Fabrication of Fe3O4 nanoparticle arrays via patterned template assisted self-assembly

Magnetic nanoparticle arrays have been fabricated by combining chemically synthesized Fe3O4 nanoparticles with a diblock copolymer template substrate consisting of self-assembled polystyrene (PS) dots in a polymethylmethacrylate (PMMA) matrix. The influence of the volume fraction of the Fe3O4 suspending solution and the withdrawal speed of the template on the formation of array structures was investigated. A small volume fraction of the nanoparticles and low withdrawal speed play an important role in the fabrication of the patterned arrays of nanoparticles via template assisted self-assembly. Below a withdrawal speed of 0.5 mm s-1 and a nanoparticle volume fraction below 0.05 vol% (in particular, at extremely high dilutions of less than 0.01 vol%), the selective deposition of one to several nanoparticles on every single PS dot becomes possible