Research

Engineers develop real-time membrane imaging for sustainable water filtration

Jeff Zehnder — Tue, 06 Jan 2026 22:34:46 +0000

Engineers develop real-time membrane imaging for sustainable water filtration Jeff Zehnder Tue, 01/06/2026 - 15:34

�鶹��Ѱ��Boulder researchers have introduced a solution to improving the performance of large-scale desalination plants: stimulated Raman scattering (SRS).

Published Dec. 16 in the journal Environmental Science & Technology, the laser-based imaging method allows researchers to observe in real time membrane fouling, a process where unwanted materials such as salts, minerals and microorganisms accumulate on filtration membranes.

Worldwide, 55% of people experience water scarcity at least one month a year and that number is expected to climb to 66% by the end of the century.

Desalination—turning saltwater into fresh water—is critical for communities globally as demand increases.

Modern reverse osmosis (RO) plants make up about 80% of the world’s desalination facilities, placing greater importance on having them run efficiently.

“Reverse osmosis membranes are critical for desalination,” said Juliet Gopinath, professor of electrical, computer and energy engineering and physics. “Our work aims to monitor and provide early warning for membrane fouling.”

RO systems rely on thin polymer membranes to filter out buildup.

A set of three real-time, in-situ calcium sulfate crystal scaling images. The growth of three unique crystal morphologies over time emphasizes the importance of having both the image along side the chemical identification that stimulated Raman spectroscopy provides. (Credit: Lange Simmons and Jasmine Andersen)

This accumulation reduces filtration efficiency and increases both energy use and operating costs for desalination plants.

Detecting fouling early remains one of the biggest challenges in desalination.

“We can learn a lot about materials and molecules by shining light on them,” said Postdoctoral Researcher Jasmine Andersen. “Depending on the type of light you use, you’ll get different light coming back, and that tells you what’s inside the material.”

This principle underlies Raman scattering, where the color—or wavelength—of the scattered light shifts in ways that reveal a material’s molecular structure and composition.

The team used SRS to observe crystal growth on RO membranes, tracking how the molecules vibrated revealing the chemical makeup of the material.

To test the system, researchers observed calcium sulfate and calcium bicarbonate, ions commonly found in seawater. SRS provided both high-speed imaging and chemical identification.

“Watching these crystals form as it happens, getting volumetric data and identifying the chemical all at once is pretty exciting,” Andersen said. “Previously, you could get volume data or chemical identification, but not at the same time.”

Andersen notes this level of insight is something industry tools cannot currently provide.

Supporting sustainable water systems

Understanding what forms on a membrane and when can help operators maximize filtration, notes Professor Emeritus Alan Greenberg, an expert in membrane performance and characterization.

“It is well known that RO desalination plants can be more productive and operate at lower cost if fouling is reduced and cleaning is more efficient,” Greenberg said.

Beyond calcium sulfate, the team expects SRS could help study more complex mixtures of organic, inorganic and biological materials that contribute to fouling in both seawater and brackish water systems.

“As our freshwater resources shrink, we’re going to rely more on desalination,” Andersen said. “If we can make that process more efficient and sustainable, we can help ensure people have reliable access to clean water.”

Key collaborators on this project included Victor Bright, professor of mechanical engineering; Y. Lange Simmons physics doctoral graduate; and Mo Zohrabi, senior research scientist. This project received funding from the Advanced Research Projects Agency-Energy, the National Science Foundation and a �鶹��Ѱ��Boulder Research and Innovation Seed Grant.

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New materials, old physics—the science behind how your winter jacket keeps you warm

Jeff Zehnder — Mon, 05 Jan 2026 15:52:59 +0000

New materials, old physics—the science behind how your winter jacket keeps you warm Jeff Zehnder Mon, 01/05/2026 - 08:52

Winter jackets may seem simple, but sophisticated engineering allows them to keep body heat locked in while staying breathable enough to let out sweat. Read from �鶹��Ѱ��experts Longji Cui and Wan Xiong on The Conversation.

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New window insulation blocks heat, but not your view

Jeff Zehnder — Fri, 12 Dec 2025 19:31:30 +0000

New window insulation blocks heat, but not your view Jeff Zehnder Fri, 12/12/2025 - 12:31

Physicists at �鶹��Ѱ��Boulder have designed a new material for insulating windows that could improve the energy efficiency of buildings worldwide—and it works a bit like a high-tech version of Bubble Wrap.

The team’s material, called Mesoporous Optically Clear Heat Insulator, or MOCHI, comes in large slabs or thin sheets that can be applied to the inside of any window. So far, the team only makes the material in the lab, and it’s not available for consumers. But the researchers say MOCHI is long-lasting and is almost completely transparent.

