A team of scientists from Germany and the Netherlands have used a technology called confocal microscopy to discover a new state of matter, Liquid Glass, hidden inside mysterious transformations that happen between liquid and solid states of glass.
“Suspensions of colloidal particles are widely spread in nature and technology and have been studied intensely over more than a century,” said co-senior author Professor Andreas Zumbusch, Department of Chemistry, University of Konstanz. “When the density of such suspensions is increased to high volume fractions, often their structural dynamics are arrested in a disordered, glassy state before they can form an ordered structure.”
He also explained that till date such experiments were being performed using spherical colloids. However, an increased interest in synthetic colloids as material building blocks led to “development of a multitude of novel techniques for the synthesis of colloidal particles with specific geometries and interactions.”
The scientists, in this research, focused on ellipsoidal polymethylmethacrylate colloids. “Due to their distinct shapes our particles have orientation, as opposed to spherical particles, which gives rise to entirely new and previously unstudied kinds of complex behaviors,” he explained.
Researchers recorded temporal development of the 3D positions and orientations for nearly 6,000 ellipsoidal particles using confocal laser scanning microscopy. “At certain particle densities orientational motion froze whereas translational motion persisted, resulting in glassy states where the particles clustered to form local structures with similar orientation,” Zumbusch said.
“What we’ve termed liquid glass is a result of these clusters mutually obstructing each other and mediating characteristic long-range spatial correlations,” he explained. “These prevent the formation of a liquid crystal which would be the globally ordered state of matter expected from thermodynamics.”
As a result, the team noticed a regular phase transformation and a nonequilibrium phase transformation interacting with one another.