ABSTRACT
In this work the electrosynthesis of polypyrrole (PPy) on Nitinol from solutions of sulfosuccinic acid (0,25 M) and pyrrole (0,25 M) was studied. The PPy was formed potentiostatically in solutions of pH 1 and 7. As far as we know, this is the first time that the electrodeposition of PPy is carried out in the presence of sulfosuccinic acid.
The morphology of the films was studied by scanning electron microscopy images, observing the typical globular shape of PPy. The presence of S was also determined by X-ray dispersive energy (EDX), confirming that the dopant was incorporated into the polymer matrix. The films formed are very adherent and exhibit acceptable conductivity.
In order to evaluate the corrosion behaviour, different electrochemical experiments were performed in Ringer's solution: measurement of open circuit potential, Tafel plots and linear sweep voltammetry. While both coatings improve the protection of the substrate, the films formed in pH 1 solution offer better results. The analysis of ions in solution by inductive coupled plasma atomic emission spectrometry confirms that the films are protective, preventing the release of Ni ions into the solution.
Keywords
Nitinol; Polypyrrole; Sulfosuccinic acid; Adherence
