Synthesis of pH-responsive hybrid capsules by Pickering emulsion polymerization and their controlled release properties

pH-Responsive hybrid capsules(PRHCs) have been prepared using an inverse Pickering emulsion polymerization route.An aqueous solution of α-methyl methacrylate was emulsified into an oil phase by sonication to obtain a water-in-oil(W/O) Pickering emulsion stabilized by modified silica nanoparticles.The emulsion was then polymerized to obtain the hybrid capsules.The sizes of the capsules were about 10 μm and the thickness of the wall was 1 μm.The capsule walls consisted of two layers—a solid particle layer and a polymer layer.Controlled release experiments with hybrid capsules containing Rhodamine B showed that the as-synthesized capsules exhibited good pH-responsive properties.After 36h in alkaline and acidic media,the percentage release of Rhodamine B from PRHCs was 15.0% and 98.4%,respectively.