ABSTRACT
This chapter describes the general concepts and quantitative methods most commonly applied to define and probe the electrical and chemical properties of charged surfaces. Measuring and modeling the electric charge at the solid–liquid interface is a mandatory prerequisite for catching the basic interfacial and colloidal features pertaining to powders and fibers, and for describing multiphasic systems on a mechanistic level. In the complete absence of a particle core, the soft particle becomes a spherical polyelectrolyte. In the interfacial region, the distribution of fixed charged groups in the ion-permeable layer takes place within distances comparable to, if not larger than, the Debye length, thus considerably modifying the electric potential distribution as derived from hard-surface models. The chemical models were developed for the evaluation of the thermodynamic constants associated with the surface ion exchange equilibria as in protonation and complexation reactions.