That means it won’t disrupt your view, unlike many insulating materials on the market today,

“To block heat exchange, you can put a lot of insulation in your walls, but windows need to be transparent,” said Ivan Smalyukh, senior author of the study and a professor of physics at �鶹��Ѱ��Boulder. “Finding insulators that are transparent is really challenging.”

He and his colleagues published their results Dec. 11 in the journal “Science.”

Eldho Abraham, left, and Taewoo Lee, right, hold up a thin sheet of MOCHI affixed to clear plastic.(Photo by Glenn J. Asakawa/�鶹��Ѱ��Boulder)

Shakshi Bhardwaj holds up blocks of MOCHI in different sizes. (Credit: Glenn Asakawa/�鶹��Ѱ��Boulder)

From left to right, Eldho Abraham, Gewei (Gary) Chen, Abram Fluckiger, Taewoo Lee, Keita Richardson, Shiva Singh, Shakshi Bhardwaj, Hanqing Zhao, Ivan Smalyukh, and Alex Adaka. (Credit: Glenn Asakawa/�鶹��Ѱ��Boulder)

Buildings, from single-family homes to office skyscrapers, consume about 40% of all energy generated worldwide. They also leak, losing heat to the outdoors on cold days and absorbing heat when the temperature rises.

Smalyukh and his colleagues aim to slow down that exchange.

The group’s MOCHI material is a silicone gel with a twist: The gel traps air through a network of tiny pores that are many times thinner than the width of a human hair. Those tiny air bubbles are so good at blocking heat that you can use a MOCHI sheet just 5 millimeters thick to hold a flame in the palm of your hand.

“No matter what the temperatures are outside, we want people to be able to have comfortable temperatures inside without having to waste energy,” said Smalyukh, a fellow at the Renewable and Sustainable Energy Institute (RASEI) at �鶹��Ѱ��Boulder.

Bubble magic

Smalyukh said the secret to MOCHI comes down to precisely controlling those pockets of air.
The team’s new invention is similar to aerogels, a class of insulating material that is in widespread use today. (NASA uses aerogels inside its Mars rovers to keep electronics warm).

Like MOCHI, aerogels trap countless pockets of air. But those bubbles tend to be distributed randomly throughout aerogels and often reflect light rather than let it pass through. As a result, these materials often look cloudy, which is why they’re sometimes called “frozen smoke.”

In the new research, Smalyukh and his colleagues wanted to take a different approach to insulation.

To make MOCHI, the group mixes a special type of molecule known as surfactants into a liquid solution. These molecules natural clump together to form thin threads in a process not unlike how oil and vinegar separate in salad dressing. Next, molecules of silicone in the same solution begin to stick to the outside of those threads.

Through a series of steps, the researchers then replace the clumps of detergent molecules with air. That leaves silicone surrounding a network of incredibly small pipes filled with air, which Smalyukh compares to a “plumber’s nightmare.”

In all, air makes up more than 90% of the volume of the MOCHI material.

Trapping heat

Smalyukh said that heat passes through a gas in a process something like a game of pool: Heat energizes molecules and atoms in the gas, which then bang into other molecules and atoms, transferring the energy.

The bubbles in MOCHI material are so small, however, that the gases inside can’t bang into each other, effectively keeping heat from flowing through.

“The molecules don’t have a chance to collide freely with each other and exchange energy,” Smalyukh said. “Instead, they bump into the walls of the pores.”

At the same time, the MOCHI material only reflects about .2% of incoming light.

The researchers see a lot of uses for this clear-but-insulating material. Engineers could design a device that uses MOCHI to trap the heat from sunlight, converting it into cheap and sustainable energy.

“Even when it’s a somewhat cloudy day, you could still harness a lot of energy and then use it to heat your water and your building interior,” Smalyukh said.

You probably won’t see these products on the market soon. Currently, the team relies on a time-intensive process to produce MOCHI in the lab. But Smalyukh believes the manufacturing process can be streamlined. The ingredients his team uses to make MOCHI are also relatively inexpensive, which the physicist said bodes well for turning this material into a commercial product.

For now, the future for MOCHI, like the view through a window coated in this insulating material, looks bright.

Co-authors of the new study include Amit Bhardwaj, Blaise Fleury, Eldo Abraham and Taewoo Lee, postdoctoral research associates in the Department of Physics at �鶹��Ѱ��Boulder. Bohdan Senyuk, Jan Bart ten Hove and Vladyslav Cherpak, former postdoctoral researchers at �鶹��Ѱ��Boulder, also served as co-authors.

