Stabilization of Metal-Metal Oxide Surfaces Using Electroactive Polymer Films

Charge coupling of the catalyzed reduction of O₂ on platinized poly(3-methylthiophene) [P(3-MT)] films to the anodic dissolution of Ti is reported. Specifically, the redox polymer with Pt catalyst is used in these studies to mediate electrons generated by Ti dissolution and consumed by O₂ reduction. Due to the large redox polymer capacity (>55 F/cm³) of P(3-MT), these reactions occur at a stable potential approximately equal to the reversible oxidation potential of the polymer. Data presented support the conclusion that O₂ reduction on the polymer film can replenish polymer charge consumed by metal dissolution, thereby stabilizing the potential of Ti within the passive potential range and minimizing the rate of metal dissolution. O₂ reduction on P(3-MT)/Pt is sufficiently fast to poise the potential of Ti at 0.55V vs. SCE for pH ≈ 3.2 and for metal-to-polymer geometrical area ratios (A_Ti/A_PMT) ≤ 10. these results suggest possible applications of redox polymers as porous cathodes for metal stabilization.