Fabrication PDA-polyurea microcapsules with anti-photolysis and sustained-release performances via Pickering emulsion template

In this study, the pyraclostrobin@polydopamine-polyurea microcapsules (Pyr@PNPMC) with anti-photolysis and sustained-release properties were prepared by interfacial polymerization based on O/W Pickering emulsion templates. The effects of water–oil ratio, stirring speed, temperature, and polydopamine nanoparticles (PDANPs) content on the preparation of microcapsules were systematically investigated. Under this condition, the encapsulation efficiency of microcapsules could reach up to 77.7%. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) images indicated that Pyr@PNPMC were prepared successfully, and the microcapsules were a regular sphere with a large number of PDANPs attached to the dense inner layer. According to the results of sustained-release and anti-photolysis experiments, the release rate of Pyr@PNPMC was slightly faster than that of the pyraclostrobin@polyurea microcapsules (Pyr@MC). Under UV light exposure for 7 h, Pyr@PNPMC still retains 83% of the active ingredient, while for Pyr@MC nearly 75% of the active ingredient had been lost.