Thermodynamic studies on water-beta-cyclodextrin-surfactant ternary systems

Conductance measurements are reported for double chain surfactants like N,N,N-octylpentyldimethylammonium (OPAC) and N,N,N-octyloctyldimethylammonium chlorides (OOAC) in water-beta-cyclodextrin solution. From the specific conductivity data, the apparent critical micelle concentration (cmc*) and the degree of counterion dissociation (beta) were obtained at a fixed beta-CD concentration (m(beta CD) = 0.01190 mol kg(-1)), besides from the cmc* value and that in water (cmc) the stoichiometry of the surfactant-beta-CD complex was calculated. Densities, heat capacities, enthalpies of dilution at 298 K and osmotic coefficients at 310 K were measured for the same systems; the apparent molar volumes, V-phi, and heat capacities, C-phi, of two surfactants in beta-CD solution, calculated as functions of surfactant concentrations m(s), have made possible to obtain the properties of transfer of the surfactant from water to beta-CD-water solutions.