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A better band-aid: New 'suspended animation' technology could revolutionize wound care

Jeff Zehnder — Fri, 10 Oct 2025 18:43:52 +0000

A better band-aid: New 'suspended animation' technology could revolutionize wound care Jeff Zehnder Fri, 10/10/2025 - 12:43

Burn your hand on a hot stove and, almost instantly, immune cells within the wound begin producing inflammatory compounds to help clear out dead tissue and fight off infection. In most cases, the swelling abates quickly, and the wound heals within days.

But for the 600,000 or so people in the United States who suffer serious burns each year, the immune response itself can cause problems, with prolonged inflammation tearing through surrounding tissue and increasing risk of scarring, disfigurement and disability.

A team of �鶹��Ѱ��Boulder scientists hopes to minimize such long-term damage by suspending that cellular immune response until the body, or care providers, are better equipped to deal with it.

Funded by a new up-to-$5.8 million, two-year contract from the Advanced Research Projects Agency for Health (ARPA-H), the project could lead to new treatments for a host of serious tissue injuries, from battlefield blast wounds to frostbite and diabetic ulcers. It could be particularly useful for those without immediate access to care.

“The ultimate goal is to help patients have less pain, faster healing and less systemic damage,” said Christopher Bowman, professor of chemical and biological engineering and co-principal investigator on the project. “It could also save lives.”

Suspended animation for cells

The new “Tissue Preservation Under Stress” (TPS) project grew out of a years-long �鶹��Ѱ��Boulder effort, funded by the U.S. Defense Advanced Research Projects Agency (DARPA), to develop novel ways to keep battlefield injuries from worsening as soldiers awaited transport.

An AI rendering of a tardigrade, or 'water bear.' The microscopic animal goes into 'biostasis' to survive extreme temperatures, and served as inspiration for a new wound care technology. Credit: Adobe stock

Since 2018, the �鶹��Ѱ��team has centered their research around a seemingly sci-fi process called “biostasis,” in which certain organisms temporarily shut down cellular processes to survive harsh conditions. For instance, in extremely cold temperatures, a microanimal called a tardigrade, a.k.a. water bear, slows its cellular function to a stand-still. When temperatures warm, the cells awaken from hibernation.

“The big picture idea was that you could possibly put injured tissue in biostasis until transport to a medical facility could occur,” explained Kristi Anseth, professor of chemical and biological engineering and co-principal investigator on the TPS project.

To induce biostasis in mammalian cells, Bowman, and a multidisciplinary team from CU’s BioFrontiers Institute, developed a specialized hydrogel—essentially a biodegradable 3D plastic— which, upon entering cells, spreads out like a net to stop proteins, enzymes and other molecules inside from moving around.

“It’s like freezing without the ice,” said Senior Research Associate Benjamin Fairbanks, who has been working on the technology for years. “It is a completely different way of addressing the problem,” of serious wounds.

Once light is shined on the cells, the hydrogel degrades and normal cellular activity resumes, according to a paper published in the journal Advanced Materials in 2022.

Subsequent studies on simulated skin in the lab show that when the hydrogel material is applied, healing stalls, and once the polymer degrades, healing resumes.
Pilot studies in animals have also shown promise.

“You basically protect the tissue from its own responses until the initial trauma passes and then bring the cells back to full activity,” said Bowman.

A smarter band-aid

Christopher Bowman, research assistant Maria Lemon, seated, senior research associate Ben Fairbanks, in background, and doctoral candidate Jessica Stelzel. (Photo by Glenn J. Asakawa/University of Colorado)

ARPA-H was founded in 2022 with a mission to fast-track “high-impact solutions to society’s most challenging health problems.”

In its announcement about the new TPS contract, the agency named traumatic tissue injuries among those major challenges.

“Despite advancement in wound care, millions of Americans lack immediate access to specialized medical facilities, increasing the risk of chronic wounds or death.”

Studies show burns account for as many as 20% of battlefield injuries too, with most caused by blasts from explosive devices. In those cases, prolonged inflammation can make it hard to preserve limbs. Biostasis could potentially make it easier, suspects Bowman.

More research is necessary before the technology is ready for use in people, but the potential applications are broad.

Anseth and Bowman envision a day when hydrogel-infused bandages could be used by soldiers in the field, carried on mountaineering expeditions (where frostbite is common), or used in remote health clinics, where resources for treating serious burns or wounds are limited and patients must often be transported.

It may also have applications in cancer treatment someday, to minimize the impact of burns from radiation therapy.

