion composite films were formed electrochemically in coexistence with a polymer electrolyte (poly(sodium 4-styrenesulfonate) (PSS) or poly(acrylic acid) (PAA)) in the polymerizing solution. The potential response behaviors of the PPy/PSS and PPy/PAA composites to cation activities were investigated, and the PPy/PSS electrode showed a better Nernstian response than that of the PPy/PAA electrode. The selection of incorporated polyanions and the polymerizing conditions, which were determined in this paper, affected the response behavior. The resultant PPy/PSS electrode showed a good Nernstian response only to monovalent cations with 58 mV/decade. The electrode indicated the equilibrium potential in a few seconds at the change of cation activity. It was found that the potential response was influenced by both the electroactivity of PPy and the PSS content in the PPy matrix.