Amazing stuff! Pardon, this is not the very latest research! However, this research maybe on to something fundamental?
"... It turns out that under certain conditions, like charges can actually attract each other instead. ... researchers ... demonstrated the attraction of like-charged particles in solutions.
The journey began ... back in the mid-2000s, when she came across the “like-charge attraction problem” while studying how DNA molecules squeezed into slit-like boxes. It was expected that the DNA would flatten into a pancake-like geometry, but instead it aligned alongside the edge of the box. Without any external forces being applied, the only explanation was that the DNA was attracted to the box, despite them both being negatively charged. ...
The like-charge problem is not new knowledge though. Different scientists over the years have tried to explain how like charges can attract, with some of the earliest works coming from Irving Langmuir back in the 1930s.
One of the areas where like-charge attraction is seen the most is within fluids, and the interaction of solid matter with fluids. ..."
"A study published today in Nature Nanotechnology shows that similarly charged particles can sometimes attract, rather than repel.
The team found that like-charged particles suspended in liquids can attract one another at long-range, depending on the solvent and the sign of the charge.
The study has immediate implications for processes that involve interactions in solution across various lengthscales, including self-assembly, crystallisation, and phase separation. ...
has demonstrated that similarly charged particles in solution can, in fact, attract each other over long distances. Just as surprisingly, the team found that the effect is different for positively and negatively charged particles, depending on the solvent. ...
has demonstrated that similarly charged particles in solution can, in fact, attract each other over long distances. Just as surprisingly, the team found that the effect is different for positively and negatively charged particles, depending on the solvent. ...
Using a theory of interparticle interactions that considers the structure of the solvent at the interface, the team established that for negatively charged particles in water there is an attractive force that outweighs electrostatic repulsion at large separations, leading to cluster formation. For positively charged particles in water this solvent-driven interaction is always repulsive, and no clusters form.
This effect was found to be pH dependent: the team were able to control the formation (or not) of clusters for negatively charged particles by varying the pH. No matter the pH, the positively charged particles did not form clusters. ..."
From the abstract:
"The interaction between charged objects in solution is generally expected to recapitulate two central principles of electromagnetics: (1) like-charged objects repel, and (2) they do so regardless of the sign of their electrical charge. Here we demonstrate experimentally that the solvent plays a hitherto unforeseen but crucial role in interparticle interactions, and importantly, that interactions in the fluid phase can break charge-reversal symmetry. We show that in aqueous solution, negatively charged particles can attract at long range while positively charged particles repel. In solvents that exhibit an inversion of the net molecular dipole at an interface, such as alcohols, we find that the converse can be true: positively charged particles may attract whereas negatives repel. The observations hold across a wide variety of surface chemistries: from inorganic silica and polymeric particles to polyelectrolyte- and polypeptide-coated surfaces in aqueous solution. A theory of interparticle interactions that invokes solvent structuring at an interface captures the observations. Our study establishes a nanoscopic interfacial mechanism by which solvent molecules may give rise to a strong and long-ranged force in solution, with immediate ramifications for a range of particulate and molecular processes across length scales such as self-assembly, gelation and crystallization, biomolecular condensation, coacervation, and phase segregation."
It’s not only opposites that attract – new study shows like-charged particles can come together (original news release)
Fig. 1: Interparticle interactions in solution can break charge-reversal symmetry.
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