The new infusion of federal dollars could make these possibilities come sooner.

“What’s really special about this funding is that it bridges the gap between fundamental science and clinical application and it makes you think big,” said Anseth. “It’s exciting to be a part of that.”

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New quantum physics and AI-powered microchip design software awarded grants

Jeff Zehnder — Thu, 24 Jul 2025 19:33:26 +0000

New quantum physics and AI-powered microchip design software awarded grants Jeff Zehnder Thu, 07/24/2025 - 13:33

Semiconductors—substances that can selectively conduct or block electricity—have been dubbed the “brains of modern electronics.” They form the building blocks of the chips that power electronic devices from laptops to smartphones and tablets to sports watches.

But semiconductors generate heat when they’re working, and they can easily get too hot, which hurts their performance and can damage them. While smaller chips are denser and more efficient at processing, they are harder to keep cool because of their size.

Sanghamitra Neogi, an associate professor in the Ann and H.J. Smead Aerospace Engineering Sciences department, is exploring ways to protect semiconductors and microchips from heat damage. She specializes in nanoscale semiconductors, which are so tiny their parts are measured in nanometers (billionths of a meter).

Sanghamitra Neogi speaks about her startup, AtomTCAD Inc., at �鶹��Ѱ��Boulder's Ascent Deep Tech Community Showcase on June 25, 2025. (Credit: Casey Cass/�鶹��Ѱ��Boulder)

Neogi and her research group, CUANTAM Laboratory, have developed a sophisticated software called AtomThermCAD that can predict how the materials in a microchip generate and respond to heat, which determines whether the chip will ultimately fail from overheating. AtomThermCAD is short for Atom-to-Device Thermal Computer Aided Design software for nanometer-scale semiconductor devices. The research behind this software was primarily supported by a $1 million DARPA MTO Thermonat grant awarded between 2023 and 2025.

Earlier this year, Neogi launched a startup to bring the software to market for semiconductor manufacturers and other customers. To kickstart her new company, AtomTCAD Inc., Neogi received $150,000 in recent grant funding from the state’s Office of Economic Development and International Trade, or OEDIT, matched by another $50,000 from Venture Partners at �鶹��Ѱ��Boulder, which helps �鶹��Ѱ��faculty and researchers turn their discoveries into startups and partnerships through funding and entrepreneurial support.

The grant from OEDIT was an advanced industries proof-of-concept grant for researchers in advanced industries. Managed by OEDIT’s Global Business Development division, this funding is intended to accelerate innovation, promote public-private partnerships and encourage commercialization of products and services to strengthen Colorado’s economy.

OEDIT Executive Director Eve Lieberman said that Neogi’s work will benefit the entire semiconductor industry, a rapidly growing segment of Colorado’s economy.

“Dr. Neogi’s research addresses one of the industry’s toughest challenges by improving heat management at the nanoscale, which boosts chip performance and supports the growth of Colorado’s advanced technology sector,” Lieberman said.

Chip designers use software like Neogi’s to test their designs without needing to actually build the chips. But unlike most chip design software, AtomThermCAD uses AI-accelerated quantum physics calculations to model the semiconductors and their components at an atomic level so it can accurately predict whether semiconductors or transistors too small to be seen by the naked eye will overheat.

The software could accelerate technological advancement by saving chip designers months, if not years, of time they previously had to spend developing and testing their designs.

Neogi drew on her expertise in physics and quantum technology to develop the software. She said as microchip components get smaller and smaller, approaching the level of individual atoms, researchers need to look to quantum physics to understand how the components behave.

Neogi also feels her approach could have applications beyond microchip development.

“What we developed is a method where you can model the thermal phenomena of any kind of nanoscale tech device,” she said. “Beyond microchips, it could be nanoscale medical devices and implants inside your body, or even drug delivery systems.”

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Faster, cleaner, better: revolutionary water treatment

Jeff Zehnder — Thu, 17 Jul 2025 19:50:56 +0000

Faster, cleaner, better: revolutionary water treatment Jeff Zehnder Thu, 07/17/2025 - 13:50

Jeff Zehnder

Anthony Straub is making revolutionary advances in water purification for life on Earth and in space.

Using nanoscale membranes—thinner than 1/100th the width of a human hair—Straub has developed a technology that could significantly improve conventional water treatment, microchip production, and desalination.

His efforts are receiving major recognition from the National Science Foundation, which is honoring Straub with a CAREER Award, a five-year, $550,000 grant to advance his research.

“We’re excited about this work,” said Straub, an assistant professor in the Department of Civil, Environmental and Architectural Engineering at the �鶹��Ѱ��. “For desalination, switching to these membranes could produce 50 times cleaner water while lasting much longer. It’s really a big deal.”

