Abstract: Equilibrium surface tension and dynamic surface tension of four kinds of sugar-based Gemini cationic surfactant (SGCS) were determined with Wilhelmy method and maximum bubble pressure method;and the surface activity of SGCS was evaluated.Value of γ_cmc of SGCS is about 30 mN/m and cmc is in order of magnitude of 10^-4 mol/L,which is 1-2 order of magnitude lower than that of conventional cationic surfactants.It showed that SGCS has excellent surface activity.There are linear relationship between lg c_cmc and carbon number of the hydrophobic group,as well as pc₂₀ and carbon number of the hydrophobic group.Following the increasing of concentration of SGCS and temperature,the decreasing rate of the dynamic surface tension rises rapidly.It showed that the higher the temperature,the stronger the dynamic surface activity of SGCS.

Key words: sugar-based surfactant, Gemini surfactant, cationic, surface tension