Rapid surface functionalization of iron-filled multi-walled carbon nanotubes

Iron-filled multi-walled carbon nanotubes (Fe@MWCNTs) were surface functionalized with various functionalities via a rapid, single-step process involving ultrasonication assisted and microwave-induced radical polymerization reactions. Both hydrophobic (e.g., polystyrenes and polymethyl methacrylate) and hydrophilic (e.g., polyacrylamide, polyacrylic acids, and polyallyl alcohols) polymer chains can be chemically grafted onto the surface of MWCNTs by the same process within ∼10 min. The surface grafted polymers were identified by FTIR, TGA, TEM, EELS and Raman spectra. The solubilities of the surface derivatized MWCNTs are in the range of 1200–2800 mg/l in solutions. The polyacrylic acids modified iron filled MWCNTs have a saturated magnetic dipole moment of ∼40 emu/g at room temperature with a coerceive field of nearly zero gauss.