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    Creeping crystals: Scientists observe “salt creep” at the single-crystal scale

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    Salt creeping, a phenomenon that occurs in both natural and industrial processes, describes the collection and migration of salt crystals from evaporating solutions onto surfaces. Once they start collecting, the crystals climb, spreading away from the solution. This creeping behavior, according to researchers, can cause damage or be harnessed for good, depending on the context. New research published June 30 in the journal Langmuir is the first to show salt creeping at a single-crystal scale and beneath a liquid’s meniscus.“The work not only explains how salt creeping begins, but why it begins and when it does,” says Joseph Phelim Mooney, a postdoc in the MIT Device Research Laboratory and one of the authors of the new study. “We hope this level of insight helps others, whether they’re tackling water scarcity, preserving ancient murals, or designing longer-lasting infrastructure.”The work is the first to directly visualize how salt crystals grow and interact with surfaces underneath a liquid meniscus, something that’s been theorized for decades but never actually imaged or confirmed at this level, and it offers fundamental insights that could impact a wide range of fields — from mineral extraction and desalination to anti-fouling coatings, membrane design for separation science, and even art conservation, where salt damage is a major threat to heritage materials.In civil engineering applications, for example, the research can help explain why and when salt crystals start growing across surfaces like concrete, stone, or building materials. “These crystals can exert pressure and cause cracking or flaking, reducing the long-term durability of structures,” says Mooney. “By pinpointing the moment when salt begins to creep, engineers can better design protective coatings or drainage systems to prevent this form of degradation.”For a field like art conservation, where salt can be devastating to murals, frescoes, and ancient artifacts, often forming beneath the surface before visible damage appears, the work can help identify the exact conditions that cause salt to start moving and spreading, allowing conservators to act earlier and more precisely to protect heritage objects.The work began during Mooney’s Marie Curie Fellowship at MIT. “I was focused on improving desalination systems and quickly ran into [salt buildup as] a major roadblock,” he says. “[Salt] was everywhere, coating surfaces, clogging flow paths, and undermining the efficiency of our designs. I realized we didn’t fully understand how or why salt starts creeping across surfaces in the first place.”That experience led Mooney to team up with colleagues to dig into the fundamentals of salt crystallization at the air–liquid–solid interface. “We wanted to zoom in, to really see the moment salt begins to move, so we turned to in situ X-ray microscopy,” he says. “What we found gave us a whole new way to think about surface fouling, material degradation, and controlled crystallization.”The new research may, in fact, allow better control of a crystallization processes required to remove salt from water in zero-liquid discharge systems. It can also be used to explain how and when scaling happens on equipment surfaces, and may support emerging climate technologies that depend on smart control of evaporation and crystallization.The work also supports mineral and salt extraction applications, where salt creeping can be both a bottleneck and an opportunity. In these applications, Mooney says, “by understanding the precise physics of salt formation at surfaces, operators can optimize crystal growth, improving recovery rates and reducing material losses.”Mooney’s co-authors on the paper include fellow MIT Device Lab researchers Omer Refet Caylan, Bachir El Fil (now an associate professor at Georgia Tech), and Lenan Zhang (now an associate professor at Cornell University); Jeff Punch and Vanessa Egan of the University of Limerick; and Jintong Gao of Cornell.The research was conducted using in situ X-ray microscopy. Mooney says the team’s big realization moment occurred when they were able to observe a single salt crystal pinning itself to the surface, which kicked off a cascading chain reaction of growth.“People had speculated about this, but we captured it on X-ray for the first time. It felt like watching the microscopic moment where everything tips, the ignition points of a self-propagating process,” says Mooney. “Even more surprising was what followed: The salt crystal didn’t just grow passively to fill the available space. It pierced through the liquid-air interface and reshaped the meniscus itself, setting up the perfect conditions for the next crystal. That subtle, recursive mechanism had never been visually documented before — and seeing it play out in real time completely changed how we thought about salt crystallization.”The paper, “In Situ X-ray Microscopy Unraveling the Onset of Salt Creeping at a Single-Crystal Level,” is available now in the journal Langmuir. Research was conducted in MIT.nano.  More

