A charge-dependent long-ranged force drives tailored assembly of matter in solution

Journal article

Understanding forces governing the behaviour of particles in solution is fundamental across a wide range of subjects such as biology, material science and nanotechnology. Interparticle interactions play a crucial role in processes such as crystallization, self-assembly and biomolecular folding, where higher-ordered structures are formed from the precise interplay of fundamental building blocks. Traditionally, we learned from electromagnetism that like-charged objects repel, a principle long assumed to hold true in solutions, especially in dilute electrolyte systems. However, recent studies suggest that this perspective may be overly simplistic; specifically, the solvent—traditionally considered a continuum—has now been demonstrated to exert a dynamic and often counterintuitive role at the molecular level, even reversing the expected electrostatic repulsion between particles of like charge. This thesis explores the like-charge attraction phenomenon across a broad range of solvents, co-solvents, and particle surface chemistries. Through rigorous experimental measurements and computational simulations, we establish the generality of this anomalous attraction. We highlight the observation of a strong, asymmetrical and long-ranged attractive component between like-charged particles that cannot be explained by conventional DLVO theory. The concept of electrosolvation is proposed, where ‘electro-’, refers to the fundamentally electrical nature of this contribution to the free energy, driven by the sign of charge of the objects; and ‘-solvation’ indicates the solvent or solvation-mediated nature of the interaction. Our findings provide a novel perspective in understanding and controlling interparticle interactions in both natural processes and industrial applications

Authors: Wang, S; Walker-Gibbons, R; Watkins, B; Flynn, M; Krishnan, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature Nanotechnology
• Volume: 19
• Issue: 4
• Pages: 485-493
• Publication date: 2024-03-01
• DOI: 10.1038/s41565-024-01621-5
• EISSN: 1748-3395
• ISSN: 1748-3387
• Language: English
• Keywords: Colloid; Solvation; Chemistry; Molecule; Dipole; Nanotechnology; Aqueous solution; Electrostatics; Physical chemistry; Organic chemistry; Chemical physics; Nanoscopic scale; Coacervate; Solvent; Surface charge; Materials science