  The accurate characterization of electrical double layer properties of
nanoparticles is of fundamental importance for optimizing their physicochemical
properties for specific biotechnological and biomedical applications. In this
article, we use classical solvation density functional theory and a surface
complexation model to investigate the effects of pH and nanoparticle size on
the structural and electrostatic properties of an electrolyte solution
surrounding a spherical silica oxide nanoparticle. The formulation has been
particularly useful for identifying dominant interactions governing the ionic
driving force under a variety of pH levels and nanoparticle sizes. As a result
of the energetic interplay displayed between electrostatic potential, ion-ion
correlation and particle crowding effects on the nanoparticle surface
titration, rich, non-trivial ion density profiles and mean electrostatic
potential behavior have been found.
