Strange violation of the rules: Such charges can attract each other
There is a surprising explanation for the mysterious violation of electromagnetic rules. Water helps attract charges to each other. This effect has far-reaching implications for chemistry and biology.
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Particles that should repel each other are suddenly attracted to each other – for a long time this was impossible to explain theoretically. But now it turns out that you just have to take a closer look.
Opposite charges attract each other, just as charges repel each other, but this is not always true. Under certain conditions, charged particles can break these rules, a working group led by Madhavi Krishnan of the University of Oxford has found. However, you need some help, As the team now reports in the specialized journal Nature Nanotechnology.. Particles dissolved in a liquid can interact with its molecules in such a way that like charges attract each other. Such effects can break the symmetry between charges: positively charged particles attract each other, while at the same time negatively charged particles repel each other. This discovery has far-reaching implications for phenomena such as crystal formation or interactions between proteins.
It has been known for a long time, especially in biology, that molecules with the same charge or even larger structures sometimes seem to attract each other. But what was missing was clarification: all other interactions were considered too weak to compensate for the cacophony of accusations. To solve the puzzle, the working group examined the behavior of negatively and positively charged silicate nanoparticles in water and ethanol. The explanation for the strange attraction of similarly charged particles lies in the behavior of water on the surface of the particles. Their charges impose a certain order around the charged particles on water molecules, which also have negative and positive regions.
As the team notes, the spatial arrangement of particles can become increasingly less energetic when two negatively charged particles move toward each other. Up to a certain distance, the energy released is greater than the energy that must be used to overcome the repulsion of the charges themselves. This means that evenly charged particles are attracted to each other over greater distances. This causes the negatively charged nanoparticles in water to form ordered clusters through their attraction. On the other hand, positively charged particles do not experience such an energy gain in water, but rather continue to repel each other.
However, that changes to alcohol. Its molecules arrange themselves on surfaces in such a way that their positively and negatively charged areas align with those in water. Accordingly, the effect of rearranging them also has the opposite sign: positive charges attract each other, while negative charges do not. In addition, the working group demonstrates how to measure and predict critical forces and potentials on surfaces. The impact has far-reaching consequences for a whole range of disciplines and applications. This could potentially affect the behavior of many biological structures, change the solubility of nanoparticles or chemicals, or cause things to clump together that shouldn't ideally clump together.
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