Fabrication of ultraviolet-responsive microcapsules via Pickering emulsion polymerization using modified nano-silica/nano-titania as Pickering agents

Fluoroalkyl silane (FAS)-loaded polystyrene microcapsules were prepared via Pickering emulsion polymerization using silica/titania nanoparticles as Pickering agents, wherein the nanoparticles were first modified with a Trixton X-100-tethered silane coupling agent. The microcapsules display rugged surfaces and have average sizes from 150 nm to 890 nm, depending on the nanoparticles-to-oil mass ratio. Under UV exposure, the microcapsules break up and release the encapsulated FAS, demonstrating their UV-responsive ability. The microcapsules were further embedded into waterborne coatings. Monitoring the evolution of the surface wettability of the coatings under UV-exposure indicates that the releasing rate of FAS could be tunable using the content of TiO 2 nanoparticles in the microcapsules. UV-responsive microcapsules were prepared via O/W Pickering emulsion templates using SiO 2 and TiO 2 nanoparticles as Pickering agents.