Fabrication and characterization of hierarchical microcapsules with multi-storage cells for repeatable self-healing

Microcapsule-based self-healing polymer has been demonstrated its potential application in various aspects, because their automatically repairing property endows the material with a longer lifetime. However, the limited number of healing times restricts the development of microcapsule-based self-healing system. Herein, a hierarchical microcapsule with multi-storage cells (HMMC) was designed and fabricated by an efficient in-situ polymerization strategy, which could repeatable release active agents to repair cracks in the same region. In this strategy, synthesis microcapsule-type stabilizers (MTS) with healing agent (dicyclopentadiene, DCPD) were used as stabilizers of Pickering emulsion to prepare HMMC by thiol-isocyanate click reaction. It was shown that HMMC exhibited a hierarchical structure with a central capsule covered by a layer of MTS. Thermogravimetric analysis (TGA) showed the core content of HMMCs was 51.52 %. Nuclear magnetic resonance (NMR) spectra and Fourier transform infrared (FTIR) spectra proved that the active DCPD was successfully encapsulated in each storage cells of HMMCs. The repeatable self-healing property was demonstrated by Electrochemical (EIS) and anticorrosion experiments.