Nanoparticles Change Crystal Structure When Wet

Roland Piquepaille writes "This news release from the University of California at Berkeley is quite astonishing. 'A UC Berkeley team comprised of physicists, chemists and mineralogists reports on the unusual behavior of a semiconducting material, zinc sulphide (ZnS), when reduced to pieces only 3 nanometers across. They found that when the surface of a ZnS nanoparticle gets wet, its entire crystal structure rearranges to become more ordered, closer to the structure of a bulk piece of solid ZnS.' My summary includes two images of a 3 nanometer zinc sulphide (ZnS) nanoparticle with or without surface-bound water. How can this be used for? Surprisingly, they think that it 'could provide a way to tell whether pieces of rock from outer space came from planets with water.'"

protein folding

[Anonymous Coward]

Looks like it could be the same kind of process that triggers folding in organic chains in the presence of water ? After all, the water matrix does exert certain forces on particles that are at the same scale, it probably triggers an avalanche effect on the ZnS crystal starting at the surface of the material.

Re:protein folding

[Anonymous Coward]

They should have probably included a molecular biologist in their team. Such structural changes happen all the time with large organic molecules in water media.

what about other compounds?

[chia_monkey]

I wonder what other compounds show the same response. It would be interesting to see if there were a variety, some semi-conductive, some non-conductive, etc. Then could we possibly join them and have only half of the larger compound (yet still a nanostructure) change when put in contact with water? It could act similar to a bimetal strip. I dunno...my brain is thinking of a bazillion different ideas and applications right now. I hope there are some geniuses on here that can answer this and throw out a few more ideas of what could be done.

Re:what about other compounds?

[tiled_rainbows]

What about a car that automagically transforms into a speedboat when it comes into contact with water?

Er, just don't drive it in the rain, I guess.

Re:Yawn

[muirhead]

Where's my coffee [slashdot.org]

You've got Karma to burn, but even so you could try a little harder.

From the article:

"Nanoparticles are probably widespread in the cosmos, and their surface environments may vary significantly, such as water versus no water, or the presence of organic molecules," said Jillian Banfield,

Another decade of research, and there might be a story here.

Why *only* water?

[DrSkwid]

Surely with the multitude of molecules there would be some other that would cause such a re-arrangement.

To conclude that a space rock was formed in the presence of water could be an expensive mis-interpretation, such as if a space exploration program was based on that assumption.

I'm not trying to debunk their research but without experimenting with a wide variety molecules in different pressures and temperatures all that can be concluded is that "these crystals order themselves in water" not "any ordered crystal formed in water".

I look forward to finding out why I am wrong.

Re:Why *only* water?

[Vacuum Sux]

Surely with the multitude of molecules there would be some other that would cause such a re-arrangement.

It is known that adsorption of molecules and atoms, not only water, on surfaces can change the surface tension of a material. The changes can lead to re-arrangement of the top most atomic layers giving different different crystal structures than in the bulk material.

If only . . .

[Brahmastra]

. . . the rearrangement went a bit further, becoming a replicator. I could use a replicator in my cube right now.

semiconductors and ai?

[PoPRawkZ]

could a semiconductor that could rearrange it's structure so that it could offer new circuits to become accessible? perhaps give a processor the ability to adapt to more efficiently use it's most common pathways?

Obviously

[WTFmonkey]

I obviously need to brush up on my physics. I read that description, closed my eyes, and couldn't remember a single word. There were probably some articles and prepositions, nouns and verbs, but I coudn't guarantee it. Might as well have said, "For cwedgy floomptorps now, wristwatches bedoggle one's crystal-o-morphix shindiggity. With extra bananas."

Why am I posting this, you ask? This article just looked like it needed a few more comments. Bye.

Metal - ligand interactions

[fven]

The interaction of metal nanocrystals is a burgeoning field of science.

The presence of ligands (things like water, carbon monoxide, dinitrogen) can and does change the structure of metal clusters.

In these interactions both the geometric structure (the physical shape of the thing - what we see being altered here) and the electronic structure are important.

If for example the sum of the bond strength between a metal atom and say the hydrogen of water, and another metal atom with the ohter hydrogen of water is stronger than the bond between the two metal atoms, then the water molecule can push the two metal atoms apart and form a bridge between them.
The degree of change can be measured by spectrosopies such as UV/vis, IR, Raman etc. that allow characterisation of types & strength of bonds and forces.

Finding examples of this behaviour and learning how it can be directed by say changing the geometry of the metal cluster and by changing the ligand or the metal composition has applications in materials science, fabrication (using "dumb" molecules to direct the formation of certain crystal structures may be cheaper than forcing high pressures and so on).

Very exciting science!

Re:Metal - ligand interactions

[meridoc]

Yes, if the bonds worked that way, that could happen.

But, metal-metal bonds (since they're actual bonds) will probably be stronger than any metal-water interactions. Water is not a good ligand. Sulfur, on the other hand, is an extremely good ligand, so since they're working with ZnS, I doubt it's anything to do with ligand interactions.