Assembly of magnetic nanoparticles into higher structures on patterned magnetic beads under the influence of magnetic field

The self-assembly of nanoparticles into higher organizations in a controlled manner has critical importance for the utility of the unique properties of nanoparticles. The behavior of magnetic Fe3O4 nanoparticles (MNPs) with an average size of 6 nm under an enhanced magnetic force is reported. Upon evaporation of the solvent where the MNPs are suspended, formation of unique micrometer-sized structures is achieved only when there is a patterned surface constructed from sub-micrometer size magnetic beads in between the applied magnetic field and the MNPs. The preliminary results indicate that the combined effect of magnetic field and evaporation rate might help the control of nanoparticle behavior on surfaces and interfaces in constructing higher structures.