Embarras de richesses in non-DLVO colloid interactions

TL;DR

This paper reviews the complex and diverse nature of colloid interactions beyond classical DLVO theory, highlighting recent experimental advances that reveal richer underlying mechanisms.

Contribution

It provides a comprehensive overview of modern developments and experimental findings that challenge and extend the traditional DLVO framework for colloidal interactions.

Findings

Revealed the limitations of classical DLVO theory

Highlighted the importance of non-mean-field electrostatics and ion correlations

Summarized recent experimental progress in understanding colloid interactions

Abstract

In its original formulation, the seminal Deryaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability seemed like a simple but realistic description of the world of colloid interactions in electrolyte solutions. It is based on a straightforward superposition of the mean-field Poisson-Boltzmann (PB) electrostatics with the electrodynamic van der Waals (vdW) interactions driven by thermal and quantum fluctuations. However, subsequent developments continued to reveal a much richer and deeper structure of fundamental interactions on the nano- and micro-scale: the granularity and structure of the solvent, charging equilibria of dissociable charge groups, inhomogeneous charge distributions, the finite size of the ions, non-mean-field electrostatics, ion-ion correlations, and more. Today, the original simplicity is gone and we are left with an embarrassingly rich variety of interactions that defy simple classification and reduction to a few fundamental mechanisms. In this mini-review, we comment on the contemporary state-of-the-art picture of colloidal interactions, in view of some recent progress in experiments.