Modeling the natural degradation kinetics of conducting polypyrrole for service failure prediction in NaOH aqueous media

The degradation of electrochemical activity is the inevitable and noticeable issue in the widespread applications of conducting polypyrrole (PPy), which involves chemical and electrochemical reactions in PPy natural degradation processes. Based on thorough insights into PPy degradation behavior, this work develops a method of theoretical derivation for the natural degradation kinetics model of PPy, which is verified in NaOH aqueous electrolytes and could be further generalized in other media. The kinetics model derives the rate equations of the chemical and electrochemical processes ( v c and v e ) in PPy degradation. The relationships of the electroactivity degradation rate constant ( k deg ) and rate constants of the chemical and electrochemical processes ( k c and k e ) as well as reaction orders of PPy n+ and OH − are established through theoretical deduction. The effects of doping anions in PPy, film thickness, and electrolyte temperature on the degradation kinetics are investigated through theoretical considerations and experimental findings. The degradation level and service failure time of PPy can be effectively predicted using the kinetics model. Establishing the degradation kinetics model would signal the new perspective and depth in comprehensive studies of PPy degradation, finally facilitating the optimization of performance management in PPy practical applications.