Physicists have identified a new state of matter, hidden in the mysterious transformations that take place between the liquid and solid states of glass.
The transition of glass has a great fascination for scientists, and the new state of matter – called “liquid glass” – has a behavior at the microscopic level that has not been seen so far, marking it as separate from previously observed phenomena.
This new state appears to exist between a solid and a colloid (such as a gel): homogeneous mixtures with microscopic particles, but still larger than atoms and molecules, and easier to study. In this case, small plastic ellipsoidal colloids were created and mixed, as appropriate, in a solvent.
“This is incredibly interesting from a theoretical point of view,” says Matthias Fuchs, a professor of condensed soft matter theory at the University of Konstanz in Germany.
“Our experiments provide the kind of evidence for the interaction between critical fluctuations and the glassy arrest that the scientific community has been pursuing for some time.”
When materials turn from liquids to solids, their molecules usually align to form a crystalline pattern. Not the same with glass, which is why scientists are so eager to analyze and deconstruct it: with glass (and glass-like materials), molecules are blocked or frozen in a disordered state.
In liquid glass, scientists have observed that colloids could move but not rotate – they had more flexibility than glass molecules, but not enough to make them comparable to ordinary materials that have already been studied extensively.
Using ellipsoidal colloids rather than standard spherical shapes, these blocked rotations could be observed. The particles were grouped together in groups with similar orientations, which then obstructed each other inside the material.
Ellipsoidal particles in liquid glass clusters. (Research groups by Professor Andreas Zumbusch and Professor Matthias Fuchs)
“Due to their distinct shapes, our particles have orientation – unlike spherical particles – which gives rise to completely new and previously studied types of complex behaviors,” explains Andreas Zumbusch, professor of physical chemistry at the University of Konstanz.
Researchers say that the new state of matter is actually two competing liquid-solid transitions that interact, creating the mixture of different properties. The shape and concentration of the particles seem to be crucial in creating this liquid bottle.
As always with glass transitions, a lot of unanswered questions remain, but the study’s authors hope that the discovery of liquid glass – which scientists have predicted for twenty years – can help us understand how glass transitions work best. small scales.
The discoveries have the potential to go far beyond glass, shedding light on everything from the smallest biological cell to the largest cosmological system – any scenario in which there is an inexplicable disorder.
“Our results provide insight into the interaction between local structures and phase transformations,” the researchers write in their paper.
“This helps guide applications such as self-assembly of colloidal superstructures and also provides evidence of the importance of shape in the transition of glass in general.”
The research was published in PNAS.