There is a great need for approaches to assemble nanoparticles in three dimensions and to preserve the assembled structure. We report a template-free approach for the magnetic field directed self-assembly of chains of 25 nm magnetite nanoparticles in a bulk polymer. Application of a uniform 10 kOe magnetic field drives chain formation within liquid monomers. Heating initiates polymerization of the monomers, resulting in magnetic nanoparticle chains embedded in a solid polymer. Repulsive forces between the chains cause them to assemble into an array with quasiperiodic, micron-scale spacing. According to electron microscopy, the chains remain assembled within the polymer indefinitely after removing the magnetic field. The chains exhibit enhanced magnetic anisotropy along the chain axis. This approach of magnetic field-directed self-assembly is potentially scalable to large volumes, limited only by the size of the electromagnet.

Magnetic field-directed self-assembly of magnetic nanoparticle chains in bulk polymers

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.