Cresol red as corrosion inhibitor in chitosan thin layers on zinc

Chitosan (Chit) is a biopolymer which is synthesized by the deacetylation of chitin extracted from the shells of crustaceans. In the past few years, chitosan was widely used in physical and electrochemical research due to its cost- efficiency, low toxicity and eco- friendly nature [1]. The corrosion inhibition potential of chitosan is due to the amino and hydroxyl groups present in the polymer structure. Chitosan can provide a possible temporary coating on several metal layers [2-3]. Cresol red (CR) is a widely used pH indicator, yellow at pH below 7.2 and purple color at pH higher than 8.8 (in the pH range between 7.2 and 8.8 is red) [4]. This study focuses on the influence of cresol red as a possible corrosion inhibitor for chitosan thin layers on zinc substrates. The chitosan-cresol red system was applied on zinc substrates using dip-coating method. The electrochemical measurements were carried out in a three- electrode cell system using a PARSTAT-2273 single channel potentiostat. Electrochemical impedance spectroscopy was used to investigate the protective properties of the impregnated coatings.

[1] R.C. Cheung et al./ Mar. drugs 13 (8) (2015) 5156– 5186

[2] F. Szoke et al. / International Journal of Biological Macromolecules 142 (2020) 423–431

[3] F. Szoke et al./ Carbohydrate Polymers Volume 215 (2019) 63-72

[4] I. Sousa et al./ Macromol. Mater. Eng. 305 (2020) 1900662