MICELLE FORMATION BY ANIONIC AND CATIONIC SURFACTANTS IN 18-CROWN-6 ETHER-CYCLODEXTRIN+WATER SYSTEMS(BETA)

The conductances of sodium decyl sulfate (SDeS), sodium dodecyl sulfat e (SDS), dodecyltrimethylammonium bromide (DTAB), and trimethyltetrade cylammonium bromide (TTAB) have been determined in 18-crown-6 ether+wa ter (CR+W), beta-cyclodextrin+W (CYC+W), and in CR+CYC+W mixtures with fixed 0.0151 mol dm(-3) of CR and varying the amount of CYC with the overall change in the mole-fraction range of CYC from 0.0 to 0.5 in a CR+CYC+W mixture at 30 degrees C. From the conductivity data, the crit ical micellar concentration (cmc), degree of counter ion dissociation (beta), free energy of transfer of the surfactant hydrocarbon chain fr om medium to the micelle (Delta G degrees(HP)), and free energy of tra nsfer of surface contributions (Delta G(s)degrees) of SDS, SDeS, DTAB, and TTAB have been computed. It has been found that the micelles of a nionic surfactants are stabilized in a CR+W mixture in comparison to t hat in pure water, whereas micelles of cationic surfactants remain mor e or less unaffected. Micelles of all of the above surfactants are den atured as the amount of CYC is increased in the CR+CYC+W mixture. The effect of denaturisation is stronger on the micelles of SDS and TTAB i n comparison to that of SDeS and DTAB, respectively.