Abstract
The surface tension of the aqueous solution of octyl methyl sulfoxide (OMS) was measured as a function of temperature at various molalities below and above the critical micelle concentration. The entropy and enthalpy of adsorption from monomeric and micellar states of surfactant were evaluated by applying the thermodynamic equations to the surface tension measured. The entropy and enthalpy of micelle formation were also evaluated. These thermodynamic quantities were discussed in terms of the orientation of surfactant molecules in the interface and in micelle, the hydration of hydrophilic group of surfactant, and the difference in geometry between the adsorbed film and micelle.