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      in Security

      Coffee fix: MIT students decode the science behind the perfect cup

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      Elaine Jutamulia ’24 took a sip of coffee with a few drops of anise extract. It was her second try.“What do you think?” asked Omar Orozco, standing at a lab table in MIT’s Breakerspace, surrounded by filters, brewing pots, and other coffee paraphernalia.“I think when I first tried it, it was still pretty bitter,” Jutamulia said thoughtfully. “But I think now that it’s steeped for a little bit — it took out some of the bitterness.”Jutamulia and current MIT senior Orozco were part of class 3.000 (Coffee Matters: Using the Breakerspace to Make the Perfect Cup), a new MIT course that debuted in spring 2024. The class combines lectures on chemistry and the science of coffee with hands-on experimentation and group projects. Their project explored how additives such as anise, salt, and chili oil influence coffee extraction — the process of dissolving flavor compounds from ground coffee into water — to improve taste and correct common brewing errors.Alongside tasting, they used an infrared spectrometer to identify the chemical compounds in their coffee samples that contribute to flavor. Does anise make bitter coffee smoother? Could chili oil balance the taste?“Generally speaking, if we could make a recommendation, that’s what we’re trying to find,” Orozco said.A three-unit “discovery class” designed to help first-year students explore majors, 3.000 was widely popular, enrolling more than 50 students. Its success was driven by the beverage at its core and the class’s hands-on approach, which pushes students to ask and answer questions they might not have otherwise.For aeronautics and astronautics majors Gabi McDonald and McKenzie Dinesen, coffee was the draw, but the class encouraged them to experiment and think in new ways. “It’s easy to drop people like us in, who love coffee, and, ‘Oh my gosh, there’s this class where we can go make coffee half the time and try all different kinds of things?’” McDonald says.Percolating knowledgeThe class pairs weekly lectures on topics such as coffee chemistry, the anatomy and composition of a coffee bean, the effects of roasting, and the brewing process with tasting sessions — students sample coffee brewed from different beans, roasts, and grinds. In the MIT Breakerspace, a new space on campus conceived and managed by the Department of Materials Science and Engineering (DMSE), students use equipment such as a digital optical microscope to examine ground coffee particles and a scanning electron microscope, which shoots beams of electrons at samples to reveal cross-sections of beans in stunning detail.Once students learn to operate instruments for guided tasks, they form groups and design their own projects.“The driver for those projects is some question they have about coffee raised by one of the lectures or the tasting sessions, or just something they’ve always wanted to know,” says DMSE Professor Jeffrey Grossman, who designed and teaches the class. “Then they’ll use one or more of these pieces of equipment to shed some light on it.”Grossman traces the origins of the class to his initial vision for the Breakerspace, a laboratory for materials analysis and lounge for MIT undergraduates. Opened in November 2023, the space gives students hands-on experience with materials science and engineering, an interdisciplinary field combining chemistry, physics, and engineering to probe the composition and structure of materials.“The world is made of stuff, and these are the tools to understand that stuff and bring it to life,” says Grossman. So he envisioned a class that would give students an “exploratory, inspiring nudge.”“Then the question wasn’t the pedagogy, it was, ‘What’s the hook?’ In materials science, there are a lot of directions you could go, but if you have one that inspires people because they know it and maybe like it already, then that’s exciting.”Cup of ambitionThat hook, of course, was coffee, the second-most-consumed beverage after water. It captured students’ imagination and motivated them to push boundaries.Orozco brought a fair amount of coffee knowledge to the class. In 2023, he taught in Mexico through the MISTI Global Teaching Labs program, where he toured several coffee farms and acquired a deeper knowledge of the beverage. He learned, for example, that black coffee, contrary to general American opinion, isn’t naturally bitter; bitterness arises from certain compounds that develop during the roasting process.