Physicists have identified a new state of matter, hidden within the mysterious transformations that take place between the liquid and solid states of glass.
The transition of glass is very fascinating to scientists and the new state of matter, called “liquid glass”, has a behavior at the microscopic level that had not been seen before, marking it as separate from the phenomena observed above.
This new state appears to exist between a solid and a colloid (such as a gel): homogeneous mixtures with microscopic particles but even larger than atoms and molecules and easier to study. In this case, tiny custom-made ellipsoidal colloids were created and mixed into a solvent.
“This is incredibly interesting from a theoretical point of view,” says Matthias Fuchs, a professor of soft condensed matter theory at the University of Konstanz in Germany.
“Our experiments provide the kind of evidence for the interaction between critical fluctuations and glass arrest that the scientific community has been looking for for quite some time.”
When materials are transformed from liquids to solids, their molecules usually align to form a crystalline pattern. It doesn’t happen with glass, which is why scientists are so interested in analyzing and deconstructing it: with glass (and glass-like materials), molecules are blocked or frozen in a disordered state.
In liquid glass, scientists noticed that the colloids were able to move, but they could not rotate; they had more flexibility than glass molecules, but they were not enough to make them comparable to the usual materials that have already been studied extensively.
By using ellipsoidal colloids instead of the standard spherical shapes, these blocked rotations could be observed. The particles were grouped into groups with similar orientations, which then clogged each other within the material.
Ellipsoidal particles in clusters of liquid glass. (Research groups of Professor Andreas Zumbusch and Professor Matthias Fuchs)
“Because of their differentiated shapes, our particles have orientation, unlike spherical particles, which results in completely new and unstudied complex behaviors,” explains Andreas Zumbusch, a professor of physical chemistry at the University of Konstanz.
Researchers say the new state of matter is actually two transitions from liquid to solid in competition that interact, creating the mixture of different properties. The shape and concentration of the particles appear to be crucial in creating this liquid glass.
As is always the case with glass transitions, many questions remain unanswered, but the study authors hope that the discovery of liquid glass, which scientists have been predicting for twenty years, can help better understand how transitions work. of glass. scales.
Findings can also go far beyond glass, shedding light on everything from the smallest biological cell to the largest cosmological system, any scenario where there is an unexplained disorder.
“Our results give an idea of the interaction between local structures and phase transformations,” the researchers write in their article.
“This helps guide applications such as the self-assembly of colloidal superstructures and also demonstrates the importance of shape in the overall glass transition.”
The research has been published in PNAS.