Development of self-healing coatings with micro capsules for corrosion protection of metal

Self-healing coatings with capsules containing healing agents have been developed for the corrosion protection of metal. In this paper, polyurethane capsules were synthesized under different conditions to examine the size and shape of capsules, and selfhealing ability of coatings with capsules dispersed was examined after damaging the coated layer by scratching with a cutter blade. The size and shape of capsules depended on the concentration of chlorobenzene in cyclohexanone used as a solvent of prepolymer solution. The capsule formed with 70 % of chlorobenzene gave a self-healing capability to the coated layer by releasing the healing agent after damaging. The amount of glycerol added for the formation of the polyurethane capsule shell affected the self-healing ability of the coated layer. The coating with the capsule formed with small amounts of glycerol showed a high healing ability, while, with large amounts of glycerol, the selfhealing ability was relatively low.