Membrane technology has been in use for water purification for over five decades. It works well for many applications, but filter degradation is a problem, and even at peak conditions, some contaminants can still pass through the membranes.

“Current membranes are very hard to clean,” Straub said. “A major advance of this new membrane is you can expose it to concentrated bleach and cleaning chemicals. It also removes almost every impurity from water – salts, dissolved metals, and organic contaminants like hormones, PFAS, and pharmaceuticals.”

In the new process, Straub traps a tiny layer of air inside a porous membrane. Using pressure, water is forced against the membrane until it evaporates and recondenses on the other side of the air layer. The technology requires no additional electricity or heat and operates with pumps already used in water systems.

“It’s reimagining distillation. Thermal distillation – essentially boiling water – has been used to purify water for centuries, but it is really energy intensive. We’re laying the groundwork for distillation with pressure as the driving force, and it is 10 times more energy efficient,” Straub said.

The technology has advanced beyond the initial research phase. Straub has conducted successful small-scale tests and has two provisional patents on the design. Last year, he co-founded a spinoff company and received a grant from NASA for a prototype purification system for astronauts to use on a future Moon base.

Design of ultrathin air-trapping membranes for pressure-driven vapor transport. For more details, read "Pressure-driven distillation using air-trapping membranes for fast and selective water purification" in the journal Science Advances.

“There were papers discussing this process; the theoretical foundations were there. Our major advance was demonstrating it successfully. We had to understand how to develop materials with really small pore sizes that can trap air,” Straub said.

A major focus of the future work will be better analysis and modeling of the process.

“This technology is transitioning to applied use, but some aspects of the process aren’t as well understood. That’s very important for end users, to know how this design works, how the transport happens. We have some models, but they’re for very idealized systems, which isn’t how things work in the real world,” he said.

Beyond traditional water treatment, the process has drawn significant interest from microchip producers. Semiconductor wafers are manufactured in clean rooms, and ultrapure water is needed to rinse wafers and wash away residue produced during chip etching.

Even the tiniest water impurities can damage the chips, so water must be purified to levels far beyond what is needed for regular drinking water, requiring an expensive, elaborate system. Straub’s technology would dramatically simplify the process and lower costs.

“This is a huge potential market. Companies currently use a treatment process involving at least 14 different steps, and they avoid shutting down the machines because they’re worried that particles could enter the production line,” he said.

In addition to advancing research, Straub is also developing an education and outreach component as part of the CAREER award. Collaborating with a faculty colleague in the mechanical engineering department, Daniel Knight, the pair are developing a project-based water treatment course that will be used in rural K-12 schools across Colorado.

“Lots of these schools are in areas where they don’t have enough water, so this is really important,” Straub said.

He hopes the outreach will be both educational and promote career opportunities for the next generation of water engineers.

“My parents grew up in Latin America in underserved areas,” he said. “In undergrad, I was drawn to improve water treatment in low resource settings, and I caught the research bug. I want to encourage other people, too. It’s about making the world a better place.”

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Advancing super strong and lightweight next generation carbon-based materials

Jeff Zehnder — Fri, 30 May 2025 02:10:31 +0000

Advancing super strong and lightweight next generation carbon-based materials Jeff Zehnder Thu, 05/29/2025 - 20:10

Jeff Zehnder

Materials researchers are getting a big boost from a new database created by a team of researchers led by Hendrik Heinz.

A professor of chemical and biological engineering at the �鶹��Ѱ��, Heinz advanced a major initiative to create a public database, available online to all researchers, that contains over 2,000 carbon nanotube stress-strain curves and failure properties.

“This data sharing is important. It allows the scientific community to build on and expand. Instead of someone spending a year figuring out the mechanics of a particular carbon nanostructure in experiments, they can use this database. You’ll have the results in one hour,” said Heinz, who is also a faculty member in the materials science and engineering program.

The announcement came in a new paper published in the Proceedings of the National Academy of Sciences.

Carbon nanotubes and associated graphitic structures are strong and lightweight engineered materials with great potential in multiple sectors, including aviation, automobiles, and electronics. They were first discovered in the 1970s, but their tiny size – the engineering is conducted at the atomic scale – has made them difficult to study, until now.

“Carbon nanotubes and graphene can be stronger than steel,” Heinz said. “They will be really important for next generation cars, planes, and spacecraft, but we have to understand their chemistry and physics.”

