A recent study published in Nature Nanotechnology has revealed that similarly charged particles in solution can exhibit long-range attraction. Surprisingly, the researchers found that the impact of this attraction varies depending on the type of solvent used.
The study, conducted by a team from the Department of Chemistry, challenged established theories by demonstrating that at large separations, negatively charged particles are attracted to each other while positively charged particles repel each other. This phenomenon was observed to be reversed in solvents like alcohol.
Through bright-field microscopy, the researchers observed negatively charged silica microparticles in water forming hexagonally arranged clusters, while positively charged aminated silica particles did not cluster. However, when the solvent was changed to alcohol, the opposite effect was observed.
The results of this study have significant implications for various processes involving molecular interactions and particle behavior at different length scales, such as phase separation, self-assembly, and crystallization. The researchers believe that these findings could lead to a fundamental recalibration in understanding processes related to molecular aggregation in human disease and the stability of pharmaceutical and fine chemical products.
The study also shed light on the properties of solvent-induced interfacial electrical potential, which were previously thought to be immeasurable. The researchers expressed pride in the collaborative effort of their graduate and undergraduate students in advancing this groundbreaking discovery.
Lead author of the study, Madhavi Krishnan, and first author, Sida Wang, both from the Department of Chemistry at the University of Oxford, emphasized the significance of these findings in expanding our understanding of particle interactions in solution.
The study, titled “A charge-dependent long-ranged force drives tailored assembly of matter in solution,” was published in Nature Nanotechnology. Source: University of Oxford.
