LAUSR

Charged fluids are ubiquitous in biology and in everyday products such as milk, cosmetics, lubricants, paints, or drugs. The stability and aggregation of charged colloidal solutions are of outstanding relevance in nature and in diverse biomedical applications, including the fabrication of photonic materials and scaffolds for biological assemblies, gene therapy, diagnostics, targeted drug delivery, and molecular labeling. When an electrode or a charged colloidal particle is immersed in a Coulombic fluid, an ionic cloud or electrical double layer forms. One of the most simple theoretical descriptions of the electrical double layer can be provided via the non-linear Poisson-Boltzmann theory of point-ions. In planar geometry, it is possible to derive an analytical description of the electrical double layer for z : z electrolytes. In spite of its simplicity, this mean field approach neglects important characteristics of charged fluids such as ion correlations, ionic excluded volume, polarization effects, etc. Thus, in this review article I would like to discuss some consequences of breaking the symmetry in the ionic size and/or valence of charged fluids in the presence of an external field when ion correlations and ionic excluded volume effects are included consistently. The external field can be produced by a charged electrode or an electrified colloidal particle, and the associated electrical double layer is studied via integral equations theory, and/or molecular simulations beyond the classical non-linear Poisson Boltzmann theory of point ions.