“If you properly brew it with the right beans, it actually tastes good,” says Orozco, a humanities and engineering major. A year later, in 3.000, he expanded his understanding of making a good brew, particularly through the group project with Jutamulia and other students to fix bad coffee.The group prepared a control sample of “perfectly brewed” coffee — based on taste, coffee-to-water ratio, and other standards covered in class — alongside coffee that was under-extracted and over-extracted. Under-extracted coffee, made with water that isn’t hot enough or brewed for too short a time, tastes sharp or sour. Over-extracted coffee, brewed with too much coffee or for too long, tastes bitter.Those coffee samples got additives and were analyzed using Fourier Transform Infrared (FTIR) spectroscopy, measuring how coffee absorbed infrared light to identify flavor-related compounds. Jutamulia examined FTIR readings taken from a sample with lime juice to see how the citric acid influenced its chemical profile.“Can we find any correlation between what we saw and the existing known measurements of citric acid?” asks Jutamulia, who studied computation and cognition at MIT, graduating last May.Another group dove into coffee storage, questioning why conventional wisdom advises against freezing.“We just wondered why that’s the case,” says electrical engineering and computer science major Noah Wiley, a coffee enthusiast with his own espresso machine.The team compared methods like freezing brewed coffee, frozen coffee grounds, and whole beans ground after freezing, evaluating their impact on flavor and chemical composition.“Then we’re going to see which ones taste good,” says Wiley. The team used a class coffee review sheet to record attributes like acidity, bitterness, sweetness, and overall flavor, pairing the results with FTIR analysis to determine how storage affected taste.Wiley acknowledged that “good” is subjective. “Sometimes there’s a group consensus. I think people like fuller coffee, not watery,” he says.Other student projects compared caffeine levels in different coffee types, analyzed the effect of microwaving coffee on its chemical composition and flavor, and investigated the differences between authentic and counterfeit coffee beans.“We gave the students some papers to look at in case they were interested,” says Justin Lavallee, Breakerspace manager and co-teacher of the class. “But mostly we told them to focus on something they wanted to learn more about.”Drip, drip, dripBeyond answering specific questions about coffee, both students and teachers gained deeper insights into the beverage.“Coffee is a complicated material. There are thousands of molecules in the beans, which change as you roast and extract them,” says Grossman. “The number of ways you can engineer this collection of molecules — it’s profound, ranging from where and how the coffee’s grown to how the cherries are then treated to get the beans to how the beans are roasted and ground to the brewing method you use.”Dinesen learned firsthand, discovering, for example, that darker roasts have less caffeine than lighter roasts, puncturing a common misconception. “You can vary coffee so much — just with the roast of the bean, the size of the ground,” she says. “It’s so easily manipulatable, if that’s a word.”In addition to learning about the science and chemistry behind coffee, Dinesen and McDonald gained new brewing techniques, like using a pour-over cone. The pair even incorporated coffee making and testing into their study routine, brewing coffee while tackling problem sets for another class.“I would put my pour-over cone in my backpack with a Ziploc bag full of grounds, and we would go to the Student Center and pull out the cone, a filter, and the coffee grounds,” McDonald says. “And then we would make pour-overs while doing a P-set. We tested different amounts of water, too. It was fun.”Tony Chen, a materials science and engineering major, reflected on the 3.000’s title — “Using the Breakerspace to Make the Perfect Cup” — and whether making a perfect cup is possible. “I don’t think there’s one perfect cup because each person has their own preferences. I don’t think I’ve gotten to mine yet,” he says.Enthusiasm for coffee’s complexity and the discovery process was exactly what Grossman hoped to inspire in his students. “The best part for me was also just seeing them developing their own sense of curiosity,” he says.He recalled a moment early in the class when students, after being given a demo of the optical microscope, saw the surface texture of a magnified coffee bean, the mottled shades of color, and the honeycomb-like pattern of tiny irregular cells.“They’re like, ‘Wait a second. What if we add hot water to the grounds while it’s under the microscope? Would we see the extraction?’ So, they got hot water and some ground coffee beans, and lo and behold, it looked different. They could see the extraction right there,” Grossman says. “It’s like they have an idea that’s inspired by the learning, and they go and try it. I saw that happen many, many times throughout the semester.” More

