Silver Nanoparticles: ‘Stable Crystal Configuration’ On The Inside, Behave Like Liquid On The Outside

An interesting phenomenon has been discovered about silver nanoparticles. Silver nanoparticles, from the outside, appear to behave liquid droplets, according to a research team led by MIT professor Ju Li. Li and his team, made up of researchers from China, Japan, and the United States, say that they have discovered that, even still, from the inside, these wobbling particles retain a “perfectly stable crystal configuration,” according to Science Daily.

The results of the team’s research is published in Nature Materials. The team’s experiments were conducted on nanoparticles consisting of pure silver no larger than 10 nanometers across. For reference, these silver nanoparticles are less than one-thousandth of the width of a human hair.

Nanoparticles have an ever-growing list of uses, from pharmaceuticals to electronics. Li says that in nanotechnology, scientists generally “want to form shapes, and they want these shapes to be stable, in many cases over a period of years.” The fact that the nanoparticles, which are perfectly stable on the inside, behave like a liquid at room temperature was quite unexpected — and kind of disappointing for the uses researchers are hoping to apply nanotechnology to. Science Daily gave the example that if a gold or silver “nanoligament” is used in electronic circuits, the wobbly behavior might cause the connections in the circuits to fail.

“The interior is crystalline, so the only mobile atoms are the first one or two monolayers,” Li said of the silver nanoparticles. “Everywhere except the first two layers is crystalline.”

Still, Li says that the team’s discovery is a very important one, and now that researchers understand what they call a “defect,” researchers creating nanotechnology will be able to compensate for the wobbly exterior of the silver nanoparticles.

“Now that the phenomenon has been understood, researchers working on nanocircuits or other nanodevices can quite easily compensate for it, Li says. If the nanoparticles are protected by even a vanishingly thin layer of oxide, the liquidlike behavior is almost completely eliminated, making stable circuits possible,” Science Daily reported.

The findings also might be able to help researchers explain anomalies that have been seen in other research into nanoparticles and small particles of metal, according to Li.

Horacio Espinosa, a professor of manufacturing and entrepreneurship at Northwestern University, told Science Daily that Li’s research into the nature of silver nanoparticles is a major accomplishment in the field of nanotechnology.

“This has implications to many aspects of mechanics of materials, so I expect this work to be highly cited,” Espinosa said of the silver nanoparticle research paper.

[Photo Credit: Yan Liang via Science X Network]