Preparation of thermoresponsive Fe3O4/P(acrylic acid–methyl methacrylate–N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein

• Published in: Journal of colloid and interface science Vol. 398; pp. 51 - 58
• Main Authors: Zhang, Baoliang, Zhang, Hepeng, Fan, Xinlong, Li, Xiangjie, Yin, Dezhong, Zhang, Qiuyu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15-05-2013; Elsevier
• Subjects: 1,1-diphenylethene; Acrylamides - chemistry; Acrylates - chemistry; Chemistry; Colloidal state and disperse state; Controlled polymerization; Controlled release; Delayed-Action Preparations - chemistry; Drugs; Exact sciences and technology; Ferric Compounds - chemistry; Fourier transform infrared spectroscopy; General and physical chemistry; Magnetic microspheres; Methylmethacrylate; Microspheres; Monomers; nuclear magnetic resonance spectroscopy; particle size distribution; Phenolphthalein; Phenolphthalein - chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Polymerization; polymers; Radicals; Shells; Thermoresponsive; Thermosensitive; transmission electron microscopy; 1,1-diphenylethene; Controlled polymerization; Thermoresponsive; Controlled release; Magnetic microspheres; Binary compound; Microsphere; Iron oxide; Acrylic acid; Transition element compounds; Temperature effect; Polymerization; Composite material; Thickness; Magnetite; Preparation; Microparticle; Spherical particle; Methyl methacrylate; Release
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2013.01.042

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► Fe3O4/P(AA–MMA–NIPAm) were prepared by controlled radical polymerization. ► Thermosensitive polymer shell thickness of magnetic microspheres can be controlled. ► Controlled release properties improved with increasing of thermosensitive polymer shell. ► Polymerization mechanism and coating process of magnetic microspheres were described.
In this work, Fe3O4/P(acrylic acid–methyl methacrylate–N-isopropylacrylamide) (Fe3O4/P(AA–MMA–NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres.