Abstract: Synergistic effect of bis-quaternary ammonium salt Gemini surfactant blended separately with sodium dodecylbenzene sulfonate (SDBS) and sodium dodecane sulfonate (SDS) were investigated by fluorospectrophotometry and Zeta potential method.Results showed that the longer the hydrophobic chains and the space group of the bis-quaternary ammonium salt Gemini surfactant,the lower the cmc value;while length of the hydrophobic chain displays bigger effect on performance of the surfactant.Addition of bis-quaternary ammonium salt Gemini surfactant can significantly increase the surface activity of anionic surfactants such as SDBS and SDS.When molar ratio of the bis-quaternary ammonium salt Gemini surfactant to SDBS (SDS) is 3∶7,cmc of the blended surfactant achieves the least.Synergistic effect of the bis-quaternary ammonium salt Gemini surfactant with SDS is better than that with SDBS.

Key words: bis-quaternary ammonium salt Gemini surfactant, sodium dodecylbenzene sulfonate, sodium dodecane sulfonate, blend