Localized corrosion involves the selective attack of a metal at a small, exposed site. This can be particularly devastating for load-bearing structures like bridges, which can fail catastrophically even with very little material loss. Unfortunately, such corrosion is very hard to prevent, predict, and detect. Corrosion can be prevented by barrier coatings, which isolate metal from reactive environments. However, pinholes and other minor damage to the coating expose small areas of metal and can eventually lead to localized corrosion. An example can be found with the two-dimensional material graphene, which has been highlighted as a potential anti-corrosion material due to its impermeability to moisture and molecules. Contrary to this expectation, a graphene coating may actually accelerate the degradation of the metal it was intended to protect if it is not free of defects. One strategy for mitigating such corrosion is to design barrier coatings to be self-healing, so that they spontaneously repair themselves when scratched. Our lab has designed a self-healing coating based on the idea that low-viscosity liquids can readily flow and reconnect. Such liquids, however, typically do not form stable coatings on metal surfaces. To address this problem, we have developed anti-corrosive oil coatings that can be stabilized on metal without sacrificing the liquid’s free-flowing properties. By mixing low-viscosity silicone oil with graphene-based microcapsule thickeners to make a coating we call “r-GO/oil,” we can create films that flow when scratched but otherwise remainimmobilized on metal surfaces. These coatings can repeatedly self-heal millimeter-scale scratches, be readily painted onto metal underwater, and protect metal from corrosion for extended periods of time. We also show that these self-healing coatings are not limited to graphene-based microcapsules and silicone oil, but rather is materials agnostic. We demonstrate several coatings that are fabricated using commercially available oils and particles, and discuss further basic science experiments and potential applications.

Creator

• Lim, Alane Tarianna Ocampo

DOI

• https://doi.org/10.21985/n2-y779-jz64

Subject

• Materials Science

Language

• en

Alternate Identifier

• etdadmin_upload_663032
• http://dissertations.umi.com/northwestern:14674

Keyword

• liquids
• coatings
• self-healing

Date created

• 2019-01-01

Resource type

• Dissertation

Rights statement

• In Copyright