Effect of alkyl groups in anionic surfactants on solution properties of anionic-nonionic surfactant system

The effect of different alkyl chains of anionic surfactants on properties of binary anionic-nonionic mixed surfactant systems was studied. These systems included octyl-, dodecyl, and cetylsulfoacetates mixed with isooctyl phenol nonyl ethoxylate. The critical micelle concentration of mixed surfactants shifted to lower values compared to those of the single anionic surfactants. Effectiveness values increased with decreases in the mole fraction of anionic surfactants. The negative values of interaction parameter (beta) increased with increases in the chain length of anionic surfactants.