By using the dimensional crystal model and the regular solution theory, the relationship between the super chemical potential of component A(μ^E~m~,~A) and the surfactant molecule-exchanging energy (ε~m) of spherical micelles in binary surfactant aqueous solution, μ^E~m~,~A=ε~m~gN~0(1-x~A)^2, has been firstly established. Then with the help of the micellar separated phase model, the relationship between the parameter of molecule interaction in spherical micelles (β~m), which cabtained from the surface tension vs. the logarithm curves (γ～logc), and the surfactant molecule-exchanging energy, ε~m=gRTβ~m/N~0, has secondly been deduced. By using this equation for practical calculation of ε~m, the synergism of binary surfactant ixtures of gleditsin saponin (GS) (C~3~0H~3~8O~3) with C~1~2H~2~5SO~3Na (AS), C~1~2H~2~5(OC~2H~4)~3SO~4Na (AES), C~7F~1~5CO~2Na (OBS), C~1~6H~3~3NMe~3Br (CTAB), C~8H~1~7Ph(EO)~1~0OH (Tritonx 100) and C~1~2H~2~5(EO)~9OH (AEO~9) in spherical micelles of aqueous solutions has been studied from the view of energy at 25℃. The results show that all the surfactant molecule-exchanging energies of the binary systems of GS in micelles are smaller than zero, which means that GS can produce remarkable synergism when mixed with other surfactants.

Key words: SURFACTANTS, BINARY SYSTEM, MICELLE