Anticorrosive Effect of New Polymer Composite Coatings on Carbon Steel in Aggressive Environments by Electrochemical Procedures

In this investigation, electrochemical deposition procedures were reported to synthesize a novel composite polymer, 3-methylpyrrole-dodecyl sulfate sodium/3,4-ethylenedioxythiophene (3MPY-SDS/EDOT) coatings, on OL 37 samples for anticorrosion protection. The anionic surfactant dodecyl sulfate sodium used in deposition can have a relevant action on the protective capacity. These coatings were considered by cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) methods. The protective attributes of OL 37 coated with P3MPY-SDS/PEDOT have been examined by potentiostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) procedures in 0.5 M H2SO4. The corrosion rate of the P3MPY-SDS/PEDOT-coated OL 37 sample was found to be approximately nine times lower than that of the uncoated sample. The protective layers of these composites demonstrate an effectiveness of over 90%. The optimal efficiency is obtained by electrochemical deposition of P3MPY-SDS/PEDOT, performed at applied potentials of 1.0 V, 1.2 V, and 1.4 V, with current densities of 3 mA/cm2 and 5 mA/cm2 and a molar ratio of 5:3 at 20 min. The influence of electrochemical polymerization parameters—applied potential, current density, scan rate, cycle number, and monomer ratio—on the protective behavior of P3MPY-SDS/PEDOT layers was analyzed, identifying optimal synthesis conditions. Corrosion examinations confirmed that P3MPY-SDS/PEDOT coatings provide effective protection for OL 37 in a corrosive environment.