Oil‐Based Self‐Healing Barrier Coatings: To Flow and Not to Flow. (9th October 2019)

• Record Type: Journal Article
• Authors: Yu, Zhilong; Lim, Alane T. O.; Kollasch, Shannon L.; Jang, Hee Dong; Huang, Jiaxing
• Is Part Of: Advanced functional materials. Volume 30:Number 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-10-09
• Subjects: anti‐fouling -- corrosion control -- local corrosion -- microcapsule‐thickened oil -- self‐healing; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201906273
• Languages: English
• ISSNs: 1616-301X

Abstract

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. Abstract : Microcapsule‐thickened oil has been demonstrated to exhibit length scale dependent viscosity—macroscopically it does not flow and can form a stable coating on metal surface, yet microscopically it readily flows and can self‐heal when being scratched. This example illustrates how contradicting material properties are able to co‐exist in a "smart" material system by accommodating them at different length scales.