Ordered ferrofluidic assemblies in polymer film formed by magnetically induced polymer-solvent phase separation

Tri-block copolymer has been used as nonferrofluid to generate permanent magnetic structures with controlled dimension and architecture in a partially miscible ferrofluid-nonferrofluid mixture under the influence of a perpendicular magnetic field. The nature of the resultant assemblies was strongly dependent on the magnetic field and concentration of ferro/nonferrofluidic systems. These ordered cluster assemblies in a polymer film that can be used either directly, in applications such as membrane, or subsequently as a template for the formation of other nanostructured materials. The origin of the permanent structures, which have characteristic lateral dimensions ranging from 5 $\mu$m to submicron range, is the repartitioning of the ferrofluid carrier solvent into the nonferrofluid polymeric phase.