Organic-Inorganic Hybrid Microcapsules Fabricated by Pickering Emulsion Templates

The Pickering oil-in-water emulsion stabilized by silicon dioxide (SiO2) nanoparticles was used as a template to fabricate novel microcapsules. The shell of this microcapsule was polyurea (PU), which was achieved by the oil-water interfacial polymerization between polypropylene glycol-toluene diisocyanate (PPG-TDI) and diethylenetriamine (DETA). Ethyl phenylacetate (EPA)-isophorone diisocyanate (IPDI) was successfully encapsulated into the microcapsule. It was found the size and distribution of composite microcapsules could be tailored by altering the volume ratio of water and oil. Optical microscope images exhibited that the diameters of composite microcapsules were in a range of 20 to 90 mu m. From thermal gravimetric analysis (TGA), the encapsulation mass of EPA-IPDI was estimated to be 53 wt%. Scanning electron microscopy (SEM) observation indicated that the capsules had a smooth surface and a uniform thickness of ca. 2 mu m.