A self-healing polymer composition 10 contains a polymer media 12 and a plurality of microcapsules of flowable polymerizable material 16 dispersed in the polymer media 12, where the microcapsules of flowable polymerizable material 16 contain a flowable polymerizable material 15 and have an outer surface 142 upon which at least one polymerization agent 13 is chemically attached. The microcapsules 16 are effective for rupturing with a failure of the polymeric media 12, and the flowable polymerizable material 15 reacts with the polymerization agent 13 when the polymerizable material 15 makes contact with the polymerization agent 13 upon rupture of the microcapsules 14. There is also provided a method of using the self-healing polymeric composition 10 to repair fractures in polymers, as well as articles of manufacture including the self-healing system, and the microencapsulated polymerizable particles 16 themselves.