Abstract

A. A. Patil and T. J. Patil

Commercially available technical grade non-ionic surfactants usually contain impurities and have a broad distribution of molecular weight owing to degree of ethoxylation. It has shown that the surface tension method (Wilhelmy plate) is very sensitive if impurities are present in surfactant. Much lower CMC values are obtained for technical grade surfactants with the surface tension method than with the dye solubilization method. The CMC determined by dye solubilization technique are in fair agreement with the values obtained by other available methods. The change in critical micellar concentration of Tween-40 has been studied through the influence of additive Chloramine-T in aqueous medium by measuring the absorbance of the pure surfactant and with Chloramine-T in presence of water insoluble dye Orange-OT by using dye solubilization technique. The absorbance was found to be increased with increased concentration of pure surfactant Tween-40. The absorbance of the mixed systems with Chloramine-T also shows the same trend. The CMC of pure surfactant get decreased with increased concentration of additive Chloramine-T. The influence of additive Chloramine-T on the absorbance of Tween-40 is clear indication that the phenomenon of dye micellization is associated with the different micelles coalescing.

Dye Micellization; Dye Solubilization; Absorbance (A); Tween-40 (TW-40); Chloramine-T (CAT); Critical Micelle Concentration (CMC)

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