The interfacial bending moment and curvature elastic moduli are related theoretically to the surface potential, Delta V, which is liable to direct measurement, The dependence of the interfacial bending properties on the position of the Gibbs dividing surface is investigated, As an application, experimental data for the surface potential of micellar surfactant solutions containing Al3+ ions are analyzed, The changes in the bending moment, as determined from Delta V potential, correlate with the transition from spherical to cylindrical micelles induced by the Al3+ ions, The results can be important for interpretation of data for formation of microemulsions, flocculation in emulsions, fluctuation capillary waves at interfaces and biomembranes, interactions between inclusions in lipid bilayers, etc.