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      in Energy

      Celebrating five years of MIT.nano

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      There is vast opportunity for nanoscale innovation to transform the world in positive ways — expressed MIT.nano Director Vladimir Bulović as he posed two questions to attendees at the start of the inaugural Nano Summit: “Where are we heading? And what is the next big thing we can develop?”

      “The answer to that puts into perspective our main purpose — and that is to change the world,” Bulović, the Fariborz Maseeh Professor of Emerging Technologies, told an audience of more than 325 in-person and 150 virtual participants gathered for an exploration of nano-related research at MIT and a celebration of MIT.nano’s fifth anniversary.

      Over a decade ago, MIT embarked on a massive project for the ultra-small — building an advanced facility to support research at the nanoscale. Construction of MIT.nano in the heart of MIT’s campus, a process compared to assembling a ship in a bottle, began in 2015, and the facility launched in October 2018.

      Fast forward five years: MIT.nano now contains nearly 170 tools and instruments serving more than 1,200 trained researchers. These individuals come from over 300 principal investigator labs, representing more than 50 MIT departments, labs, and centers. The facility also serves external users from industry, other academic institutions, and over 130 startup and multinational companies.

      A cross section of these faculty and researchers joined industry partners and MIT community members to kick off the first Nano Summit, which is expected to become an annual flagship event for MIT.nano and its industry consortium. Held on Oct. 24, the inaugural conference was co-hosted by the MIT Industrial Liaison Program.

      Six topical sessions highlighted recent developments in quantum science and engineering, materials, advanced electronics, energy, biology, and immersive data technology. The Nano Summit also featured startup ventures and an art exhibition.

      Watch the videos here.

      Seeing and manipulating at the nanoscale — and beyond

      “We need to develop new ways of building the next generation of materials,” said Frances Ross, the TDK Professor in Materials Science and Engineering (DMSE). “We need to use electron microscopy to help us understand not only what the structure is after it’s built, but how it came to be. I think the next few years in this piece of the nano realm are going to be really amazing.”

      Speakers in the session “The Next Materials Revolution,” chaired by MIT.nano co-director for Characterization.nano and associate professor in DMSE James LeBeau, highlighted areas in which cutting-edge microscopy provides insights into the behavior of functional materials at the nanoscale, from anti-ferroelectrics to thin-film photovoltaics and 2D materials. They shared images and videos collected using the instruments in MIT.nano’s characterization suites, which were specifically designed and constructed to minimize mechanical-vibrational and electro-magnetic interference.

      Later, in the “Biology and Human Health” session chaired by Boris Magasanik Professor of Biology Thomas Schwartz, biologists echoed the materials scientists, stressing the importance of the ultra-quiet, low-vibration environment in Characterization.nano to obtain high-resolution images of biological structures.

      “Why is MIT.nano important for us?” asked Schwartz. “An important element of biology is to understand the structure of biology macromolecules. We want to get to an atomic resolution of these structures. CryoEM (cryo-electron microscopy) is an excellent method for this. In order to enable the resolution revolution, we had to get these instruments to MIT. For that, MIT.nano was fantastic.”

      Seychelle Vos, the Robert A. Swanson (1969) Career Development Professor of Life Sciences, shared CryoEM images from her lab’s work, followed by biology Associate Professor Joey Davis who spoke about image processing. When asked about the next stage for CryoEM, Davis said he’s most excited about in-situ tomography, noting that there are new instruments being designed that will improve the current labor-intensive process.

      To chart the future of energy, chemistry associate professor Yogi Surendranath is also using MIT.nano to see what is happening at the nanoscale in his research to use renewable electricity to change carbon dioxide into fuel.

      “MIT.nano has played an immense role, not only in facilitating our ability to make nanostructures, but also to understand nanostructures through advanced imaging capabilities,” said Surendranath. “I see a lot of the future of MIT.nano around the question of how nanostructures evolve and change under the conditions that are relevant to their function. The tools at MIT.nano can help us sort that out.”

      Tech transfer and quantum computing

      The “Advanced Electronics” session chaired by Jesús del Alamo, the Donner Professor of Science in the Department of Electrical Engineering and Computer Science (EECS), brought together industry partners and MIT faculty for a panel discussion on the future of semiconductors and microelectronics. “Excellence in innovation is not enough, we also need to be excellent in transferring these to the marketplace,” said del Alamo. On this point, panelists spoke about strengthening the industry-university connection, as well as the importance of collaborative research environments and of access to advanced facilities, such as MIT.nano, for these environments to thrive.

      The session came on the heels of a startup exhibit in which eleven START.nano companies presented their technologies in health, energy, climate, and virtual reality, among other topics. START.nano, MIT.nano’s hard-tech accelerator, provides participants use of MIT.nano’s facilities at a discounted rate and access to MIT’s startup ecosystem. The program aims to ease hard-tech startups’ transition from the lab to the marketplace, surviving common “valleys of death” as they move from idea to prototype to scaling up.

      When asked about the state of quantum computing in the “Quantum Science and Engineering” session, physics professor Aram Harrow related his response to these startup challenges. “There are quite a few valleys to cross — there are the technical valleys, and then also the commercial valleys.” He spoke about scaling superconducting qubits and qubits made of suspended trapped ions, and the need for more scalable architectures, which we have the ingredients for, he said, but putting everything together is quite challenging.

      Throughout the session, William Oliver, professor of physics and the Henry Ellis Warren (1894) Professor of Electrical Engineering and Computer Science, asked the panelists how MIT.nano can address challenges in assembly and scalability in quantum science.

      “To harness the power of students to innovate, you really need to allow them to get their hands dirty, try new things, try all their crazy ideas, before this goes into a foundry-level process,” responded Kevin O’Brien, associate professor in EECS. “That’s what my group has been working on at MIT.nano, building these superconducting quantum processors using the state-of-the art fabrication techniques in MIT.nano.”

