Materials Day 2017
Bringing together researchers from different science and engineering fields promises solutions to global needs in energy, health and quality of life.
Interdisciplinary materials research holds the key to solving the existential challenges facing humanity, former Sandia National Laboratories executive Julia M. Phillips told the annual MIT Materials Research Laboratory [MRL] Materials Day Symposium on Wednesday, Oct. 11, 2017. “What is both very exciting for us as materials researchers, also a little frustrating, is that the real impact of materials occurs when they turn into something that you actually carry around in your pocket or whatever,” Phillips said.
During the second half of the 20th century, many of the technological advances that we take for granted today, such as laptop computers and smart phones, came from fundamental advances in materials research and the ability to control and make materials, she noted. Phillips, who retired from Sandia National Laboratories as Vice President and Chief Technology Officer, also serves as chair of the MRL External Advisory Board and is a member of the National Science Board.
MRL formed from the merger of the Materials Processing Center and the Center for Materials Science and Engineering, effective Oct. 1, 2017. MRL Director Carl V. Thompson noted in his introductory remarks, the appointment of Associate Professor of Materials Science and Engineering Geoffrey S.D. Beach as co-director of the MRL and principal investigator for the National Science Foundation Materials Research Science and Engineering Center.
- Frontier for metals at high temperature Frontier for metals at high temperature
- MIT Materials Research Lab Director MIT Materials Research Lab Director
- Merging 2D materials with CMOS Merging 2D materials with CMOS
- Safer lithium batteries Safer lithium batteries
- 3D printing a new manufacturing model 3D printing a new manufacturing model
- Interdisciplinary model key to progress Interdisciplinary model key to progress
- New tools for brain exploration New tools for brain exploration
- Phase change materials Phase change materials
Fueled by industrial needs and government-funded research in the post-World War II era, “Materials research was undeniably an early model for interdisciplinary research,” Phillips said. With new tools such as scanning probe microscopes to understand the structure and properties of materials, materials scientists in the last half of the 20th Century created whole new classes of materials and products, ranging from super alloys that enabled larger and more reliable jet engines to strained layer superlattices that underlie modern magnetic recording,7 lasers and infrared detectors.
Future gains will come from the ability to synthesize and control increasingly complex materials, Phillips says, noting progress in areas such as high-temperature superconductors, porous solids like metal organic frameworks, and metamaterials that generate new properties from combining biological materials, organics, ceramics and metals at near molecular scale precision in ways not found in nature. “Somewhere in the fuzzy space between molecules and materials,” Phillips notes, these newer materials have very interesting properties that are still in the process of being fully explored, and they will be exploited in the years to come. “It’s very clear to many people that these also will be transformational as we move forward,” she says.
The materials research approach, which brings together researchers from across different science and engineering fields to solve complex problems, provides a model for solving 21st Century challenges in energy, environment and sustainability; health care and medicine; vulnerability to human and natural threats; and expanding and enhancing human capability and joy. “These are exemplars, but you can see materials written all over this list, and I would posit that any comparable list you might come up with would have materials written all over it,” Phillips said. “In order to address those grand challenges, we really need to be able to treat realistically complex systems that bring together all of these disciplines from the sciences, from engineering, from the social and behavioral sciences, and arguably even from the arts.”
Progress in scientific understanding and computational modeling are accelerating researchers’ ability to predict the structure and properties of new materials before actually making them, Phillips said.
MIT faculty members Antoine Allanore, Polina Anikeeva, A. John Hart, Pablo Jarillo-Herrero, Juejun Hu, and Jennifer Rupp presented research updates on their recent work which spans a range from ultra-thin layered materials for new electronic devices and cellular level probes for the brain and spinal cord to larger scale methods for 3D printing and metals processing.
Merging 2D materials with CMOS
Associate Professor of Physics Pablo Jarillo-Herrero stacks atomically thin, two-dimensional [2D] layers of different materials to discover new properties. Jarillo-Herrero’s lab demonstrated photodetectors, solar cells and the world’s thinnest LED. With materials such as tungsten selenide [WSe2], changing the number of layers also changes their electronic properties. Although graphene itself has no bandgap, closely aligning the lattices of graphene and boron nitride opens a 30-millivolt bandgap in graphene, he said.
