Abstract:

The surface properties of pentadecyl m-xylene sodium sulfonates synthesized by our laboratory in pure water and 0.0393mol•L-1 isopropanol solution were measured. The measurements indicated that the critical micelle concentration (cmc) , the saturated adsorption area Amin and the negative logarithms of surfactant concentration needed in order to reduce surface tension 20 mN/m (pc20) increased, the standard free energy of adsorption( ) became more negative, the surface tension at the cmc (γcmc) and maximum surface excess at the cmc(Γmax) decreased with the moving of the aryl from the terminal to the center of the long alkyl chain. And with the addition of isopropanol the cmc decreased. The effect of molecular branched structure on surface properties were explained from the view of molecular structure.

Key words: Pentadecyl m-xylene sodium sulfonate, cmc, Saturated adsorption capacity, Surface tension