Electrostatics interactions provide tunability for the properties of soft materials. The electrostatic interactions are sensitive to various tuning parameters including solvent permittivity, electrolyte valence, size and concentration, and interfaces. Despite long-term usage of electrostatics in controlling the soft matter properties, such as buffer system in biology, the understanding of electrostatics interactions is still limited. Here we discuss about our researches on the effects of surface polarization on the electrostatic interactions between ion-containing emulsions, and the effects of electrolyte concentration on the electrostatic interactions between colloids. The researches shed light on why classical electrostatic theories such as the DebyeâHückel theory and even the non-linear Poisson Boltzmann theory break down in recent electrostatic mediated experiments.