      Connecting the digital to the physical

      In his reflections on the semiconductor industry, Douglas Carlson, senior vice president for technology at MACOM, stressed connecting the digital world to real-world application. Later, in the “Immersive Data Technology” session, MIT.nano associate director Brian Anthony explained how, at the MIT.nano Immersion Lab, researchers are doing just that.

      “We think about and facilitate work that has the human immersed between hardware, data, and experience,” said Anthony, principal research scientist in mechanical engineering. He spoke about using the capabilities of the Immersion Lab to apply immersive technologies to different areas — health, sports, performance, manufacturing, and education, among others. Speakers in this session gave specific examples in hardware, pediatric health, and opera.

      Anthony connected this third pillar of MIT.nano to the fab and characterization facilities, highlighting how the Immersion Lab supports work conducted in other parts of the building. The Immersion Lab’s strength, he said, is taking novel work being developed inside MIT.nano and bringing it up to the human scale to think about applications and uses.

      Artworks that are scientifically inspired

      The Nano Summit closed with a reception at MIT.nano where guests could explore the facility and gaze through the cleanroom windows, where users were actively conducting research. Attendees were encouraged to visit an exhibition on MIT.nano’s first- and second-floor galleries featuring work by students from the MIT Program in Art, Culture, and Technology (ACT) who were invited to utilize MIT.nano’s tool sets and environments as inspiration for art.

      In his closing remarks, Bulović reflected on the community of people who keep MIT.nano running and who are using the tools to advance their research. “Today we are celebrating the facility and all the work that has been done over the last five years to bring it to where it is today. It is there to function not just as a space, but as an essential part of MIT’s mission in research, innovation, and education. I hope that all of us here today take away a deep appreciation and admiration for those who are leading the journey into the nano age.” More

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      in Environment

      Exploring the nanoworld of biogenic gems

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      A new research collaboration with The Bahrain Institute for Pearls and Gemstones (DANAT) will seek to develop advanced characterization tools for the analysis of the properties of pearls and to explore technologies to assign unique identifiers to individual pearls.

      The three-year project will be led by Admir Mašić, associate professor of civil and environmental engineering, in collaboration with Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology and professor of electrical engineering and computer science.

      “Pearls are extremely complex and fascinating hierarchically ordered biological materials that are formed by a wide range of different species,” says Mašić. “Working with DANAT provides us a unique opportunity to apply our lab’s multi-scale materials characterization tools to identify potentially species-specific pearl fingerprints, while simultaneously addressing scientific research questions regarding the underlying biomineralization processes that could inform advances in sustainable building materials.”

      DANAT is a gemological laboratory specializing in the testing and study of natural pearls as a reflection of Bahrain’s pearling history and desire to protect and advance Bahrain’s pearling heritage. DANAT’s gemologists support clients and students through pearl, gemstone, and diamond identification services, as well as educational courses.

      Like many other precious gemstones, pearls have been human-made through scientific experimentation, says Noora Jamsheer, chief executive officer at DANAT. Over a century ago, cultured pearls entered markets as a competitive product to natural pearls, similar in appearance but different in value.

      “Gemological labs have been innovating scientific testing methods to differentiate between natural pearls and all other pearls that exist because of direct or indirect human intervention. Today the world knows natural pearls and cultured pearls. However, there are also pearls that fall in between these two categories,” says Jamsheer. “DANAT has the responsibility, as the leading gemological laboratory for pearl testing, to take the initiative necessary to ensure that testing methods keep pace with advances in the science of pearl cultivation.”

      Titled “Exploring the Nanoworld of Biogenic Gems,” the project will aim to improve the process of testing and identifying pearls by identifying morphological, micro-structural, optical, and chemical features sufficient to distinguish a pearl’s area of origin, method of growth, or both. MIT.nano, MIT’s open-access center for nanoscience and nanoengineering will be the organizational home for the project, where Mašić and his team will utilize the facility’s state-of-the-art characterization tools.

      In addition to discovering new methodologies for establishing a pearl’s origin, the project aims to utilize machine learning to automate pearl classification. Furthermore, researchers will investigate techniques to create a unique identifier associated with an individual pearl.

      The initial sponsored research project is expected to last three years, with potential for continued collaboration based on key findings or building upon the project’s success to open new avenues for research into the structure, properties, and growth of pearls. More