TiO2 Nanocontainers Coconstructed Using Polymers and Corrosion Inhibitors for Anticorrosion Reinforcement of Waterborne Epoxy Coatings

Yijie Jin; Haitao Duan; Shengpeng Zhan; Jiesong Tu; Tian Yang; Wulin Zhang; Lixin Ma; Hualong Yu; Dan Jia

doi:10.1021/acsami.3c12194

TiO₂ Nanocontainers Coconstructed Using Polymers and Corrosion Inhibitors for Anticorrosion Reinforcement of Waterborne Epoxy Coatings

ACS Appl Mater Interfaces. 2023 Nov 15;15(45):52971-52983. doi: 10.1021/acsami.3c12194. Epub 2023 Nov 1.

Authors

Yijie Jin^{1

2}, Haitao Duan^{1

2}, Shengpeng Zhan^{1

2}, Jiesong Tu^{1

2}, Tian Yang^{1

2}, Wulin Zhang^{1

2}, Lixin Ma^{1

2}, Hualong Yu^{1

2}, Dan Jia^{1

2}

Affiliations

¹ State Key Laboratory of Special Surface Protection Materials and Application Technology, Wuhan Research Institute of Materials Protection, Wuhan 430030, China.
² Hubei Longzhong Laboratory, Xiangyang 441000, China.

PMID: 38104278
DOI: 10.1021/acsami.3c12194

Abstract

Stimulus-responsive coatings can provide active corrosion protection in response to environmental changes, but they have not reached their anticipated application prospects because of the intricate preparation processes of hollow materials and methods for loading corrosion inhibitors. Herein, polyaniline molybdate corrosion inhibitor and polydopamine-wrapped titanium dioxide nanocontainers (named TiO₂/PANI-MoO₄^2-/PDA) are synthesized via a simple three-step electrostatic assembly technique. Introducing TiO₂/PANI-MoO₄^2-/PDA nanocontainers in smart waterborne epoxy (WEP) coatings affords the latter with high barriers and long-term corrosion protection. The successful deposition of each layer on the TiO₂ nanocontainer surface was validated via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Release test results show that the molybdate corrosion inhibitor exhibits notable pH-responsive activity under acidic conditions and slow release in neutral environments, which improves the corrosion resistance of coatings. The addition of synthetic nanocontainers greatly improves the impermeability of WEP coatings. The charge transfer resistance of WEP/TiO₂/PANI-MoO₄^2-/PDA coatings is 1.79 × 10¹¹ Ω cm² after 30 day immersion in a 3.5 wt % NaCl solution, which is 3.32 × 10⁵ times higher than that of WEP coatings. WEP/TiO₂/PANI-MoO₄^2-/PDA coatings remain uniform and reliable, even after 50 days of salt spray exposure. The excellent corrosion protection of WEP/TiO₂/PANI-MoO₄^2-/PDA coatings is attributed to (1) the enhanced dispersion and compatibility of PDA in the coating for nanocontainers, (2) the combination of phenolic hydroxyl groups of PDA and Fe, which inhibit corrosion activity on the exposed metal surface, and (3) the on-demand release of the MoO₄^2- inhibitor, which provides sustained passivation protection. This work proposes a strategy to simplify the preparation of responsive long-term anticorrosion coatings and extend their service lives.

Keywords: anticorrosion; electrostatic assembly technique; nanocontainers; titanium dioxide; waterborne epoxy coatings.