摘要
Microcapsules of two different sizes containing UV- and sunlight-curable glue as core material are synthesized. When an epoxy-related coating embedded with the synthesized microcapsules is damaged, the microcapsules release glue that solidifies under sunlight or UV irradiation to restore the epoxy matrix and protect the underlying metal. The larger microcapsules are 25 μm in size with a shell thickness of 200 nm, while the smaller ones are 10 μm in size with 80-nm shells. In theoretical, both microcapsules have high capacity of 97–98% for loading the core material. Self-healing experiment shows that the smaller microcapsules are more efficient than the larger ones to restore scratches in the commercial epoxy. For applications, the better restoration efficiency of the smaller microcapsules also provide better corrosion protection to low-carbon steel under the epoxy coating against salt water. This is further confirmed by electrochemical analysis, which shows a lower corrosion current and a higher polarization resistance when using the smaller microcapsules.