Synthesis and properties of sodium isotridecyl polyoxyethylene ether sulfate with different ethylene oxide addition numbers

Abstract

Sodium isotridecyl polyoxyethylene ether sulfate (iC₁₃EO_nS, n = 5, 7, and 9) with different ethylene oxide (EO) numbers were synthesized by SO₃ membrane sulfation process for the first time. The effects of EO number on the equilibrium surface tension, dynamic surface tension, contact angle, and alkali/salt resistance of iC₁₃EO_nS were investigated. With the increase of EO consumption, γ_cmc increased, but the adsorption efficiency (pC₂₀) of surfactant increased. The increase of EO number significantly improved the alkali resistance and salt resistance of iC₁₃EO_nS. Additionally, the influence of different electrolytes and their concentrations on the IFT between iC_l3EO_nS solution and n-decane was also studied. At the same salt concentration, iC₁₃EO_nS with shorter EO chains exhibited lower interfacial tension. These results show that the performance of the product can be adjusted by changing the number of EO groups. The study on the relationship between EO number and the performance of iC₁₃EO_nS in this article will help to improve the application efficiency of this surfactant.

Graphical Abstract

Keywords:

• Sodium isotridecyl polyoxyethylene ether sulfate
• ethylene oxide
• surface properties
• adsorption performance
• interfacial tension

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.