(Table 2). The values of the critical aggregation concentration (CAC)of ethanol obtained from the isotherms of the surface tension, den-sity and dynamic viscosity of the aqueous solutions of the TX-100and CTAB mixture with ethanol are close to those determined byKahlweit et al. [17] at 25◦C, but lower than those obtained by Zanaand Eljebari [16], and Hayashi and Udagawa [18] from the proper-ties of the aqueous solutions of “pure” ethanol. Some differencesbetween the values of CAC obtained by us and those of Zana andEljebari [16] result probably from the fact that CAC is not one pin-point value but it is a range of the concentration in which the aggre-gates are formed and each method can give a different CAC value.The data obtained by Zana and Eljebari [16] were based on the flu-orescence measurements and the CAC was obtained at the temper-ature (298 K) different from that used in our experiments (293 K).