Synthesis of pH and UV dual-responsive microcapsules with high loading capacity and their application in self-healing hydrophobic coatings

Multi-stimuli responsive polymer microcapsules are attracting much interest owing to their multiple and tunable functionalities, but it still remains a great challenge to develop facile and cost-efficient strategies for fabrication of these microcapsules. In this study, we report a simple and facile method to synthesize pH and UV dual-responsive microcapsules by UV-initiated polymerization of Pickering emulsions stabilized with SiO2 and TiO2 nanoparticles. Because the UV-initiated polymerization is gentle and fast, the as-obtained microcapsules can encapsulate as high as 30 wt% of a hydrophobic compound based on the total mass of the capsules. When these microcapsules are used in waterborne coatings, these coatings exhibit not only quick responses to pH and UV stimuli, but also very good self-repairing performance.