Foam Destabilization Effect of Sodium Bis(2-ethylhexyl)sulfosuccinate on Sodium Alkylsulfate Aqueous Solutions Based on Its Fast Surface Tension Gradient Relaxation

This study investigated the relationship between the air–water interfacial dilational viscoelasticity and foam properties in mixed anionic surfactant aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOT), sodium n-dodecylsulfate (C12AS), sodium n-tetradecylsulfate (C14AS), and sodium n-hexadecylsulfate (C16AS). The surfactants used here differ only in hydrophobic chains. The air–water interfacial viscoelasticity of AOT aqueous solutions mixed with C12AS or C14AS was similar to that of AOT single aqueous solutions at the same constituent concentration of AOT. On the other hand, the air–water interfacial viscoelasticity of mixed aqueous solutions of AOT and C16AS was intermediate between the respective single aqueous solutions. The foam properties of these mixed aqueous solutions were evaluated by a modified Ross–Miles method and it was shown that foam stability is correlated with the maximum value of viscoelastic modulus in mixed aqueous solutions of AOT and AS.