Dear Dr. Amirhossein Esmaeilkhanian ,

only different approaches develope for the use of CPs in protective coatings (dopants, composites, blends) in addition with a suitable choice of synthesis parameters can lead to an improvement in the anticorrosion properties of the coatings prepared by CPs for metals and their alloys. These precautions still have to be sometimes calibrated and tested for each individual, specific situation.

I suggest you to have a look at the following, interesting papers:

- Layers of Inhibitor Anion – Doped Polypyrrole for Corrosion Protection of Mild Steel

By Le Minh Duc and Vu Quoc Trung

In Book Material Science –Advanced Topics, Edited by Yitzhak Mastai, IntechOpen 2013, ISBN: 978-953-51-1140-5

Available at: https://www.intechopen.com/books/materials-science-advanced-topics/layers-of-inhibitor-anion-doped-polypyrrole-for-corrosion-protection-of-mild-steel

-Conducting polyaniline nanocomposite-based paints for corrosion protection of steel

Dimitra Sazou, Pravin Pralhad Deshpande,

Chemical Papers- Slovak Academy of Sciences 71(2):1-29 (2016)

Available, as abstract on RG, at: https://www.researchgate.net/publication/312064288_Conducting_polyaniline_nanocomposite-based_paints_for_corrosion_protection_of_steel

- Electro Polymerization of Polypyrrole Coatings Doped with Different Proton Acids for Corrosion Protection of 304 Stainless Steel

Li Jiang, Haibo Ma, Jiaqi Zhang, Yu Lu,Hongbin Lu, andXiangkang Meng

ICMSNT 2017 - MAT EC Web of Conferences, 109, 03007 (2017)

Available at: https://www.researchgate.net/publication/317262098_Electro_Polymerization_of_Polypyrrole_Coatings_Doped_with_Different_Proton_Acids_for_Corrosion_Protection_of_304_Stainless_Steel/fulltext/593199faa6fdcc89e7a21868/Electro-Polymerization-of-Polypyrrole-Coatings-Doped-with-Different-Proton-Acids-for-Corrosion-Protection-of-304-Stainless-Steel.pdf

- Polypyrrole/Metal Oxides-Based Composites/Nanocomposites for Corrosion Protection

Niteen Jadhav, Subramanyam Kasisomayajula and Victoria Johnston Gelling

Front. Mater., (2020)

Available at: https://www.frontiersin.org/articles/10.3389/fmats.2020.00095/full

- Polypyrrole Modified E-Coat Paint for Corrosion Protection of Aluminum AA1200

Giseli Contri, Camila Aparecida Zimmermann, Sílvia Daniela Araújo Da Silva Ramoa, Débora Pereira Schmitz, Luiz Gustavo Ecco, Guilherme Mariz de Oliveira Barra, and Michele Fedel

Front. Mater., (2020)

Available at: https://www.frontiersin.org/articles/10.3389/fmats.2020.00045/full

Enjoy reading and my best regards, Pierluigi Traverso.

Amirhossein - I'm not an expert in this field. However, to my knowledge, the opposite is the case. According to the attached review article, conducting polymers (CPs) such as polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) are used for the corrosion protection of metals and metal alloys. The article is entitled "Conducting polymers for corrosion protection: a review".

Two related article are available on RG, but unfortunately not as public full texts. Perhaps you can request the full texts directly from the author if they are of interest to you.

1. Article Corrosion Protection and Conducting Polymers: Polypyrrole Fi...

2. Article Conducting polymers for corrosion protection: A review

Frank T. Edelmann

Dear Frank, I know that they are widely used due to their anticorrosive behavior, however there are some reports about non-applicability of CPs and their failure for protection.

All in all thanks for your response.

Yes dear Amirhossein Esmaeilkhanian, to the my best knowledge I think you are right in raising the issue of CPs applicability as there is no complete agreement between the research outputs regarding the corrosion protection properties provided by the such coatings materials.

Now, as you asked in your question for supporting references, I found for you that the recent short introduction by Maryam Eslami et tal., containing a bundle of details supporting your issues as well as the previous vital work by Pravin Pralhad Deshpande et al..

Hope the above references are helpful.

Best regards

Article Electropolymerization and Possible Corrosion Protection Effe...

https://link.springer.com/article/10.1007%2Fs11998-014-9586-7

Dear Mohammed Hussein j. H. Al'Atia

Thanks for your answer. Best regards

Dear Dr. Amirhossein Esmaeilkhanian ,

only different approaches develope for the use of CPs in protective coatings (dopants, composites, blends) in addition with a suitable choice of synthesis parameters can lead to an improvement in the anticorrosion properties of the coatings prepared by CPs for metals and their alloys. These precautions still have to be sometimes calibrated and tested for each individual, specific situation.

