Magnetic assembly and pyrolysis of functional ferromagnetic colloids into one-dimensional carbon nanostructures

A novel synthetic route to functionalize and magnetically assemble ferromagnetic colloids into one-dimensional (1-D) carbon nanostructures is reported. The synthesis of ferromagnetic cobalt nanoparticles with polyacrylonitrile (PAN) shells was achieved by ligand exchange of PAN onto preformed polystyrene-coated ferromagnetic cobalt nanoparticles. PAN-coated ferromagnetic nanoparticles (PAN-CoNPs) were then cast onto supporting surfaces from N,N-dimethylformamide (DMF) in the presence of an external magnetic field and pyrolyzed to form 1-D carbon nanoparticle chains spanning microns in length. Atomic force microscopy, field emission scanning electron microscopy, Raman spectroscopy, vibrating sample magnetometry, and X-ray diffraction were used to confirm the preparation of these 1-D hybrid nanostructures. This versatile methodology provides an alternative approach to prepare 1-D carbon materials using soluble precursors that can be magnetically directed and organized.