Conjugated Polymers Nanocomposite as Anticorrosion Layers

In order to reduce the intrinsic porosity and to increase the barrier effect of anticorrosion CP-based coatings, composite systems have been considered where one component is a CP and other component can be organic or inorganic. In literature, several recent papers have been published on this topic. Two classes of composites based on CPs could be individuated (Table 10.4). In the first class, the matrix is a CP, usually PANI and its 

CP (PANI, PPy, PEDOT) ncuiopcirticles (clays, carbon nanostructures, oxides, metals) 

In the first class of CPs nanocomposites, the oxides considered as secondary component are titanium dioxide (TiO ), zirconium dioxide (ZrOj), silicon dioxide (SiO ), aluminium oxide (Al O ), cadmium oxide (CdO) and zinc oxide (ZnO) [19, 27, 31, 48-52]. Titanium dioxide nanoparticles have excellent properties such as charge carrier, oxidising power, non-toxicity, chemical and photo stability. Conductive PANI/TiO nanocomposites combine the qualities of PANI and nanocrystalline TiO within a single material, thereby developing multifunctional materials with combined properties which have very strong potential applications. 

The corrosion protection of steel by PANI/TiO coating is based on almost three factors [27,48]. 

Also the addition of metal particles, like zinc, to CPs can lead to a beneficial effect on corrosion protection from CP coatings. Olad [53-54] found out that incorporation of zinc nanoparticles and zinc micro-size particles produces effective PANI/Zn nanocomposite and PANI/Zn composite coatings on iron, respectively. The electrical conductivity of both nanocomposite and composite systems is correlated with the zinc content, and it is higher when Zn particles are nanosized. A similar behaviour has been found in the anticorrosive properties of PANI/Zn coatings because the synergetic effect of zinc nanoparticles is more than that of micro-sized particles. 

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