One-pot efficient preparation of microcapsules based on photopolymerization for self-healing coatings

Abstract

Self-healing microcapsules are currently one of the most promising functional materials due to their excellent performance. The preparation of self-healing microcapsules via photopolymerization is quite attractive considering its efficiency and environmental-friendliness. However, the influence of the preparation process and shell-formation materials on the formation and the morphology of microcapsule have not been systematically researched. This work combines photopolymerization technology and solvent evaporation to prepare microcapsule, and comprehensively explores the influence of process conditions and shell-formation materials on the microcapsules. Two preparation processes, UV-SR (photopolymerization first and then solvent removal) and SR-UV (solvent removal first and then photopolymerization), have been employed to prepare microcapsules. The SR-UV method is more suitable for preparing microcapsules with high core content and spherical core-shell morphology. The particle size distribution of microcapsules is related to the shear strength during initial emulsion preparation, and the size of microcapsules can be effectively controlled. At the same time, the effect of the shell-formation materials is also systematically studied. The method is universal for the preparation of microcapsules based on commercial UV-curable prepolymers, but the introduction of UV-curable monomers may lead to the transformation of microcapsules from core-shell structure to multi-core structure. Microcapsules can be uniformly dispersed in water-borne epoxy, and the coating based on microcapsules exhibits excellent self-healing properties.