Conductive polyaniline (doped PAni) was synthesized by a chemical method in media containing, respectively, hydrochloric (HCl) and formic acid (HCOOH). The FT-IR and Raman results showed that the doping degree of PAni-HCOOH is greater than that of the PAni-HCl. Additionally, the Raman studies indicated that the oxidation degree of PAni-HCOOH is higher than that of PAni-HCl, and that polaron segments dominate the PAni-HCOOH structure. The thermogravimetric analysis (TGA) in oxidizing atmosphere also suggests that the doping level of PAni with HCOOH is higher than that of PAni with HCl. The DSC results confirm the differences of the thermal degradation mechanism, in non oxidative atmosphere, of the polymeric chain of both polyanilines. The electrical conductivity of the PAni-HCOOH was 7.51 S cm-1 , while that of the PAni-HCl was 0.143 S cm-1 confirming the results of FT-IR, Raman and TGA, i.e., the oxidation and the doping degree of PAni-HCOOH is higher than that of PAni-HCl.

A síntese eletroquímica de filmes de polipirrol em superfícies de alumínio, em meio aquoso contendo ácido tartárico e pirrol, foi realizada através da técnica galvanostática e por voltametria cíclica. Um mecanismo que considera o crescimento de uma camada porosa de óxido de alumínio em paralelo com a eletrodeposição do filme de polipirrol foi proposto. Foi observado que quanto mais homogênea a distribuição dos poros na camada de óxido, menor a resistência oferecida para o crescimento dos filmes de polipirrol. Também foi observado que os filmes de polipirrol depositados por voltametria cíclica são menos uniformes do que aqueles formados galvanostaticamente. Filmes eletrodepositados galvanostaticamente a maiores densidades de corrente são mais propensos ao processo de superoxidação, como mostram os resultados de FTIR. Além disso, filmes de polipirrol depositados a 2,5 mA cm -2 apresentam um melhor desempenho na proteção de superfícies de alumínio contra corrosão.The electrochemical synthesis of polypyrrole films on aluminum surfaces from aqueous solutions containing tartaric acid and pyrrole was performed using cyclic voltammetry and galvanostatic techniques. A mechanism that considers a porous aluminum oxide layer growing in parallel with the polymeric film explains the polypyrrole electrodeposition on aluminum surfaces. The more homogeneous the distribution of pores on the aluminum oxide layer, the smaller is the resistance offered to the polypyrrole film growth. Polypyrrole films deposited by cyclic voltammetry are much less uniform than those galvanostatically formed. Polymeric films galvanostatically deposited at higher current densities were more susceptible to overoxidation processes than those films formed at lower current densities, as demonstrated by FTIR analyses. Furthermore, films formed at low current density perform better on protecting aluminum surfaces against corrosion.

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