Application of charge regulation model for evaluation of surface ionization parameters from atomic force microscopy (AFM) data

The present state of affairs with calculation of electrostatic interaction between two charge regulated surfaces is briefly reviewed, placing a special emphasis on assumptions and limitations of underlying physical models. An application of the charge regulation model for evaluation of surface ionization parameters from the interaction force profile measured with an atomic force microscope in a symmetric silica–silica system is demonstrated. The site density and the dissociation equilibrium constant of surface silanols are determined. As can be judged from the results obtained, surface silanols are considerably more acidic than it was considered before.