Overcharging by macroions: above all, an entropy effect

Abstract

Model macroion solutions next to a charged wall show interface \textit{true overcharging}, charge reversal and inversion, and layering. Macroion layering is present, even if the wall or the macroparticle are \textit{uncharged} or if the wall and macroions are like-charged. An effective long-range attractive force between the adsorbed macroions is implied. The results are obtained through an integral equation theory and a new extended Poisson-Boltzmann theory, and are in accordance with experiments on confined macroions and polymer layering.