Pickering乳液聚合法制备pH敏感复合微胶囊及其缓释性能

利用反相Pickering乳液聚合法制备了聚α-甲基丙烯酸/二氧化硅复合微胶囊。以改性纳米二氧化硅为稳定剂，以液体石蜡作为油相，以α-甲基丙烯酸的水溶液作为水相，经超声乳化，可得到水/油型的Pickering乳液。再经过聚合，即可得到复合微胶囊。微胶囊的平均粒径约为10μm，胶囊壁由二氧化硅颗粒层和聚合物层两部分组成，壁厚约为1μm。以罗丹明B为缓释试剂研究了微胶囊的可控缓释性能，研究结果表明复合微胶囊具有良好的pH敏感性，在碱性体系中罗丹明B的释放量为15.0%，在酸性体系中罗丹明B释放量提高至98.4%。

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.