In a groundbreaking revelation, scientists have discovered an extraordinary phenomenon called quantum friction that governs the flow of water on a surface of carbon atoms, known as graphene.
This extraordinary behavior, which was previously only a theoretical prediction, has now been experimentally demonstrated by an international team of researchers.
Their findings, published in Nature Nanotechnology on June 22, 2023, could revolutionize water purification, desalination processes, and even pave the way for liquid-based computers.
For the past two decades, scientists have been intrigued by the peculiar behavior of water near carbon surfaces.
It appeared to flow at much higher speeds than expected, defying conventional flow theories. Additionally, water exhibited unusual arrangements such as square ice.
Now, researchers from the Max Planck Institute for Polymer Research of Mainz, the Catalan Institute of Nanoscience and Nanotechnology (ICN2), and the University of Manchester have shed light on this mystery.
Traditionally, liquids, like water, consist of randomly moving molecules that collide with one another. Solids, on the other hand, have neatly arranged atoms surrounded by a cloud of electrons.
The interaction between solids and liquids was believed to occur solely through collisions between the liquid’s molecules and the solid’s atoms, with the liquid molecules oblivious to the solid’s electrons.
However, a groundbreaking theoretical study proposed that at the interface of water and carbon, the liquid’s molecules and the solid’s electrons exert forces on each other, resulting in a slowdown of the liquid flow—termed quantum friction.
“We have now employed laser technology to observe quantum friction in action,” explains Dr. Nikita Kavokine, the lead author of the study and a researcher at the Max Planck Institute in Mainz and the Flatiron Institute in New York.
The research team focused on graphene—a single layer of carbon atoms arranged in a honeycomb pattern.
By employing ultrashort red laser pulses, they instantaneously heated the graphene’s electron cloud and monitored its cooling using terahertz laser pulses, which are sensitive to the temperature of the graphene electrons.
This novel technique, known as optical pump—terahertz probe (OPTP) spectroscopy, provided valuable insights into the behavior of water on the graphene surface.
To their astonishment, the researchers discovered that the electron cloud cooled more rapidly when the graphene was immersed in water.
However, immersing the graphene in ethanol had no discernible effect on the cooling rate.
"This finding suggested that the water-carbon interaction is distinct, but we needed to understand the underlying mechanism," adds Kavokine.
After extensive theoretical analysis, the researchers concluded that quantum friction between water and graphene could explain the experimental observations.
The Synchronization of Vibrations Unveils the Extraordinary Nature of Water
Professor Klaas-Jan Tielrooij from ICN2 and TU Eindhoven remarks, "The carrier dynamics of graphene continue to surprise us with unexpected mechanisms, as evidenced by this study involving the interaction between solid and liquid with the ubiquitous presence of water."
The synchronicity between water’s vibrations, referred to as hydrons, and graphene’s electron vibrations, known as plasmons, facilitates enhanced heat transfer between the two through a phenomenon called resonance.
These experimental results affirm the fundamental principles of solid-liquid quantum friction, opening up new possibilities in filtration and desalination processes.
Quantum friction can be harnessed to fine-tune the permeation properties of nanoporous membranes, revolutionizing water purification and desalination technologies.
Xiaoqing Yu, the first author of the study and a Ph.D. student at the Max Planck Institute in Mainz, highlights the broader implications: "Our findings not only captivate physicists but also hold significant potential for advancements in electrocatalysis and photocatalysis at the solid-liquid interface."
The successful realization of this discovery was the result of the convergence of an experimental system, a measurement tool, and a theoretical framework, which are rarely harmonized.
The next critical challenge is to achieve precise control over water-electron interactions.
"Our vision is to manipulate quantum friction at will," envisions Kavokine.
"This breakthrough could pave the way for more efficient water filtration processes and potentially revolutionize the world of fluid-based computing."
In conclusion, the remarkable phenomenon of quantum friction, observed at the interface of water and graphene, promises transformative advancements in various fields.
By unraveling the mysteries of water behavior on carbon surfaces, scientists have taken a significant step towards refining water purification techniques and exploring the realm of fluid-based computing.
As research continues, the future holds tremendous potential for harnessing the power of quantum friction in our quest for sustainable solutions and technological innovations.
Quantum friction is a phenomenon that occurs at the interface between a liquid, such as water, and a solid surface made of carbon atoms, like graphene. It refers to the interaction between the liquid’s molecules and the solid’s electrons, which results in a slowing down of the liquid flow. This behavior, which defies conventional flow theories, has been experimentally observed and is known to have significant implications in various applications.
The discovery of quantum friction between water and graphene was made through a combination of theoretical predictions and experimental studies. Researchers used advanced techniques, including optical pump—terahertz probe (OPTP) spectroscopy, to observe the behavior of water on graphene surfaces. By monitoring the cooling rate of the graphene’s electron cloud when immersed in water, they found that the cooling was faster compared to when the graphene was immersed in ethanol, indicating the presence of quantum friction.
Researchers aim to gain control over quantum friction between water and graphene, with the ultimate goal of being able to switch it on and off at will. The ability to manipulate quantum friction would have far-reaching implications, including the development of smarter water filtration processes and the potential for fluid-based computers. While it remains a challenge, ongoing research aims to uncover methods to achieve precise control over water-electron interactions.
While the initial focus has been on the interaction between water and graphene, the concept of quantum friction could potentially be applicable to other liquids and solid surfaces as well. Further research is necessary to explore the behavior of different liquids and their interactions with various types of carbon surfaces or other materials. Such investigations may uncover additional insights and applications beyond the current scope of understanding.
The discovery of quantum friction opens up new avenues for technological advancements. It has the potential to revolutionize water purification methods, leading to cleaner and more accessible water sources. Moreover, the ability to manipulate quantum friction could have implications for the development of fluid-based computers, where the flow and interaction of liquids with specific surfaces could be utilized for computing purposes. As research progresses, further possibilities and applications of quantum friction are expected to emerge.