I suggest you to have a look at the following, interesting papers:

- Layers of Inhibitor Anion – Doped Polypyrrole for Corrosion Protection of Mild Steel

By Le Minh Duc and Vu Quoc Trung

In Book Material Science –Advanced Topics, Edited by Yitzhak Mastai, IntechOpen 2013, ISBN: 978-953-51-1140-5

Available at: https://www.intechopen.com/books/materials-science-advanced-topics/layers-of-inhibitor-anion-doped-polypyrrole-for-corrosion-protection-of-mild-steel

-Conducting polyaniline nanocomposite-based paints for corrosion protection of steel

Dimitra Sazou, Pravin Pralhad Deshpande,

Chemical Papers- Slovak Academy of Sciences 71(2):1-29 (2016)

Available, as abstract on RG, at: https://www.researchgate.net/publication/312064288_Conducting_polyaniline_nanocomposite-based_paints_for_corrosion_protection_of_steel

- Electro Polymerization of Polypyrrole Coatings Doped with Different Proton Acids for Corrosion Protection of 304 Stainless Steel

Li Jiang, Haibo Ma, Jiaqi Zhang, Yu Lu,Hongbin Lu, andXiangkang Meng

ICMSNT 2017 - MAT EC Web of Conferences, 109, 03007 (2017)

Available at: https://www.researchgate.net/publication/317262098_Electro_Polymerization_of_Polypyrrole_Coatings_Doped_with_Different_Proton_Acids_for_Corrosion_Protection_of_304_Stainless_Steel/fulltext/593199faa6fdcc89e7a21868/Electro-Polymerization-of-Polypyrrole-Coatings-Doped-with-Different-Proton-Acids-for-Corrosion-Protection-of-304-Stainless-Steel.pdf

- Polypyrrole/Metal Oxides-Based Composites/Nanocomposites for Corrosion Protection

Niteen Jadhav, Subramanyam Kasisomayajula and Victoria Johnston Gelling

Front. Mater., (2020)

Available at: https://www.frontiersin.org/articles/10.3389/fmats.2020.00095/full

- Polypyrrole Modified E-Coat Paint for Corrosion Protection of Aluminum AA1200

Giseli Contri, Camila Aparecida Zimmermann, Sílvia Daniela Araújo Da Silva Ramoa, Débora Pereira Schmitz, Luiz Gustavo Ecco, Guilherme Mariz de Oliveira Barra, and Michele Fedel

Front. Mater., (2020)

Available at: https://www.frontiersin.org/articles/10.3389/fmats.2020.00045/full

Enjoy reading and my best regards, Pierluigi Traverso.

Dear Pierluigi Traverso and Mohammed Hussein j. H. Al'Atia

I really appreciate you for your answer. However, in the mentioned studies, PPy has improved the corrosion protective property of substrates.

I know it.

But, the thing I want is as follows: In some cases, PPy, instead of lowering the corrosion rate, leads to acceleration of corrosion rate and leads to failure of substrate!

Please send me such studies in which PPy lowers the corrosion property of the substrate. Best regards

Dear Dr. Amirhossein Esmaeilkhanian ,

below some examples in which the use of CPs as protective coating has been questioned:

- A study on mechanism of corrosion protection of polyaniline coating and its failure

Jianjun Fang, Ke Xu, Lihua Zhu, Zhixiong Zhou, Heqing Tang

Corrosion Science 49(11):4232-4242 (2007)

Available, as abstract on RG, at:

https://www.researchgate.net/publication/248209033_A_study_on_mechanism_of_corrosion_protection_of_polyaniline_coating_and_its_failure

- Conducting polymers for corrosion protection: What makes the difference between failure and success?

Michael Rohwerder, Adam Michalik

Electrochimica Acta 53(3):1300-1313 (2007)

Available, as abstract on RG, at: https://www.researchgate.net/publication/222056292_Conducting_polymers_for_corrosion_protection_What_makes_the_difference_between_failure_and_success

- Conducting Polymers for Corrosion Protection: A Critical View

Adam Michalik, Michael Rohwerder

Zeitschrift für Physikalische Chemie 100(10) (2009)

Available, as abstract on RG, at: https://www.researchgate.net/publication/41470797_Conducting_Polymers_for_Corrosion_Protection_A_Critical_View

- In situ investigation of corrosion localised at the buried interface between metal and conducting polymer based composite coatings

Michael Rohwerder, Le Minh Duc, Adam Michalik

Electrochimica Acta 54(25) (2009)

Available, as abstract on RG, at: https://www.researchgate.net/publication/41470800_In_situ_investigation_of_corrosion_localised_at_the_buried_interface_between_metal_and_conducting_polymer_based_composite_coatings

- Application of the Kelvin Probe method for screening the interfacial reactivity of conducting polymer based coatings for corrosion protection

Michael Rohwerder, Sena Işik, Amarnath Chellachamy Anbalagan

Electrochimica Acta 56(4) (2011)

Available, as abstract on RG, at: https://www.researchgate.net/publication/47818012_Application_of_the_Kelvin_Probe_method_for_screening_the_interfacial_reactivity_of_conducting_polymer_based_coatings_for_corrosion_protection

- The Protection Zone: A Long-Range Corrosion Protection Mechanism around Conducting Polymer Particles in Composite Coatings: Part I. Polyaniline and Polypyrrole

A. Merz, Matthias Schulz, Michael Rohwerder

Journal of The Electrochemical Society 166(12):C304-C313 (2019)

Available, as afull text on RG, at: https://www.researchgate.net/publication/334584473_The_Protection_Zone_A_Long-Range_Corrosion_Protection_Mechanism_around_Conducting_Polymer_Particles_in_Composite_Coatings_Part_I_Polyaniline_and_Polypyrrole

Best regards, Pierluigi Traverso.

Dear Amirhossein Esmaeilkhanian

I'm afraid you missed going through the introduction that I mentioned in my previous answer. Please do now and then you can see that both references 35 and 39 offer what, you want.

Best regards