Gibbs absorption isotherm

Surface films also form on solutions of soluble surfactant. In that case, the surface tension isotherm is measured as a function of concentration of surfactant in the solution. The surface pressure isotherm can be basically understood by the Gibbs absorption isotherm, which in the particular case of air-water interface relates the change of the surface tension to the chemical potential of the surfactant as ... 

The reason for the suppression of coalescence was sought in the repulsive electrical forces, which resulted from the electric potential difference at the G/L interface and resulted from the difference in ion concentrations there. Here Gibbs s absorption isotherm applies, which related the surface excess or deficiency to the differential quotient dcr/do ... 

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