Study the effect of ethanol on the formation of the wormlike micelles for a mixture of ionic surfactants

In this research, the anionic sodium Dodecyl Sulfate SDS surfactant had been blended with the cationic cetyltrimethylammonium bromide CATB surfactant using different concentrations (0.002-0.04M ) of ethanol and at temperature ranges (293.15K, 298.15K, 303.15K and 308.15K). Through the viscosity measurements for a mixture of SDS / CTAB and at certain mixing ratios (10 / 90,20 / 80,30 / 70 and 40/60), it was found that the viscosity was increased in the presence of ethanol, leading to the growth of wormlike micelles. This increases could be attributed to the increases in the connections (Cross linking) caused by ethanol between the chains of the wormlike micelles, which in turn inevitably lead to an increase in viscosity as a result of cage effect. Also, the used alcohol didn't participate in the mechanism of wormlike micelle formation because there wasn't any clear effect on the ratio that gives greater viscosity. This confirmed the credibility of critical intermolecular forces theory (CIF). Moreover, thermodynamic functions as well as the activation energy for the process of micelles formation for the studied ratios were calculated.