“You have full electronic control with gate voltages,” Jarillo-Herrero said. Using bilayer molybdenum ditelluride, which is 10,000 times thinner than a silicon solar cell, he showed in work published in Nature Nanotechnology, a photodetector just 10 nanometers thick can be integrated on a silicon photonic crystal waveguide.
“You can just stack this at the very end of your CMOS [complementary metal oxide semiconductor] processing, and you don’t have to do any extra fabrication, any extra growth, you can just slap it on top,” Jarillo-Herrero explained. “It can be made as thin as 4 nanometers, so it’s still ultra thin, and you have a high degree of control in an ultra thin platform. The whole thing is semitransparent so we can see the light go in and out.” These new devices can be operated at telecommunications wavelengths by tuning the bandgap of the material.
Phase change materials
Juejun (JJ) Hu, the Merton C. Flemings Associate Professor of Materials Science and Engineering, is reducing power consumption, shrinking device size and ramping up processing speed with innovative combinations of materials that alternate between two different solid states, or phases, such as an alloy of germanium, antimony, selenium and tellurium. These materials are the basis for nonvolatile storage, meaning their memory state is preserved even when the power is turned off. Hu collaborated with MIT Professor Jeffrey C. Grossman and former postdoc Huashan Li to identify desirable materials for these alloys from first principles calculations, and graduate materials science and engineering student Yifei Zhang did much of the experimental work.
An earlier generation of devices based on germanium, antimony and tellurium [GST] suffers from losses to light absorption by the material. To overcome this problem, Hu substituted some of the tellurium with a lighter element, selenium, creating a new four-element structure of germanium, antimony, selenium and tellurium [GSST]. “We increase the bandgap to suppress short wavelength absorption, and we actually minimize any carrier mobility to mitigate the free carrier absorption,” he explained. Switching between amorphous and crystalline states can be triggered with a laser pulse or an electrical signal.
Although the structural state switching happens on the order of 100 nanoseconds, figuring out the techniques to accomplish it took a year of work, Hu said. Specifically, he found that using materials that switch between amorphous and crystalline states allows light to be directed over two different paths and reduces power consumption. He coupled this GSST optical phase change material with silicon nitride microresonators and waveguides to show this behavior. These switches based on phase change materials can be connected in a matrix to enable variable light control on a chip. Ultimately, Hu hopes to use this technology to build re-programmable photonic integrated circuits.
New tools for brain exploration
Class of 1942 Associate Professor in Materials Science and Engineering Polina Anikeeva works at the border between synthetic devices and the nervous system. Traditional electronic devices, with hardness like a knife, can trigger a foreign-body response from brain tissue, which typically is as soft as pudding or yogurt. Working with Prof. Yoel Fink and other MIT colleagues, Anikeeva developed soft polymer-based devices to stimulate and record activity of brain and spinal cord tissue borrowing from optical fiber drawing techniques.
An early version of their multi-functional fibers included three key elements: conductive polyethylene carbon composite electrodes to record brain cell activity; a transparent polycarbonate waveguide with cyclic olefin copolymer cladding to deliver light; and microfluidic channels to deliver drugs.
“Using this structure, for the first time, we were able to record, stimulate and pharmacologically modulate neural activity,” Anikeeva said. But the device recorded activity from clusters of neurons, not individual neurons. Anikeeva and her team addressed this problem by integrating graphite into the polyethylene composite electrodes, which increased their conductivity enough to shrink them into a structure that is as thin as a human hair. The device has six electrodes, an optical waveguide and two microfluidic channels.
Yet adding graphite increased the size and hardness of the glassy polycarbonate device, so her group turned to a new process using rubbery, stretchy polymers that they then coated with a conductive metal nanowire mesh. “This mesh of conductive metal nanowires can maintain low impedance even at 100 percent strain, and it maintains its structural integrity without any changes up to 20 percent strain, which is sufficient for us to operate in the spinal cord,” Anikeeva said.
