Self-healing materials have become an important area of research and development over the past decade. The main objective is to develop materials with a built-in ability to autonomously maintain and restore their structural integrity after damage. Self-healing ability should result in longer material life, less maintenance, and hence lower potential costs. Corrosion of metals is a problematic phenomenon that leads to catastrophic damage and deterioration. To prevent this natural process, self-healing anticorrosive coatings are considered as innovative and efficient way. Those multi-component so-called smart materials have been proposed as a long-lasting corrosion protection of steel structures. The currently most promising technological route is based on microcapsules, filled with active healing agents, and is the main target of our work.

In the present study, an anticorrosion vegetable oil was encapsulated in biopolymers-shell microcapsules using an emulsion solvent evaporation method. Two varieties of materials, native biopolymer and phosphorylated biopolymer, were used as shell materials. The chemically modified biopolymer via phosphorylation reaction and the prepared microcapsules were evaluated by optical microscopy, SEM spectroscopy, FTIR spectroscopy, TGA analysis and ICP analysis. Results showed that spherical microcapsules at micrometric scale were obtained. FTIR spectroscopy and TGA analysis were involved to prove the oil presence in microcapsules and to verify the absence of any strong chemical interaction between core and shell materials. Oil content and size distribution of the prepared capsules were caried out for more investigations. An epoxy coating containing the prepared microcapsules has been prepared and applied on mild steel substrate. The corrosion resistance enhancement due to the embedded microcapsules and phosphorus presence was evaluated by salt spray test.