Poly(ionic liquid)s having coumarate counter-anions as corrosion inhibitors in acrylic UV coatings

Organic inhibitor alternatives to toxic chromium treatments are being sought to protect metal surfaces. One of the limitations of the organic inhibitors is leaching out of the coatings limiting their performance. This work investigates the ionic attachment of coumarate inhibitors into a poly(ionic liquid), polyDADMA coumarate, and its application in a UV-cured acrylic coating. The corrosion protection of the polyDADMA coumarate coating was evaluated by electrochemical techniques including electrochemical impedance spectroscopy (EIS) and surface characterization. The adhesion of the acrylic UV coating formulation onto the steel surface was also investigated. The results showed that the presence of poly(ionic liquid) coumarate in the blend improves the adhesion level as well as providing active corrosion protection.