Working with a team that included researchers from the Air Force Research Laboratory, Johns Hopkins University, Texas A&M University, and the University of California San Diego, the group built computational models using artificial intelligence to develop high quality predictions of mechanical properties of different carbon nanotube materials.

How will a stress-strain and failure database assist researchers? With any material, it is necessary for product designers to understand their strength and ability to withstand adverse conditions and manipulation.

“This is a problem where data science was really able to help. Materials science usually has a problem of sparse data and not enough data points. This model changes that. Now someone can take a 3-dimensional structure and change the morphology or introduce a defect and it will be really easy to test,” Heinz said.

The project grew out of a National Science Foundation initiative called “Harnessing the Data Revolution” and represents six years of research.

“People have made claims that they had a 3D structures database for carbon nanotubes, but they had no attached mechanical properties or conductivity or anything useful,” Heinz said “You can’t learn anything from that. This is the first database structures and the properties, and it’s available to a broad community."

The database is available on both figShare and Github.

In addition to Heinz, co-authors of the PNAS paper include Jordan Winetrout (MatSciPhD’24) from �鶹��Ѱ��Boulder; Professor Yusu Wang, Zilu Li, and Qi Zhao, all from UCSD; Assistant Professor Vinu Unnikrishnan and Landon Gaber from Texas A&M University; Vikas Varshney from AFRL; and Associate Professor Yanxun Xu from Johns Hopkins University.

Materials researchers are getting a big boost from a new database created by a team of researchers led by Hendrik Heinz. The initiative, now available online to all researchers, is a database containing over 2,000 carbon nanotube stress-strain curves and failure properties.

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New discovery shows how molecules can mute heat like music

Jeff Zehnder — Tue, 06 May 2025 15:43:01 +0000

New discovery shows how molecules can mute heat like music Jeff Zehnder Tue, 05/06/2025 - 09:43

Imagine you are playing the guitar—each pluck of a string creates a sound wave that vibrates and interacts with other waves.

Now shrink that idea down to a small single molecule, and instead of sound waves, picture vibrations that carry heat.

Ultra-high vacuum scanning probe setup modified by the Cui Research Group to conduct thermal microscopy experiments.

A team of engineers and materials scientists in the Paul M. Rady Department of Mechanical Engineering at �鶹��Ѱ��Boulder has recently discovered that these tiny thermal vibrations, otherwise known as phonons, can interfere with each other just like musical notes—either amplifying or canceling each other, depending on how a molecule is "strung" together.

Phonon interference is something that’s never been measured or observed at room temperature on a molecular scale. But this group has developed a new technique that has the power to display these tiny, vibrational secrets.

The breakthrough study was led by Assistant Professor Longji Cui and his team in the Cui Research Group. Their work, funded by the National Science Foundation in collaboration with researchers from Spain (Instituto de Ciencia de Materiales de Madrid, Universidad Autónoma de Madrid), Italy (Istituto di Chimica dei Composti Organometallici) and the �鶹��Ѱ��Boulder Department of Chemistry, was recently published in the journal Nature Materials.

The group says their findings will help researchers around the world gain a better understanding of the physical behaviors of phonons, the dominant energy carriers in all insulating materials. They believe one day, this discovery can revolutionize how heat dissipation is managed in future electronics and materials.

“Interference is a fundamental phenomenon,” said Cui, who is also affiliated with the Materials Science and Engineering Program and the Center for Experiments on Quantum Materials. “If you have the capability to understand interference of heat flow at the smallest level, you can create devices that have never been possible before.”

The world’s strongest set of ears

Cui says molecular phononics, or the study of phonons in a molecule, has been around for quite some time as a primarily theoretical discussion. But you need some pretty strong ears to “listen” to these molecular melodies and vibrations first-hand, and that technology just simply hasn’t existed.

A sneak peek into the ultra-high vacuum scanning probe microscopy setup used to conduct molecular measurements.

That is, until Cui and his team stepped in.

The group designed a thermal sensor smaller than a grain of sand or even a sawdust particle. This little probe is special: it features a record-breaking resolution that allows them to grab a molecule and measure phonon vibration at the smallest level possible.

Using these specially designed miniature thermal sensors, the team studied heat flow through single molecular junctions and found that certain molecular pathways can cause destructive interference—the clashing of phonon vibrations to reduce heat flow.

Sai Yelishala, a PhD student in Cui’s lab and lead author of the study, said this research using their novel scanning thermal probe represents the first observation of destructive phonon interference at room temperature.

In other words, the team has unlocked the ability to manage heat flow at the scale where all materials are born: a molecule.

