Mixed Micelles of Triton X‐100 and Sodium Dodecyl Sulfate and Their Interaction with Polymers

Abstract

Micellization of polyoxyethylene tert‐octylphenyl ether, Triton X‐100 [TX‐100], and sodium dodecyl sulfate [SDS] and their mixtures at varying mole fraction was investigated by surface tension measurements at 30°C. Changes in the critical micelle concentration (CMC) with the composition of the two surfactants so determined were analyzed by applying the Rubingh's regular solution theory to obtain interaction parameter, β ( = −3.81) showing synergism. Sodium dodecyl sulfate shows a remarkable interaction with polyethylene oxide [PEO, mol. wt. = 6000] and polyethylene oxide–polypropylene oxide–polyethylene oxide block copolymer [P65: EO₁₉PO₃₀EO₁₉, total mol. wt. = 3400, % EO = 50], while no such interaction was observed for TX‐100. Interaction weakens in mixed micelle and diminishes when the mole fraction of TX‐100 in mixed system increases. Turbidimetric studies show that the presence of TX‐100 in SDS improves calcium ion tolerance.

Acknowledgment

Financial assistance from U.G.C. Project no. F.12‐36/98 (SR‐I) is gratefully acknowledged.