Abstract
The degradation reaction kinetics of oxidized polyaniline has been studied employing rotating ring‐disk electrode techniques. Polyaniline films were grown on the disk electrode and were then oxidized at a potential more positive than 0.90V vs. 
, while the degradation product (benzoquinone) was monitored at the ring electrode at an applied potential of 0.05V. The product was monitored either with the disk potential maintained at >0.90V (closed‐circuit experiment) or with the disk circuit disconnected after the polyaniline film was oxidized for some time (open‐circuit experiment). The results of closed‐circuit experiments indicate that electrochemical generation of oxidized polyaniline was a limiting step and its rate decayed for a given amount of polyaniline film according to the zeroth order. The rate of hydrolysis for the oxidized polyaniline in quinonoid forms was determined to be consecutive first order from open‐circuit experiments. The dependencies of the hydrolysis reaction on the acidity of the degradation medium and sulfate concentrations have also been studied; the results are consistent with the Schiff base hydrolysis mechanism.