Computational study of soft Nanoparticles and effect of ions

Nanoparticles are object of intense scientific investigation because of their potential application in a variety of fields as medicine, cosmetics, toxicology, food and environment science. The understanding of the properties and processes occurring in solutions of charged nanoparticles, requires the determination of the structure of the interface region between their charged surface and the neutralising diffuse layer of counter-ions. The first part is dedicated to understand the effect of the surface charge density on the charge reversal phenomenon. We focus on the valence and ion concentration range at which reversal in the electrophoretic mobility is expected to happen. Although the mechanism responsible for the colloidal charge reversal is still a controversial issue, it is proved that ionic correlations are behind the appearance of such phenomenon (especially near the colloid surface). Other key factor that determines the charge reversal is the surface charge density of the nanoparticle. Our Results will appear therefore as an explanation of the limitations of the theoretical and analytical predictions.