Coatings Made from Conducting-Polymer Formulations

2 Coatings Made from Conducting-Polymer Formulations 

The main difficulties related to electropolymerization processes have been ruled out, and theoretically, no metal specificity is involved in the procedure which could restrict the application, except the case of PANI whose acidity properties can conflict with different metal oxides, as previously stated in Section 16.2. The main problem lies in the fact that all the conducting polymers are generally insoluble and, therefore, mixing them with paint will involve either the fabrication of particle dispersions or functionalization of the polymer in order to make it soluble in an organic solvent. Initially centred on PANI formulations, the process has been progressively extended to other conducting polymers like PPy, PT, and their derivatives. 

Much work has been devoted to the use of PANI formulations for the protection of metals against corrosion. Two main methods of application have been described. In one case, the PANI formulation is applied to the metal as a primer, and then top-coated by a conventional polymer layer. In the second case, the PANI is diluted in a polymer matrix it may be a blend of PANI and another polymer, or it may be included in the coating. 

Many publications have appeared during recent years and some results seem very promising. 

Very interesting results were obtained by Gelling et al. [141] with poly-3-octyl pyrrole (POPy) and poly-3-octadecyl pyrrole (PODPy) solubilized in an organic solvent and cast on Al 2024 T3 (2-3 pm thick), then top-coated by a 20 pm-thick polyurethane (PU) 

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