EQCM measurement of polymerization and ion exchange properties of polypyrrole (PPy/DS~-)thin film

Polypyrrole films doped with dodecylsulfate (PPy/DS-)were synthesized on platinum substrates by electrochemical polymerization and the film-electrode systems were investigated as electrochemically switched ion exchange materials.Electrochemical quartz crystal microbalance (EQCM)technique was used to investigate the polymerization mechanism of the PPy/DS- film.Combined with Cyclic Voltammetry (CV)and X-ray photoelectron (XPS),the electrochemical behavior and ion loading/unloading mechanism of PPy/DS- film electrodes were also investigated in electrolytes of alkali-metals and alkaline-earth metals.Experimental results indicated that PPy/DS- film had good electroactivity.The oxidation and reduction process of PPy/DS- film were accompanied by cation exchange and anion exchange simultaneously,and cation or anion exchange could be performed singly by controlling scan potential.In CsNO3 solution,only Cs+ could be exchanged when the thin film was scanning between -1.05 V and 0.14 V.The cycle life in alkali-metals nitrates was better than that in alkaline-earth metals nitrates,especially in CsNO3 solution.