Researchers have discovered brand-new proof that water may transform into a
denser liquid from another sort of liquid.
Researchers from Boston University initially proposed a novel type of water
"phase transition" in a study conducted 30 years ago. But proving the
transition's presence has been difficult because it has been projected to
happen under supercooled settings. This is due to the fact that water
actually prefers to quickly turn into ice at these low temperatures rather
than remain a liquid. Contrary to common examples of phase transitions in
water between a solid or vapour phase and a liquid phase, this liquid-liquid
phase transition is still largely unknown due to its concealed state.
The 1992 theory of a liquid-liquid phase transition is now significantly
strengthened by the new data, which was published in Nature Physics.
Co-author of this work and former member of the original research team at
Boston University, Francesco Sciortino is currently a professor at Sapienza
Università di Roma.
The team has utilized computer simulations to assist understand the
characteristics that, at the microscopic level, separate the two liquids.
They discovered that the water molecules in the high-density liquid organize
themselves into configurations that are referred to as "topologically
complicated," such as a trefoil knot or a Hopf link (think of two links in a
steel chain). Thus, it is argued that the molecules in the high-density
liquid are entangled.
The molecules in the low-density liquid, in contrast, are unentangled
because they mostly form simple rings there.
We now have a brand-new perspective on a research issue that has existed
for thirty years; hopefully, this is only the beginning.
Andreas Neophytou, Chemistry School
The paper's principal author is Andreas Neophytou, a PhD candidate at the
University of Birmingham under the direction of Dr. Dwaipayan Chakrabarti.
He explains, "This understanding has given us an entirely new perspective on
a research subject that has been around for 30 years, and hopefully this is
only the beginning."
In their simulation, the researchers first employed two popular molecular
models of water, followed by a colloidal model of water. The size of a
colloidal particle can be a thousand times that of a water molecule.
Colloids are utilized to monitor and comprehend physical processes that also
happen at the much smaller atomic and molecular length scales because of
their comparatively larger size and slower motions.
"This colloidal model of water gives a magnifying glass into molecular
water, enabling us to grasp the mysteries of water concerning the tale of
two liquids," explains Dr. Chakrabarti, a co-author.
"In this work, we present, for the first time, a perspective of the
liquid-liquid phase transition based on network entanglement principles,"
claims Professor Sciortino. I have no doubt that this study will stimulate
new topologically based theoretical modeling.
The team anticipates that the model they have created will open the door
for fresh research that will support the hypothesis and broaden the
definition of "entangled" liquids to include additional liquids like
silicon.
"This beautiful computational work uncovers the topological basis
underlying the existence of different liquid phases in the same
network-forming substance," says Pablo Debenedetti, professor of chemical
and biological engineering at Princeton University in the US and a leading
authority in this field of study. In doing doing, it "significantly improves
and deepens our understanding of a phenomena that extensive experimental and
computational data increasingly shows is crucial to the physics of that most
important of liquids: water," the author continues.
"With this single paper, Neophytou et al. made several breakthroughs that
will be consequential across diverse scientific fields," says Christian
Micheletti, a professor at the International School for Advanced Studies in
Trieste, Italy, whose current research interest is understanding the impact
of entanglement, especially knots and links, on the static, kinetics, and
functionality of biopolymers. First, a completely new outlook for extensive
research of liquids is provided by their beautiful and experimentally
feasible colloidal model for water. Additionally, they provide extremely
convincing evidence that tracking the kinks and connections in the liquid's
bond network may easily detect phase changes that may elude standard
examination of the local structure of liquids. It is a really potent concept
to look for such intricate details in the relatively abstract space of
routes that run along temporary chemical interactions, and I anticipate that
it will be widely used to research complicated molecular systems.
"Water, one after another, unveils its mysteries," continues Sciortino.
Imagine how lovely it would be to be able to peer into the liquid and watch
the water molecules flash, dance, and trade partners, reorganizing the
hydrogen bond network. This wish may come true with the use of the colloidal
model for water that we suggest.
The EPSRC Centre for Doctoral Training in Topological Design and the
Institute of Advanced Studies at the University of Birmingham, as well as
the Italian Ministero Istruzione Università Ricerca - Progetti di Rilevante
Interest Nazionale, provided funding for the research through the
International Exchanges Award program of the Royal Society.
