The Ultraviolet-Induced Functionalization of Multi-Walled Carbon Nanotubes with Polymer Radicals Generated from Polyvinyl Benzoate Derivatives

In order to develop a novel technique for the fabrication of hybrid materials containing polymers and nanocarbons, we examined the surface modification of pristine multi-walled carbon nanotubes (MWCNTs) with benzyl-type polymer side chain radicals generated through photolysis of 4-(chloromethyl) benzoate moieties. The polymer with a 4-(chloromethyl) benzoate side chain was prepared by the esterification of polyvinyl alcohol (PVA) with corresponding acid chloride. The synthesized polymer and MWCNTs were mixed in N-methylpyrrolidone and irradiated with ultraviolet (UV) light. Structural changes of the polymer and MWCNTs were observed by means of X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The XPS results revealed that scission of the C-Cl bonds of the chloromethyl groups and benzyl-type radical formation occurred. The incremental surface defects of the MWCNTs caused by UV irradiation were confirmed by means of Raman spectroscopy. These results support the covalent bond formation between the polymer side chain and MWCNT sidewalls by radical addition reaction. The photothermal conversion characteristics of the prepared materials were also evaluated.