“Let’s say you have two waves of water in the ocean that are moving towards each other. The waves will eventually crash into each other and create a disturbance in between,” Yelishala said. “That is called destructive interference and that is what we observed in this experiment. Understanding this phenomenon can help us suppress the transport of heat and enhance the performance of materials on an extremely small and unprecedented scale.”

Tiny molecules, vast potential

Developing the world’s strongest set of ears to measure and document never-before-seen phonon behavior is one thing. But just what exactly are these tiny vibrations capable of?

PhD student and lead author of the study Sai Yelishala (right), along with Postdoctoral Associate and second author Yunxuan Zhu (left). Both are members of the Cui Research Group led by Assistant Professor Longji Cui.

“This is only the beginning for molecular phononics,” said Yelishala. “New-age materials and electronics have a long list of concerns when it comes to heat dissipation. Our research will help us study the chemistry, physical behavior and heat management in molecules so that we can address these concerns.”

Take an organic material, like a polymer, as an example. Its low thermal conductivity and susceptibility to temperature changes often poses great risks, such as overheating and degradation.

Maybe one day, with the help of phonon interference research, scientists and engineers can develop a new molecular design. One that turns a polymer into a metal-like material that can harness constructive phonon vibrations to enhance thermal transport.

The technique can even play a large role in areas like thermoelectricity, otherwise known as the use of heat to generate electricity. Reducing heat flow and suppressing thermal transport in this discipline can enhance the efficiency of thermoelectric devices and pave the way for clean energy usage.

The group says this study is just the tip of the iceberg for them, too. Their next projects and collaborations with �鶹��Ѱ��Boulder chemists will expand on this phenomenon and use this novel technique to explore other phononic characteristics on a molecular scale.

“Phonons travel virtually in all materials,” Yelishala said. “Therefore we can guide advancements in any natural and artificially made materials at the smallest possible level using our ultra-sensitive probes.”

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Bay earns major Air Force Young Investigator award

Jeff Zehnder — Thu, 27 Mar 2025 22:35:28 +0000

Bay earns major Air Force Young Investigator award Jeff Zehnder Thu, 03/27/2025 - 16:35

Assistant Professors Kōnane Bay and Ankur Gupta from �鶹��Ѱ��Boulder’s Department of Chemical and Biological Engineering have been honored with the 2025 Air Force Office of Scientific Research (AFOSR) Young Investigator Program Award.

Each received a $450,000, three-year grant to advance research relevant to the Air Force. The program, offered by the Air Force Research Laboratory, supports early-career scientists and engineers with “exceptional ability and promise for conducting basic research,” according to the AFOSR.

“This is among the most prestigious awards given to junior faculty, and to have both Ankur and Kōnane receive it in the same year is a remarkable testimony to their impressive achievements and very high potential for making future advances,” said Professor Ryan Hayward, chair of the department.

Kōnane Bay, self-healing, innovative materials

Bay says the next generation of polymer materials—materials with long chains of molecules like plastics, rubber and proteins—will need advanced features, such as the ability to repair themselves. While engineering synthetic polymers with these properties is challenging, biofilm-forming bacteria are promising as they use internal material factories to produce polymers on demand to survive changes in the surroundings.

“I am grateful to receive this award which will allow our lab to harness nature to create novel engineered living materials,” Bay said.

The award will support Bay and her team at the Huli Materials Lab in using biofilm-forming bacteria to develop new polymeric materials. The project combines 3D printing with bacteria’s natural movement to control the mechanical properties of biofilm-based synthetic polymers. The findings could lead to self-healing materials that can change shape, with applications in aerospace, soft robotics, and protective coatings.

Bay recently also received a prestigious CAREER Award, a $675,000, five-year grant from the National Science Foundation. The funding will advance her work in characterization of polymer thin film.

Ankur Gupta, more precise chemical sensors

Imagine being able to organize tiny particles as small as one-twentieth the thickness of a human hair.

Gupta’s research aims to do just that. He and his team in the Laboratory of Interfaces, Flow and Electrokinetics (LIFE) study how these tiny particles form patterns through chemical reactions and diffusion. The researchers aim to control this process to develop materials that detect microscopic changes in the air, paving the way for advanced chemical sensors that identify subtle chemical shifts and improve safety.

“It’s an honor for us to receive this award, especially given its prestige and selectivity,” Gupta said. “This recognition is a testament to the hard work of my current and past group members, and I am grateful for the opportunity to work with them.”

The $450,000 three-year grant will support a graduate student and cover travel expenses.

In 2024, Gupta was honored with the Johannes Lyklema Early Career Award in electrokinetics. He was also selected for the prestigious “35 Under 35” award from the American Institute of Chemical Engineers in 2023.

