Nanocomposite Fabrication Through Particle Surface Initiated Polymerization

Magnetic nanoparticles (NPs) have attracted much interest due to their special physicochemical properties such as enhanced magnetic moment and coercivity different from the bulk and atomic counterparts. Incorporation of the inorganic NPs into a polymer matrix has extended the particle applications such as in high-sensitivity chemical gas sensors due to the advantages of polymeric nanocomposites possessing high homogeneity, flexible processability and tunable physicochemical properties such as improved mechanical, magnetic and conductive properties. High particle loading and flexibility are required of nanocomposite for certain applications such as photovoltaic (solar) cells, photodetectors and shape-memory devices. A microwave absorber is another application that can benefit from using magnetic nanoparticles. A typical microwave absorber consists of micron size magnetic fillers in a polymer matrix. To get an optimum absorption, the particle loading in the polymer matrix is about 40% to 60% by volume. However, the challenge of incorporating nanoparticles into polymer is amplified by the difficulty of dispersing a high loading of nanoparticles without sacrificing the mechanical properties of the resulting composite. Current high-particle-loading nanocomposites are normally fabricated by directly mixing the particles with the polymer monomers followed by curing at a certain temperature, or alternatively, using a solvent to disperse the particles followed by casting to produce a thin film. Both methods result in inhomogeneous dispersion and unacceptable mechanical properties. The major challenge is to process a nanocomposite with uniform particle distribution and good properties.