Her students implanted these nanowire-mesh coated fibers in mice, which allowed them to stimulate and record neural activity in the spinal cord. A video showed a mouse moving its hindlimb when an optical signal delivered to the lumbar spinal cord traveled down the sciatic nerve to the gastrocnemius muscle. In these experiments, the device implanted in mice showed no decline in performance a year after surgery, Anikeeva said.
More recently, Anikeeva developed iron oxide-based nanoparticles that heat up in an applied magnetic field, which can trigger a response from neurons in the brain that express ion channels that are sensitive to heat such as capsaicin receptor, the same mechanism that is triggered when we eat hot peppers. Experimenting with mice, Anikeeva injected these tiny particles deep in the brain in a section that is associated with reward. “In our lab, we have started by modeling hysteresis in magnetic nanoparticles, synthesizing a broad range of these nanomaterials by engineering iron oxide with dopants and looking at different sizes and shapes, developing power electronics and a biological tool kit to assess this process,” Anikeeva explained. “In this case, there is no external hardwire, no wires, no implants, nothing is sticking out of the brain… however, they can now perceive magnetic field.” she said. To quantify their results, the researchers measured calcium ion influx into neurons. Work is now focused on shortening the response time to a few thousandths of a second by improving the heat output of the magnetic nanoparticles.
Ceramics for Solid-State Batteries, CO2 Sensors and Memristive Computing
Jennifer L. M. Rupp, the Thomas Lord Assistant Professor of Materials Science and Engineering, presented research showing a solid lithium garnet electrolyte can lead to batteries miniaturized on an integrated circuit chip.
Safety concerns regarding lithium batteries stem from their liquid component, which serves as the electrolyte and presents a risk of catching fire in air. Replacing the liquid electrolyte with a solid one could make batteries safer, Rupp explained. Her research shows that a ceramic material made of garnet, a material that is perhaps more familiar as a gemstone, can effectively pass lithium through a battery cell, but because it is solid, can be very safe for batteries and also have the opportunity to be miniaturized to thin film architectures. This garnet is a four-element compound of lithium, lanthanum, zirconium and oxygen. “The lithium is completely encapsulated; there is no risk of inflammation,” Rupp said.
In published research, Rupp showed that pairing a lithium titanium oxide anode with a ceramic garnet electrolyte and blurring the interface between the two materials allowed much faster battery charging time for large-scale cells. Lessons learned from applying these garnet materials pointed also to a new use for carbon dioxide sensing. “We can reconfigure the electrodes to have one electrode which simply goes as a reference, and another which undergoes a chemical reaction with carbon dioxide, and we use a tracker potential to track the effective change of carbon dioxide concentration in the environment based on bulk processing,” she explained. Rupp is also developing strained multi-layer materials to improve storage for memristive memory and computing elements.
Frontier for metals at high temperature
Associate Professor of Metallurgy Antoine Allanore pointed out that from 1980 to 2010, the world almost doubled its consumption of materials, with the fastest growth in metals and minerals. Such demand is due to the formidable low cost and high productivity of materials processing. The majority of such processes involve at some stage a high temperature operation and often the molten state of matter. Developing the science and engineering of the molten state brings huge opportunities, for example heat management in high-temperature processes such as metals extraction and glass making.
Steelmaking, for example, is already a highly efficient manufacturing process, turning out rebar, coil or wires of steel at a cost less than 32 cents per kilogram [about 15 cents per pound]. “Productivity is actually the key criteria to make materials processing successful and matter at the scale of the challenge of adding 2 billion people in the next 20 years,” he said.
Allanore’s group demonstrated that tin sulfide at high temperature, about 1,130 degrees Celsius [2,066 Fahrenheit], is an effective thermoelectric generator. “We have indications that the theoretical figure of merit for some sulfides, can be up to 1 at 1,130 [degrees Celsius]. For molten copper sulfide for example, we have estimates of the thermal conductivity, the melting point, and we have a cost that is a little bit high in my opinion, but that’s the nature of the research,” Allanore said. When his group looked at existing data, they found that for many molten compounds of sulfur and a metal, such as tin, lead or nickel, the thermoelectric figure of merit, as well as the compositional phases, had never been quantified, opening a frontier for new materials science research at high temperature. “It’s actually very difficult to know what are the true properties of the liquid,” Allanore said. “I need to know if that material will have semiconductivity. I need to know if it’s going to be denser or lighter than another liquid. … We don’t actually have computational methods to predict such property for liquids at high temperature.”
