Liquid-liquid transitions crystallize new ideas for molecular liquids

November 25, 2019

Tokyo - Crystallization describes the formation of ordered structures from the disordered constituents of a liquid. Although the fundamental theory of crystal formation has been widely investigated and is generally well established, gaps in the understanding still remain. Researchers from The University of Tokyo, Institute of Industrial Science, and Tokyo Metropolitan University have reported experimental findings that reveal coupling between phase transitions that leads to drastic enhancement of crystal formation. Their findings are published in PNAS.

Within a liquid--even liquids made up of only one component--there can be multiple distinct phases with different properties. Variations in the experimental conditions can make the liquid change from one of these phases to another in a process called liquid-liquid transition (LLT). If these transitions occur just below the melting point of the crystal, they can affect its initial formation, known as nucleation. However, the mechanism for such effects and the general applicability of these observations remain unknown.

The researchers report a significant coupling of crystallization and LLT for the molecular liquid triphenyl phosphite. By annealing--cooling and keeping--the liquid at temperatures related to the LLT of the material, they were able to considerably enhance the nucleation rate and frequency of the subsequent crystallization.

"We were able to separate the kinetic and thermodynamic factors that contribute to crystal formation," study lead author Rei Kurita explains. "The LLTs caused by annealing lead to changes in the local order of the molecules. Because of the link we identified between crystallization and LLTs, these changes cause similar ones in the crystal phase, which lowers the energy between the crystal and liquid phases making it easier for crystals to nucleate. We hope that our findings can be used as a handle to direct crystallization behavior."

As well as leading to control and tailoring of crystallization effects, the researchers believe that their findings could also be used to probe material properties by identifying LLTs in materials where their effects are obscured by crystallization. For example, the approach could be used to gain a deeper understanding of water, silicon, germanium, and metallic liquid systems.

"Our findings provide useful insight for understanding and controlling crystallization," study author Hajime Tanaka explains. "We believe our work could have significant implications for both fundamental studies and industrial applications; for example, in achieving protein crystals for use in disease research, or in nanocrystalline materials for use in technology."
The article, "Drastic enhancement of crystal nucleation in a molecular liquid by its liquid-liquid transition" was published in PNAS at DOI:

About Institute of Industrial Science (IIS), the University of Tokyo

Institute of Industrial Science (IIS), the University of Tokyo is one of the largest university-attached research institutes in Japan.

More than 120 research laboratories, each headed by a faculty member, comprise IIS, with more than 1,000 members including approximately 300 staff and 700 students actively engaged in education and research. Our activities cover almost all the areas of engineering disciplines. Since its foundation in 1949, IIS has worked to bridge the huge gaps that exist between academic disciplines and real-world applications.

Institute of Industrial Science, The University of Tokyo

Related Crystal Formation Articles from Brightsurf:

Getting single-crystal diamond ready for electronics
Researchers from Osaka University and collaborating partners polished single-crystal diamond to near-atomic smoothness without damaging it.

X-rays indicate that water can behave like a liquid crystal
Scientists at Stockholm University have discovered that water can exhibit a similar behavior like a liquid crystal when illuminated with laser light.

Photonic crystal light converter
Spectroscopy is the use of light to analyze physical objects and biological samples.

Higher-order topology found in 2D crystal
The research team took a new approach by using the Josephson junctions to spatially resolve the supercurrent flow and to show that WTe2 does indeed appear to have hinge states and be a higher-order topological insulator.

Hammer-on technique for atomic vibrations in a crystal
Vibrations of atoms in a crystal of the semiconductor gallium arsenide (GaAs) are impulsively shifted to a higher frequency by an optically excited electric current.

Crystal wars
Scientists at The University of Tokyo and Fudan University researched the process of crystallization in which competing structural forms coexist.

Vapor fix lifts up perovskite crystal performance
A facile and mild bromine treatment eliminates surface and bulk defects from perovskites to boost the materials' optoelectronic properties.

Melting a crystal topologically
Physicists at EPFL have successfully melted a very thin crystal of magnetic quasi-particles controllably, as turning ice into water.

The makings of a crystal flipper
Hokkaido University scientists have fabricated a crystal that autonomously flips back and forth while changing its flipping patterns in response to lighting conditions.

Crystal power
Scientists at the US Department of Energy's Argonne National Laboratory have created and tested a single-crystal electrode that promises to yield pivotal discoveries for advanced batteries under development worldwide.

Read More: Crystal Formation News and Crystal Formation Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to