Smart coatings embedded with polydopamine-decorated layer-by-layer assembled SnO2 nanocontainers for the corrosion protection of 304 stainless steels

Zhihao Chen; Wenzhong Yang; Yun Chen; Xiaoshuang Yin; Ying Liu

doi:10.1016/j.jcis.2020.06.118

Smart coatings embedded with polydopamine-decorated layer-by-layer assembled SnO₂ nanocontainers for the corrosion protection of 304 stainless steels

J Colloid Interface Sci. 2020 Nov 1:579:741-753. doi: 10.1016/j.jcis.2020.06.118. Epub 2020 Jul 5.

Authors

Zhihao Chen¹, Wenzhong Yang², Yun Chen¹, Xiaoshuang Yin¹, Ying Liu¹

Affiliations

¹ School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009, China.
² School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009, China. Electronic address: yangwznjtech@163.com.

PMID: 32673851
DOI: 10.1016/j.jcis.2020.06.118

Abstract

Polydopamine (PDA), which is a mussel-inspired synthetic polymer, is widely used in surface modification field because of the high potential of the dopamine functional groups. Herein, we develop an SnO₂ nanocontainer and deposit polypyrrole (PPy), molybdate corrosion inhibitors and PDA layers using the layer-by-layer self-assembly technology. Then, the SnO₂ nanocontainer were incorporated into the epoxy coating to improve their corrosion resistance and self-healing ability and realize the active corrosion protection of stainless steels. The XRD, FTIR, TGA and Zeta potential results confirm the deposition of each layer on the surface of the SnO₂ nanocontainer. The FESEM and HRTEM images confirm the formation of the core-shell structures on the SnO₂ nanocontainers. The ICP-MS test indicates the slow-release tendency of the encapsulated molybdate corrosion inhibitors the in neutral environments. Further, the corrosion behaviors of the epoxy-based coatings with/without 10 wt% SnO₂ nanocontainers are evaluated using electrochemical tests in 3.5 wt% NaCl solution. Results suggest that epoxy coatings with PDA-decorated SnO₂ nanocontainers exhibit a high corrosion resistance and an excellent self-healing performance. The enhanced anti-corrosion and self-healing properties of the epoxy coatings can be attributed to the deposited PDA layer on the SnO₂ nanocontainer, which serves as a pH-sensitive gatekeeper that can control the on-demand release of the molybdate corrosion inhibitor and promote the reformation of the cracked polymer networks using the dopamine functional groups and iron oxide. Furthermore, various OH groups provided by PDA facilitates the dispersion of the SnO₂ nanocontainers in epoxy coatings. The application of multi-functional dopamine-based gatekeepers will allow more applications with respect to multi-functional intelligent anti-corrosive coating formulations.

Keywords: Corrosion; Dopamine; Epoxy coating; Layer-by-layer; Self-healing; pH-sensitive nanocontainer.