It should be stressed that the CAC of ethanol practically does not depend on the concentration and composition of the TX-100 and CTAB mixture. It means that the interactions of ethanol molecules through water are probably stronger than those between ethanol and surfactant. On the other hand, at the concentration higher than CAC, the presence of the surfactant micelles was not detected by Zetasizer Nano.
The interactions of ethanol molecules with water and surfactants should be reflected in the apparent and partial molar volumes of ethanol and water.
The apparent molar volume was determined from the following equation [27]: