The formation of magnetite nanoparticles on the sidewalls of multi-walled carbon nanotubes

Linear polyethyleneimine (PEI) was used as a non-covalent functionalizing agent to modify multi-walled carbon nanotubes (MWCNTs). Fe3O4 nanoparticles were then formed along the sidewalls of the as-modified MWCNTs through a simple solvothermal method. X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, and vibrating sample magnetometry were used to characterize the MWCNT/Fe3O4 nanocomposites. Results indicated that Fe3O4 nanoparticles with diameters ranging from 50 to 200 nm were attached to the surface of the MWCNTs by electrostatic interaction. PEI was found to improve the electrical conductivity of the MWCNT/Fe3O4 nanocomposites. The magnetic saturation value of these magnetic nanocomposites was 61.8 emu g−1. These magnetic MWCNT/Fe3O4 nanocomposites are expected to have wide applications in bionanoscience and technology.