A theoretical exploration of the influencing factors for surface potential

Although it has been widely used to probe the interracial property, dynamics, and reactivity, the surface potential remains intractable for directly being measured, especially for charged particles in aqueous solutions. This paper presents that the surface potential is strongly dependent on the Hofmeister effect, and the theory including ion polarization and ionic correlation shows significant improvement compared with the classical theory. Ion polarization causes a strong Hofmeister effect and further dramatic decrease to surface potential, especially at low concentration; in contrast, ionic correlation that is closely associated with potential decay distance overestimates surface potential and plays an increasing role at higher ionic concentrations. Contributions of ion polarization and ionic correlation are respectively assessed, and a critical point is detected where their contributions can be exactly counteracted. Ionic correlation can be almost neglected at low ionic concentrations, while ion polarization, albeit less important at high concentrations, should be considered across the entire concentration range. The results thus obtained are applicable to other interfacial processes.