Mixtures of nonionic surfactants made from renewable resources with alkyl sulfates and sodium n-alkanecarboxylates: Comparison of mixing behavior using Rubingh's treatment

Binary aqueous mixtures of (1) alkyl glucopyranosides (glycosides), (2) alkyl maltopyranosides (maltosides), or (3) alkyl N-methyl glucamines with (1′) sodium alkyl sulfates or (2′) sodium n-alkyl carboxylates were investigated in an effort to evaluate physiochemical properties for mixtures of surfactants from renewable resources. Solutions at various concentrations and mixture ratios were tested and evaluated to determine critical micelle concentrations (CMCs). The greatest reduction in CMC was found for surfactants with long and intermediate hydrophobe lengths. In agreement with other studies, an increase in hydrophilic group size and flexibility decreased the electrostatic repulsion of ionic-nonionic mixed micelles as evidenced by a more negative Rubingh's β parameter. However, at low hydrophobe length, carboxylate and glycoside headgroup mixtures produced mixed micelle interactions displaying synergism at low nonionic surfactant mole fractions and slight antagonism at high nonionic mole fractions. The asymmetry in interaction produces an S-shaped CMC curve and demonstrates that the one-parameter Rubingh model is insufficient in describing both synergism and antagonism for this binary mixture. © 2013 AOCS.

Duke Scholars

Author Louis P Jackson Biomedical Engineering