Dispersion of Carbon Nanotubes in Aqueous Solution with Cationic Surfactant CTAB

Stable homogeneous dispersions of carbon nanotubes were prepared by using cetyl trimethyl ammonium bromide(CTAB)as dispersant.Surface chemistry of the carbon nanotube was investigated by measuring isotherm adsorption and Zeta potential.The stabilization mechanism of the carbon nanotubes in aqueous solution of surfactant CTAB was discussed.In the CTAB solutions,the Zeta- potential of carbon nanotube surface progressively increases with increasing the CTAB concentration, in which the Zeta potential of carbon nanotube changes from-29mV to 65mV.The isotherms of CTAB adsorption on carbon nanotubes indicate a two-step mechanism of adsorption,and the isotherms reach the saturation plateau at CTAB concentration of about 9×10~(-4)mol·L~(-1).The optimum concentration of CTAB to obtain a stable homogeneous dispersions of carbon nanotubes is about 9×10~(-4)mol·L~(-1).