A Study on Dispersion and Antibacterial Activity of Functionalizing Multi-walled Carbon Nanotubes with Mixed Surfactant

The dispersibility in aqueous phase and antibacterial activity of multi-walled carbon nanotubes (MWNT) with mixed surfactant functionalization has been studied. The ratio of 3:7 between hexadecyltrimethylammonium bromide and octylphenol ethoxylate (TX100) showed the highest dispersing power for MWNT. The use of mixed surfactants formed stable MWNT dispersions at lower total surfactant concentration compared to their concentrations when used alone. UV-Vis spectroscopy, transmission electron microscopy and Fourier transform infrared spectroscopy were employed to characterize the dispersion of MWNT in the aqueous phase. The result indicated that the surfactant molecules had been successfully adsorbed onto the surface of the MWNT. Bacterial toxicity assay showed that the mixed surfactant-functionalized MWNT had a strong antibacterial activity and concentration dependence to Staphylococcus aureus. Based on the consideration of the cost and environmental impact, the use of mixed surfactant (CTAB-TX100) should be more favorable for the stable dispersion of MWNT and the improvement of antibacterial activity than that of an individual surfactant. These observations suggested that the mixed surfactant-functionalized MWNT might be a promising antibacterial agent for removal and inactivation of biological contaminants in water treatment applications.