The Giant SALR Cluster Fluid: A Review

Abstract

We review recent developments in understanding the behaviour of equilibrium fluids with competing short-range attractions and long-range repulsions at low concentration. Typically, this SALR model system is used to represent solutions where at least one of the solute species interacts via a screened-coulomb potential, which includes many colloidal, nanoparticle and polyelectrolyte solutions among others. Provided neither the short-range or long-range interactions are too strong, and the concentration remains sufficiently low, then discrete spherical clusters of solute are expected, here called "Giant SALR clusters". Because these clusters can themselves be disordered, as though fluid particles with a renormalised interaction, such cluster fluids cannot be treated using standard mean field methods. Our review therefore focuses on theoretical routes that aim to overcome this difficulty. We highlight the main outcomes of these theories and discuss how they relate to soft matter and especially biology, including complex coacervates, membraneless organelles and the origin of life.

Debye vs. Casimir: controlling the structure of charged nanoparticles deposited on a substrate

“…2a,c). Such potentials, called SALR (short-range attraction, long-range repulsion) or mermaid potentials [46], have attracted much attention recently, as they can give rise to a variety of complex structures and mesophases [46][47][48][49][50]. We will see that the emergence of such repulsive tails in our potentials can influence the nanoparticle behaviour in a nontrivial way.…”

Competition between clustering and phase separation in binary mixtures containing SALR particles

“…Four recent reviews witness the large interest in the study of SALR fluids and progress in this field. 20,28,37,41 The aforementioned scenario becomes even richer when considering (binary) mixtures: despite the huge number of works investigating self-assembly in one-component SALR fluids, much less effort has been devoted to analyse their mixtures with other species. In this context, it is worth mentioning a mixture of dimers and spheres interacting through a combination of attractive and repulsive potentials.…”

Investigation of molecular and mesoscale clusters in undersaturated glycine aqueous solutions

“…However, structure and composition of mesoscale clusters and phase behaviour of such mesostructured liquid phases is very little understood. There has been recently emerging theoretical understanding of thermodynamics of such phases and potential mechanisms of their formation through competing short-range and long-range interactions [47][48][49][50], but there is a lack of experimental data on phase behaviour and properties of mesostructured liquid phases.…”