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Hydrophilic dual-responsive magnetite/PMAA core/shell microspheres with high magnetic susceptibility and ph sensitivity via distillation-precipitation polymerization

Authors

  • Wanfu Ma,

    1. Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
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  • Shuai Xu,

    1. Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
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  • Jumei Li,

    1. Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
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  • Jia Guo,

    1. Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
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  • Yao Lin,

    1. Polymer Program, Institute of Materials Science & Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269
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  • Changchun Wang

    Corresponding author
    1. Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
    • Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, and Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China
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Abstract

A facile and effective approach to preparation of dual-responsive magnetic core/shell composite microspheres is reported. The magnetite(Fe3O4)/poly(methacrylic acid) (PMAA) composite microspheres were synthesized through encapsulating γ-methacryloxypropyltrimethoxysilane (MPS)-modified magnetite colloid nanocrystal clusters (MCNCs) with crosslinked PMAA shell. First, the 200-nm-sized MCNCs were fabricated through solvothermal reaction, and then the MCNCs were modified with MPS to form active vinyl groups on the surface of MCNCs, and finally, a pH-responsive shell of PMAA was coated onto the surface of MCNCs by distillation-precipitation polymerization. The transmission electron microscopy (TEM) and vibrating sample magnetometer characterization showed that the obtained composite microspheres had well-defined core/shell structure and high saturation magnetization value (35 emu/g). The experimental results indicated that the thickness and degree of crosslinking of PMAA shell could be well-controlled. The pH-induced change in size exhibited by the core/shell microspheres reflected the PMAA shell contained large amount of carboxyl groups. The carboxyl groups and high saturation magnetization make these microspheres have a great potential in biomolecule separation and drug carriers. Moreover, we also demonstrated that other magnetic polymeric microspheres, such as Fe3O4/PAA, Fe3O4/PAM, and Fe3O4/PNIPAM, could be synthesized by this approach. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.

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