Corrosion of conductive polypyrrole: Effects of possibly formed galvanic cells

Some galvanic couples were designed with PPy films to simulate possibly formed corrosion cells on PPy. Their effects on the corrosion of PPy were investigated using electrochemical methods and XPS analysis. The results indicate that the PPy redox state difference cell just occurs in the initial corrosion period and can not be sustained on PPy. The H+ ion and electrolyte concentration difference cells can be sustained on PPy but do not influence the corrosion of PPy. The oxygen concentration difference cell can also be sustained on PPy and severely accelerates the corrosion of PPy. The mechanism involved is discussed. (C) 2013 Elsevier Ltd. All rights reserved.