The mechanism of clouding in triton X-100: The effect of additives

Abstract

The mechanism of clouding in the nonionic surfactant is investigated through the effect of additives. The cloud point of Triton X-100 is shown to be very sensitive to the additions of small amounts (10 −5 M) of charged surface active agents while the cloud point remains unaltered on addition of same amount of the salt NaCl and n-butanol (10 −5 M). This is considered to be a clear indication of the result of charging the micellar surface. The linear rise in the clouding temperature of a Triton X-100 with the addition of additives sodium lauryl sulfate, sodium decyl sulfate, and sodium dodecyl benzene sulfonate up to a maximum concentration of 1 molecule per micelle of Triton X-100, is interpreted in terms of the rise in surface charge of the micelle. It is concluded that these observations support the view of regarding the cloud point as a critical phenomenon rather than the growth of micelles.