Web Release Date: January 29,
Design and Synthesis of Novel Magnetic Core-Shell Polymeric Particles
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China
Received September 18, 2007
In Final Form: November 15, 2007
Abstract:
A novel synthetic strategy was developed for the preparation of magnetic core-shell (MCS) particles consisting
of hydrophobic poly(methyl methacrylate) cores with hydrophilic chitosan shells and 
-Fe2O3 nanoparticles inside
the cores via copolymerization of methyl methacrylate from chitosan in the presence of vinyl-coated -Fe2O3 nanoparticles.
The magnetic core-shell particles were characterized with transmission electron microscopy, field-emission scanning
electron microscopy, particle size and 
-potential measurements, vibrating sample magnetometry, and atomic force
microscopy, respectively. The MCS particles were less than 200 nm in diameter with a narrow size distribution
(polydispersity = 1.09) and had a good colloidal stability (critical coagulation concentration = 1.2 M NaCl at pH
6.0). Magnetization study of the particles indicated that they exhibited superparamagnetism at room temperature and
had a saturation magnetization of 2.7 A m2/kg. The MCS particles were able to form a continuous film on a glass
substrate, where magnetic nanoparticles could evenly disperse throughout the film. Thus, these new materials should
be extremely useful in various applications.
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