Pedot conducting polymers as corrosion inhibitors additives for acrylic-uv coatings

Conductive Polymers (CPs) have gained interest as a promising alternative to standard corrosion-protective coatings. Among CPs, polyaniline and polypirrole are the most widely known, however, they present some critical issues related to their stability and toxicity. This, together with the limited offer of CPs for corrosion inhibition coatings, strongly limits their wide scale application. In this work, we present a new class of corrosion-protective coatings incorporating one of the most stable and low toxicity CPs poly(3,4-ethilenedioxythiophene), commonly known as PEDOT, doped with different counter-anions that themselves also have corrosion inhibition (C.I.) properties. These dopants include three alkyl phosphates and a cinnamate derivative. These new PEDOT: C.Is. polymers were incorporated into an acrylic formulation at different concentrations and UV cured to obtain polymer coatings. The corrosion reduction properties of the coatings applied onto mild steel surfaces were tested in sea-like conditions (NaCl (aq) 3.5 wt%) through Potentiostatic Electrochemical Impedance Spectroscopy (PEIS), Potentiodynamic Polarization (PP), and exposure to harsh environment in a salt spray chamber. The results obtained from the electrochemical characterization showed that the new PEDOT:C.I. coatings present efficiencies up to 99 % and exhibited improved resistance to corrosive environment compared to the reference UV-acrylic coating. These CP-containing coatings demonstrated effective protection of the metal surface from corrosion, indicating their potential as viable alternatives to standard corrosion-protective coatings while being more environmentally friendly.