New Study Shows Like-Charged Particles Attract or Repel in Solution

You know how like-charged objects repel — and do so regardless of the sign of their electrical charge? Maybe not always, according to new research published in Nature.

"We demonstrate experimentally that the solvent plays a hitherto unforeseen but crucial role in interparticle interactions," they write. But more importantly, "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 like alcohols "that exhibit an inversion of the net molecular dipole at an interface"], 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.

The delicate interplay of interactions between objects in the fluid phase influences the behaviour, organization and properties of systems from nanometric to more macroscopic size and length scales and thus underpins a wealth of natural phenomena...
Thanks to long-time Slashdot reader Greymane for sharing the article.

Anyone got a dumbed-down version?

[Eunomion]

I get what they're saying they found, but not the explanation of why it's happening.

Re:Anyone got a dumbed-down version?

[Calydor]

Magic aliens.

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[Powercntrl]

I'm sure it's confusing ICP too and they're writing a rap song about it as we speak.

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[GrumpySteen]

There's not a complete explanation. Just a lot of very interesting observations and some theories. This is the sort of "oh, that's weird" initial research that sometimes forms the basis of a lot of interesting new developments.

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[spaceman375]

They do a bunch of hand waving misdirection without really explaining what's going on. I suspect they'd rather not postulate yet.

Allow me to armchair amateur an explanation: At these scales, everything is in motion, mostly random but with some currents (river or stream-like, not electrical). In water, the aqueous solution part, there are relatively free electrons hanging around in the mildly ionic solvent. With alcohols, the molecules have a relatively positive localized spot, more concentrated than the d

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[Eunomion]

Emergent properties of more than one order usually breeze right over my head. If that's what they're talking about. Like the influence of large groupings in motion producing local effects.

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[hdyoung]

In a super-rough nutshell, when you put a chunk of material in a liquid with a bunch of + and - ions, weird multiple layers of charge accumulate around the material chunk and lead to strange interactions between particles. These interactions are important because situations like this (particles-in-ionic-liquids) arise in the ocean, in shampoo, in cooking, and in basically every part of your body. The main theory that describes these effects is DLVO theory, which is a combination of equations that describe

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[Eunomion]

Thanks. So this paper is mainly describing the observation rather than offering explanations?

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[RUs1729]

I get what they're saying they found, but not the explanation of why it's happening.

According to the religious crowd it would be because God did it.

Re:Anyone got a dumbed-down version?

[PPH]

Super simple explanation:

When you have a (-) particle in solution, it attracts a bunch of (+) particles. Which in turn attract some (-) particles at longer distances.

Also, polar solution molecules get their (+) ends attracted to the (-), dragging their own (-) ends along behind them. Weird stuff ensues.

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[Eunomion]

So, like road traffic dynamics.

Like holes in semiconductors

[nsaspook]

Their process looks like a type of doping. Net positive current flow from the vacancy of electrons or negative charge.
https://www.allaboutcircuits.c... [allaboutcircuits.com]

Is this good for Electric Universe theory?

[blue trane]

No?

Not suprising

[wakeboarder]

water is a polar molecule, so you also have to consider all the polar molecules between particles. This means it isn't just the electric field that comes into play, but how it is affected by other molecules in the solution.

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[ceoyoyo]

It's sensitive to pH, so it's not the polar molecules that are doing it. It's the good old H+ and OH- ions.

The summary is probably misleading

[ffkom]

The statement "negatively charged particles can attract at long range" sounds as if they found a source of free energy, which they most likely did not find. Sure, two planets can also attract at long range because of gravity, even if they are both slightly negatively charged. But gravity is probably not involved here. They observed clustering of particles in solution, and there are certainly a lot of not-yet-well-understood mechanisms to find in that, but the summary sounds over-generalized.

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[blue trane]

What if two planets attract at long range because of electricity, not gravity?