That same year Gupta also received a $517,000, five-year National Science Foundation CAREER Award, to study how ions move through porous materials. His research will help design improved porous materials for more efficient desalination and renewable energy storage.

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Aircrafts of the future: Boosting aerodynamic performance by engineered surface vibrations

Jeff Zehnder — Mon, 24 Mar 2025 16:54:49 +0000

Aircrafts of the future: Boosting aerodynamic performance by engineered surface vibrations Jeff Zehnder Mon, 03/24/2025 - 10:54

Jeff Zehnder

“This is probably the most radical conceptual advancement for airplanes since the replacement of propellers with jets.” – M.I. Hussein

Mahmoud Hussein is not pulling punches about the potential impact of a major aerospace materials research project.

As the principal investigator of a $7.5 million, five-year Department of Defense Office of Naval Research (ONR) Multidisciplinary University Research Initiative (MURI), Hussein is leading an effort to reshape the fundamental character of fluid-structure interactions to reduce drag on high-speed aerospace vehicles—the focus of the project.

“Since the dawn of aviation, aircraft design has been based on the premise of shaping the surface of the vehicle to create lift and minimize drag. Our team is pursuing a new paradigm where the phononic properties, or intrinsic vibrations, of a surface or subsurface provide an additional pathway to interact with the airflow, to enhance the vehicle performance in an unprecedented manner,” said Hussein, the Alvah and Harriet Hovlid Professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the �鶹��Ѱ��.

Hussein also has a courtesy appointment in the Department of Physics and an affiliation with the Materials Science and Engineering Program.

MURI Partners

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Mahmoud I. Hussein
Professor & Principal Investigator
Armin Kianfar
Post-Doctoral Associate
Adam Harris
PhD Student

University of Maryland

Christoph Brehm
Associate Professor

Johns Hopkins University

Kevin Hemker
Professor

Purdue University

Joseph Jewell
Associate Professor

Applied Physics Laboratory

Keith Caruso
Principal Staff Engineer
Ken Kane
Researcher

University of Kentucky

Alexandre Martin
Professor

Case Western Reserve University

Bryan Schmidt
Assistant Professor

Office of Naval Research (Program Directors)

Eric Marineau
Eric Wuchina

Phononic Subsurfaces

Turbulent airflow is detrimental to the fuel economy and the surface temperature of aircrafts as they soar through the atmosphere. This research aims to mitigate the transition to turbulence using phononic subsurfaces (PSubs) – synthetic designed materials affixed beneath the surface of a wing or vehicle body that passively manipulate small-amplitude vibrations, and by extension flow fluctuations, point-by-point along the surface.

Turbulence and Fuel Economy

Passenger planes consume over 10,000 gallons of jet fuel on a single cross-country trip, so improvements in fuel economy could lead to big savings for airlines. The potential in hypersonic crafts is even more dramatic.

Hypersonic vehicles travel at velocities at least five times the speed of sound. The turbulence that results from such speeds causes the surface of the vehicles to heat up to thousands of degrees, requiring they be constructed of exotic, expensive materials.

“By introducing a phononic subsurface to precisely shape the vibrations along the surface, we can alter the way the air interacts with the vehicle such that we ultimately don’t need to come up with exceedingly high-temperature-resistant materials,” Hussein said. “We’re passively manipulating instabilities in air flow in a manner that is favorable in the boundary layer where the vehicle meets the surrounding air.”

2015 to Today

The concept of PSubs was discovered by Hussein. The work began from a collaboration over 15 years ago between Hussein and then �鶹��Ѱ��Boulder Professor Sedat Biringen, who died in 2020. As leaders in the newly-born research area of phononics and the longstanding field of fluid dynamics, respectively, they worked together to theoretically demonstrate–for the first time–a way to manipulate phonons to improve the efficiency of flight, with tremendous potential for the aerospace industry and prospects for application to water vessels as well.

Recently Hussein gathered a team of experts from across the country to take the concept of PSubs to the next level with this hypersonics MURI grant. Over the duration of the project, the group will develop high-fidelity models and fabricate functional prototypes to effectively characterize and demonstrate the technology in high-speed wind tunnels.

“We’re most confident about this endeavor, because the idea is rooted in fundamental science marrying–in quite a sophisticated fashion–fluid dynamics with condensed matter physics as well as with the emerging field of elastic metamaterials,” Hussein said.

“This is probably the most radical conceptual advancement for airplanes since the replacement of propellers with jets.” – Mahmoud Hussein is not pulling punches about the potential impact of a major aerospace materials research project.

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