Synthesis and characterization of magnetic nanoparticle/block copolymer composites.

A simple strategy to improve the particle dispersion and structural ordering of magnetic nanoparticle/block copolymer composites is demonstrated. This method consists of manipulating both the block copolymer structure in a solvent and the relative interactions of particle/solvent and polymer/solvent to facilitate the self-assembly of particles in the preferred domain of the block copolymer. In a neutral solvent, the freely expanded structure of the polymer and the slightly weaker affinity between particle and solvent than between particle and polymer promotes the selection of particles in the preferred domain of the block copolymer. Furthermore, more particles are allowed to be incorporated into the polymer matrix while still obtaining the nicely ordered structure when these particles exhibit smaller magnetization.