Interaction parameters binary surfactant systems

Since Rubingh [9] proposed the so-called P" parameter to evaluate interactions between surfactants in a mixed micelle, Rosen and co-workers have done extensive work on the interaction between surfactants in a binary-surfactant system and introduced a new parameter, p [10] (pii for liquid-liquid interface [11], pis for liquid-solid interface [12]) to measure the interaction between surfactants in mixed monolayer at the surface of an aqueous solution. 

Wilson and co-workers developed a statistical mechanical model for single component surfactant adsorption (29-31) and expanded it to a binary system (2,3). Different adsorption curves were generated by varying the Van der Waals interaction parameters. The mixed adsorption equations that were developed were very complex and were not applied to experimental data. 

The miceUization of binary surfactant solutions is studied by the method of tensiometry at the variation of the fraction of ionic surfactant within the range 0-1.0. The quantitative treatment of the surface tension isotherms within the framework of the phase separation modeP showed that the values of the interaction parameter p in these systems lay within the range (-0.85)-(-. 6). This indicates that in these systems synergetic behaviour occurs, i.e. the mixed aggregates are formed. The surface potential is calculated for all the systems. A decrease in the potential is shown to occur with a decrease in In... 

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