بررسي اثر عوامل دوپه كننده كمپلكس‌ساز بر مقاومت خوردگي پوشش پليمري حاوي نانوالياف پلي آنيلين

Here, polyaniline—an efficient and smart anti-corrosion material—was synthesized and then embedded in an epoxy matrix. This study aimed to eva‎luate and compare the role of different doping agents in increasing the corrosion resistance of the used anti-corrosion pigments. Specifically, phytic acid, tannic acid, and hydrochloric acid were used as different doping agents. The identification of polyaniline nanofibers doped with different dopants was done by using FTIR tests. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were used to check the anti-corrosion efficiency of the coatings. Finally, the extraction test was used to directly check the corrosion inhibition effect of the prepared doped polyanilines. The results obtained from the electrochemical impedance test showed that the electrochemical impedance modulus for the coating containing polyaniline doped with phytic acid was in the range of 9.2 to 10.5 Ω.cm², and its phase angle was closer to 90 degrees,thus indicating superior anti-corrosion performance compared to three other coatings. According to the information obtained from the Nyquist diagrams, it was observed that polyaniline doped with phytic acid, tannic acid, and hydrochloric acid, respectively, had the highest arc diameter of the capacitive ring, indicating the formation of a thicker protective layer and thus providing better anti-corrosion performance. This improvement in anti-corrosion performance by phytic acid was attributed to the formation of a stronger complex between metal and phytic acid, which prevented the penetration of corrosive agents to the surface of the underlying metal. The information obtained from the extraction test also confirmed the superior anti-corrosion efficiency of polyaniline doped with phytic acid compared to polyaniline doped with the two other dopant agents. Additionally, the contact angle test was conducted to check the hydrophobicity of the prepared coatings. The epoxy coating containing polyaniline doped with phytic acid showed the highest corrosion resistance among the samples due to the creation of a strong protective layer and increased hydrophobicity with a contact angle of 80°. The results obtained from the review of these findings will significantly contribute to the development of more efficient and sustainable corrosion protection materials.

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