Oil‐Based Self‐Healing Barrier Coatings: To Flow and Not to Flow

Abstract

Localized corrosion involves the selective attack of a metal at a small, exposed site. This can be particularly devastating for load‐bearing structures, which can fail catastrophically even with very little material loss. Unfortunately, local corrosion is difficult to prevent, predict, and detect. Corrosion can be prevented by barrier coatings, however, imperfections such as pinholes and scratches, can expose small areas of metal and eventually lead to localized corrosion. Herein, a new strategy for self‐healing, damage‐tolerant coatings that can mitigate localized corrosion is presented. The new self‐healing system consists of microcapsule‐thickened low‐viscosity oil and exhibits length scale‐dependent viscosity. Macroscopically, the coating is viscous due to the formation of a 3D particle network, which allows it to stick to vertical metal surfaces against gravity and turbulent flow. Microscopically, the oil exhibits low viscosity and can rapidly flow to damaged areas to re‐establish the particle network. The coating exhibits remarkable barrier properties and protects metal from corrosion for a long time. Moreover, the coating is able to repeatedly self‐heal over the same area hundreds of times over. The strategy described here illustrates how contradicting material properties (e.g., viscosity) co‐exist in a “smart” material system by accommodating them at different length scales.

Towards Understanding the Corrosion Behavior of Zinc‐Metal Anode in Aqueous Systems: From Fundamentals to Strategies

“…[36][37][38] Zinc electrodes with non-uniform surfaces present different potentials in different regions, so that the galvanic cell corrosion can form on the surface of anodes along with converting chemical energy into electrical energy and deteriorating the battery performance in aqueous electrolyte environments. [30,39,40] The strategies involving chemical polishing have been used to treat the zinc surface and obtain a uniform ridge-like structure, which can optimize the cycling performance of batteries (Figure 2c and d). However, the further exploration of surface modification techniques adapted to commercial production is still needed.…”

“…As zinc is a relatively soft metal, the manufacturing process often leaves various types of surface defects on the final zinc foil surface, which significantly reduces the cycling stability of the zinc foil [36–38] . Zinc electrodes with non‐uniform surfaces present different potentials in different regions, so that the galvanic cell corrosion can form on the surface of anodes along with converting chemical energy into electrical energy and deteriorating the battery performance in aqueous electrolyte environments [30,39,40] . The strategies involving chemical polishing have been used to treat the zinc surface and obtain a uniform ridge‐like structure, which can optimize the cycling performance of batteries (Figure 2c and d).…”

Stabilization of Zn Metal Anode through Surface Reconstruction of a Cerium‐Based Conversion Film

“…In a corrosive medium, the anodic GBs and cathodic grains can form microgalvanic cells, causing preferential corrosion of metal atoms along the boundaries, and such localized corrosion can penetrate metal without much mass loss and initiate small cracks, which may lead to catastrophic failure of metals (Figure 2h). [30] Fortunately, the CCF, which replaces the Zn surface with corrosion-resistant cerium/zinc oxides, can serve as an anticorrosion layer for Zn, especially for GBs on it. It can not only homogenize the current density distribution of the anode, [21] but also effectively isolate Zn metal from H 2 O and O 2 , thus suppressing the dissolution of Zn and hydrogen evolution as well as improving the cycling performance of the batteries, [23] which will be presented in the following parts.…”

Light-driven self-healing polyurethane based on PDA@Ag nanoparticles with improved mechanical and antibacterial properties

“…17,18 When exposed to destruction, self-healing polymer-based coatings can repair their damage autonomously, retain structural integrity, and enhance their longevity and stability. 19,20 To endow the polymer with self-healing capability, various dynamic bonds were introduced into the polymer matrix to construct reversible networks, including reversible chemical bonds and noncovalent interactions. 21 Among them, the Diels-Alder (DA) reaction is a thermally reversible reaction between a dienophile and a conjugated diene that generates a cyclohexene derivative.…”