Influence of Surface-Active Component on the Interfacial Dilational Properties of Asymmetrical Anionic Gemini Surfactant C₁₂CO₂Na-p-C₉SO₃Na

Abstract

The influence of two surface-active components, oleic acid and octadecanol, on the interfacial dilational viscoelasticity of an oil-water interfacial layer containing asymmetrical anionic gemini surfactant C₁₂COONa-p-C₉SO₃Na has been investigated. The results show that surface-active component concentration is an important factor in controlling the dilational properties of mixed-adsorption layer. A small quantity of surface-active component may enhance the dilational modulus by forming densely packed mixed-adsorption layer through hydrophobic interaction, while the superfluous addition of surface-active components could sharply decrease the dilational modulus mainly due to the weakening of the crosslink and entanglement among long alkyl chains in surfactant molecules.

Keywords:

• Dilational modulus
• dilational phase angle
• Gemini surfactant C₁₂COONa-p-C₉SO₃Na
• interface
• octadecanol
• oleci acid