"This is an unexpected phenomenon, contrary to what we thought we knew about nanopore transport. It took three years to work out what it was the simulations were showing us. After exploring many potential solutions, the breakthrough came when we realized that we should not assume water is incompressible. Now that we understand what's happening in the computer simulations, we are able to reproduce this phenomenon in theoretical calculations."<p>Pretty interesting that the rules of the simulation were such that it took three years to explain an emergent phenomenon. I probably would have written it off as floating point shenanigans.
It's always surprised me how many people do not know that water is incompressible! For example, when someone is filling a scuba tank, it's common to put the tank in a large, often metal-sided container of water. When asked why, the shop staff member will typically say: "In the unlikely event of the tank blowing up, the water will absorb the force of the explosion." But in fact, water being incompressible, it will absorb approximately 0% of that force - which is then transmitted undiminished to the metal walls - which then explode like a giant hand grenade, promptly maiming or killing everyone standing nearby! The purpose of the water is instead, to absorb the heat from adiabatic compression, and keep the tank cool.
That is a really neat effect. Basically if you can put a water molecule inside a flat field it lines itself up with that field and can be compressed. I would bet this has an impact on Graphene based desalination efforts as well.
> <i>Aksimentiev adds, "All of this only works because the membrane is so thin, and the electric field is focused where the membrane is, compressing the water molecule from both sides.</i><p>It's not _pushing_ the molecules together, rather _pulling_ them together. This happens because the electric field is smaller than the water molecule, and pulls from inside.
<i>”Wilson found that a high electric field applied to a tiny hole in a graphene membrane would compress the water molecules travelling through the pore by 3 percent”</i><p>So, it changes the distances between the atoms of a water molecule? If so, would that mean this can affect chemical reactions involving dipoles, too?
Who said water does not compress? It doesnt compress much, but at the depths of the ocean it is a tiny bit denser than at the surface. I was suprised to see phys.org so cassually state that it doesnt.
> "Physics Professor Aleksei Aksimentiev and his post doctoral researcher James Wilson found that a high electric field applied to a tiny hole in a graphene membrane would compress the water molecules travelling through the pore by 3 percent."<p>Ahh, "3 percent" means that from a fluid dynamics point of view, the incompressibility assumption is still a good assumption valid for most macroscopic applications. :) Still very impressive to achieve that under ambient pressure with an electric field gradient.
What would happen if you compress water using this method and then seal the container it's in and turn off the electricity? Anything interesting? Does the water stay compressed? Does the container explode? Does it depend on the strength of the container?