The possibility to form the mixed micelles of TX-100 and CTAB in water + ethanol media depends on the interactions between the molecules of TX-100 and CTAB. These interactions decide about the composition of the micelles and they can be determined bythe ˇ parameter. The molecular interaction parameter, ˇ, for the Fig. 7. A plot of the critical micelle concentration (CMC) of the TX-100 and CTAB mixture in the mixed water + ethanol solvent vs. TX-100 mole fraction in the mixture with CTAB (˛). Curves 1–3 correspond to the constant ethanol concentration equal to 0.07, 1.07 and 3.21 M, respectively. monolayer, can be evaluated, among other ways, by using the equation derived by Rubingh and Rosen [1,38,39]: