Effect of surface treatment with potassium persulfate on dispersion stability of multi-walled carbon nanotubes

Muti-walled carbon nanotubes (MWCNTs) were treated with different concentrations of potassium persulfate (KPS; K2S2O8) to improve their dispersion stability, which were characterized by thermal gravimetric analysis, ultraviolet/visible spectroscopy, field emission scanning electron microscopy and field emission transmission electron microscopy. The amount of sulfate groups on the MWCNTs increased with increasing KPS concentration, which enhanced the hydrophilicity, but deteriorated the dispersion stability. The optimal KPS concentration for the best dispersion stability of the KPS-treated MWCNTs was 0.01 M.