Self-healing coatings for large-scale damages via ultrahigh load capacity of healing agents in short Kapok microtubules

Self-healing materials, due to their ability to autonomously repair damages, have been extensively applied in the field of metal corrosion protection. However, prior self-healing coatings are powerless against large-scale damages limited by their relatively low amounts of prestored self-healing agents in microcontainers, which severely restricts their long-term anticorrosion performance. Herein, to address this issue, we propose a simple strategy to prestore a water-soluble cerium-based corrosion inhibitor, cerium gluconate, into Kapok fibers through a cyclic process of vacuum drying after saturation with the inhibitor solution, and the load capacity of cerium gluconate in Kapok (CG@K) by this approach can reach up to 455wt%. This new loading system is relatively easy to be carried out while give an ultrahigh load capacity, and applicable to encapsulate other healing agents theoretically. The Kapok fibers embedded uniformly in the self-healing coatings exhibit a dense three-dimensional network structure, which, along with the ultra-high loading content, renders the self-healing coatings distinguished corrosion resistance. It is worth noting that the self-healing coatings achieve a remarkable ability to autonomously repair large-scale cracks up to 400 μm. This work provides an option for fabricating high agent load capacity and shows tremendous potential for designing self-healing coatings for large-scale damages.