The Spectra of Iodine in an Aqueous Solution of Nonionic and Anionic Surfactants

Abstract

The interaction between pentaethylene glycol-dodecyl ether(C₁₂E₅) and sodium dodecyl sulfate (SDS) was investigated from the spectra of iodine in aqueous solution containing C₁₂E₅ and SDS. When SDS is added in the aqueous solution of C₁₂E₅ and iodine, the wave length of maxi-mum absorption shifted, and the absorbancy is reduced regularly, with the change of the con- centration of SDS added.
Two break points are observed in the plot of absorbancy against the concentration of SDS added, the first break point being at the 1/10 molar ratio of SDS to C₁₂E₅, and the second break point at the equi-molar concentration. The break points and the slope of the plot indicate that the interaction between C₁₂E₅ and SDS increases rapidly from the concentration. of 1/10 molar ratio of SDS to C₁₂E₅, and that the interaction reaches a miximum at the equimolar concentration.
These trends are observed for various concentration of C₁₂E₅.