Preparation method of polyaniline anti-corrosion coating

 1. Electrochemical deposition method

Electrochemical deposition method refers to the formation of PANI coating on the metal surface by electrochemical method, mainly including constant current method, constant potential method, pulse polarization method and dynamic potential scanning method. PANI is generally polymerized in acidic solution. Since the electrode material, potential, and pH value of the electrolyte solution all have a certain influence on the polymerization of aniline, the conditions used in the current preparation method of PANI coating are still not uniform. Bemard MC et al [14] synthesized polyaniline film by constant potential method, and studied its influence on substrate surface passivation under different acidic conditions. But this method is difficult to apply to larger metal parts, so its application is still limited.

2. Co-dissolution

Co-dissolution refers to mixing PANI with traditional polymer solvents to form a co-solvent for coating, and a coating will be formed after the solvent evaporates. This method also has certain disadvantages: because PANI has low solubility in organic solvents, although it has certain solubility in high boiling point solvents, the boiling points of these solvents are all high, which has a certain impact on the coating quality. Moreover, most of these solvents are toxic, expensive, and limited in application. Mari et al. [15] used this method to develop PANI epoxy resin anti-corrosion coatings.

3. Blending

Blending refers to the use of PANI as an additive to existing anti-corrosion coatings, mixed with conventional coatings such as epoxy resin for coating, and the interaction and chemical bonds between PANI and other components are used to improve the anti-corrosion of this blended coating. performance. This method is currently the most widely used method for PANI anti-corrosion research. Studies have shown [16-17] that the anti-corrosion coating prepared by blending PANI and resin not only has anodic protection, but also has better adhesion and water shielding than the previous two methods. way.