Chemical control of self-assembly by the electrosolvation force

TL;DR

This paper introduces the electrosolvation force as a new interaction influencing self-assembly in solutions, demonstrating how interfacial electrolyte structure can be chemically tuned to control molecular organization.

Contribution

It reveals the physical chemistry behind the electrosolvation force and shows how neutral molecules can modulate self-assembly by altering interfacial solvent structure.

Findings

Electrosolvation force arises from interfacial electrolyte structure.

Neutral molecules can disrupt or reinforce solvent structure at interfaces.

This mechanism explains effects of co-solvents and osmolytes on proteins.

Abstract

Self-assembly of matter in solution generally relies on attractive interactions that overcome entropy and drive the formation of higher-order molecular and particulate structures. Such interactions play key roles in a variety of contexts, e.g., crystallisation, biomolecular folding and condensation, pathological protein aggregation, pharmaceuticals and fine chemicals. The electrosolvation force entails a new conceptual paradigm in the known palette of interactions that drive the spontaneous accretion and organisation of matter. However, an understanding of the underlying physical chemistry, and therefore the ability to exert control over and tune the interaction, remains incomplete. Here we demonstrate that this force arises from the structure of the interfacial electrolyte. Neutral molecules such as a different solvent, osmolytes or surfactants, can - even at very low concentrations in the medium - disrupt or reinforce pre-existing interfacial solvent structure, thereby furnishing unanticipated chemical tuning of the ability of matter to self-assemble. The observations further present unexpected mechanistic elements that may explain the impact of co-solvents and osmolytes on protein structure, stability and pathological protein condensation. Our findings shed new light on microscopic mechanisms that drive the emergence of order and structure from molecular to macroscopic scales in the solution phase.