Electrosynthesis and DSC Characterization of Doped Polypyrrole Films with Sodium Salicylate and Sodium Ibuprofen on the Mg Alloy AZ31

In this work we investigate the effect of the incorporation of salicylate and sodium ibuprofen in the electrodeposition mechanism and thermal properties of polypyrrole films deposited on the magnesium AZ31 alloy. The identification of adsorbed species on the surface of the electrode is performed by means of Infrared and Raman spectroscopy, while the thermal properties of the doped polypyrrole films are characterized by Differential Scanning Calorimetry. The results obtained demonstrate the chemisorption of a Mg-salicylate complex on the surface of the AZ31 alloy as well as the formation of a Mg-ibuprofen complex that hinders the access of the pyrrole monomer to the surface of the electrode and affects the polymerization mechanism at concentrations of ibuprofen in the medium > 20 mM. The DSC thermograms demonstrate a reduction of the Tg of the polymer with the incorporation of ibuprofen, which corresponds to a change in the conformation of the polypyrrole.