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Oil‐Based Self‐Healing Barrier Coatings: To Flow and Not to Flow
Author(s) -
Yu Zhilong,
Lim Alane T. O.,
Kollasch Shan L.,
Jang Hee Dong,
Huang Jiaxing
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201906273
Subject(s) - materials science , corrosion , coating , viscosity , composite material , particle (ecology) , flow (mathematics) , self healing , flow conditions , metal , nanotechnology , metallurgy , mechanics , medicine , physics , alternative medicine , pathology , oceanography , geology
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.