Nanostructured Conducting-Polymer Coatings and Anticorrosion Protection

4 Nanostructured Conducting-Polymer Coatings and Anticorrosion Protection 

New research trends have emerged in the last few years in which nano- or microstructuring of coatings (or some parts of coatings) is used to overcome some of the problems described above and to improve their anticorrosion properties. 

As shown previously, anticorrosion properties are the result of a complex steady-state situation in which several phenomena are in action (i) displacement of the electrochemical interface, (ii) ennobling and self-healing effects, (iii) barrier effect offering nonspecific protection. 

Protection mechanisms (i) and (iii) are ineffective when a defect appears in a coating, and mechanism (ii) will fail for large defects, even though it may induce excellent protection for small ones. Furthermore, delamination of the coating upon reduction of the conductive polymer as well as the progressive incorporation of water and electrolyte within the coating can be responsible for failure. 

In any cases, it is clear that adhesion of the ECP on the metal is an essential requirement for anticorrosion properties. It is also clear that O2 and electrolyte diffusion inside a coating has to be avoided. It is against these two main causes of failure that micro- and nanostructuring of coatings can bring new improvements. 

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