Surface modification of carbon nanotubes with ethylene glycol plasma

Multi-walled carbon nanotubes (MWCNTs) were modified using plasma polymerization with ethylene glycol (EG) as monomer. Conditions of the EG plasma process in a specially designed reactor and the plasma-polymerized ethylene glycol (PPEG) coating were studied. The study involved varying the plasma powers of 10 and 20 W at a constant process time of 60 min, and EG flow rate of 0.15 cm3/min. Dispersion of the modified MWCNTs was evaluated in several solvents, showing hydrophilic behavior. Morphology of the PPEG coating and the functional groups (hydroxyl) on its surface were characterized by both transmission electron microscope and FTIR spectroscopy. Characterization by thermogravimetric analysis and FTIR suggested that the hydroxyl groups of the PPEG coating residing inside the nanotubes possessed higher thermal stability than the ones outside.