Preparation of pH-responsive Fe3O4/Poly (acrylic acid-stat-methyl methacrylate-block-(2-dimethylamino) ethyl methacrylate) magnetic composite microspheres and its application in controlled release of drug

Controlled radical polymerization based on 1, 1-diphenylethylene (DPE method) was used to prepare pH-responsive magnetic composite microspheres. By this method, Fe3O4/Poly (acrylic acid-stat-methyl methacrylate-block-(2-dimethylamino) ethyl methacrylate) (Fe3O4/P(AA-MMA-DMA)) microspheres were prepared via emulsifier free emulsion polymerization of acrylic acid (AA), methyl methacrylate (MMA) and (2-dimethylamino) ethyl methacrylate (DMA) using 1, 1-diphenylethylene (DPE) as radical control agent in the presence of Fe3O4 nanoparticles. The structure and properties of Fe3O4/P (AA-MMA-DMA) microspheres were characterized by IR, 1H NMR, SEC-MALLS, TEM, TGA, VSM and DLS. The application of Fe3O4/P (AA-MMA-DMA) microspheres in controlled release of drug was also investigated. It was found that the DPE method allowed the preparation of pH-responsive magnetic composite microspheres, and Fe3O4/P (AA-MMA-DMA) microspheres obtained were pH-responsive, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 14.36 emu/g, and high magnetic content with a value of 29%. Moreover, Fe3O4/P (AA-MMA-DMA) microspheres could control the release of phenolphthalein in a buffer solution by adjusting the pH value.