Effect of Formamide on the Surface and Thermodynamic Properties of some Surfactant Solutions

From the measured surface tension data, surface properties and thermodynamic quantities of micellization, adsorption at the air-liquid interface and transfer from water to mixed solvent (formamide + water) have been determined for the systems : (1) Sodium Dodecyl Sulphate + Formamide + Water; (2) Dodecyl Trimethyl Ammonium Bromide + Formamide + Water and (3) Triton X-100 + Formamide + Water. The process of micellization in the bulk solution and the adsorption of surfactants at the air-liquid interface are favoured by the enthalpy as well as the entropy effects. The results have been descirbed in terms of the intermolecular interaction of the components in the solutions.