To address the problem, Allanore studied the relation in high-temperature melts between transport properties, including electrical conductivity and Seebeck coefficients, and a thermodynamic property called entropy. “We’ve put together a theoretical model that connects the transport property, like thermal power, and the thermodynamic property like entropy. This is important because it works for semiconductors, it works for metallic materials and more importantly it allows to find out regions of immiscibility in liquids,” Allanore said. Immiscibility means a material in the given condition will separate into two phases that do not mix together and remain separate.
Allanore has also developed a new method for observing molten compounds such as alumina, using a floating zone furnace, which is a transparent quartz tube located at the focal distance of four lamps. “If we can do that with oxides, we would really like to do that with sulfides,” he explained, showing a picture of molten tin sulfide sitting on a graphite plate in the floating zone furnace. The wide range of temperatures and properties of molten materials, “the ultimate state of condensed matter”, allows for better heat management, higher processing temperatures and electricity harvesting or electrical control of heat flow, he said.
3D printing a new manufacturing model
Traditional manufacturing requires economies of scale, in particular, large production volumes because of the fixed costs necessary to set up the production process, but 3D printing and other additive manufacturing technologies offer an alternative of high-performance, customizable products and devices, Associate Professor of Mechanical Engineering A. John Hart said.
Additive manufacturing is already a $6 billion a year business with reach from Hollywood special effects to high-tech jet engine nozzles. “Additive manufacturing already enables a diverse collection of materials, applications, and related processes – including by extrusion of plastics, melting metals, using lasers, and by coordinated chemical reactions that essentially are done with point wise control,” Hart explained.
“We can think of accessing new spaces in terms of the value of the products we create using additive manufacturing, also generally known as 3D printing. 3D printing is reshaping the axes by which we judge the economic viability of a manufacturing process, and allowing us to access new value spaces. For instance, we can think not only about production volume, but think about advantages in complexity of geometries, and advantages by customization of products to specific markets or even individuals. In these ways, 3D printing is influencing the entire product life cycle,” Hart said.
For instance, Hart’s group studied existing 3D printers to discover how to speed up the process from about 60 minutes to just 5 to 10 minutes to print a handheld mechanical part such as a gear. Former graduate student Jamison Go [SM, 2015] led this work, Hart said, building a desktop 3D printer about the size of a small microwave oven. The system features a control system for the printhead that moves the motors to the corner; an extrusion mechanism that drives the feedstock polymer filament like a screw; and a laser that penetrates and melts the polymer.
“By combining the fast motion control, the high heat transfer, and the high force, we can overcome the limits of the existing system,” Hart explained. The new design is three to 10 times faster in build rate than existing machines. “These kinds of steps forward can also change how we think about producing objects. If you can make something fast, you can think about how you might, or how others might, work differently,” he said. He mentioned, for instance, physicians who may need to 3D print a part for an emergency medical operation, or a repair technician who could use a 3D printer rather than hold inventory of many spare parts.
Hart’s group is currently working in collaboration with Oak Ridge National Lab on algorithms for optimization of 3D printing toolpaths, and adapting his innovations to large-scale 3d printers. “We can think about upscaling these principles to high productivity systems that are not only printing small things but printing big things,” Hart said. Hart has also worked with 3D printing of cellulose, which can be used for customization of consumer products and antimicrobial devices, and is the world’s most abundant natural polymer. He co-founded the company Desktop Metal with three other MIT faculty members and Ric Fulop SL ’06, who serves as Desktop Metal’s CEO. “The company is only two years old and will soon ship its first product which enables an entirely new approach to metal 3D printing,” Hart said.
– Denis Paiste, MIT Materials Research Laboratory
October 30, 2017
Coming up in November Newsletter: Materials Day Panel Discussion and Poster Session coverage
Undergraduates from U.S. and Puerto Rico seek life-enriching experiences through MIT Materials Research Laboratory science and engineering internships.
Coming to MIT has been a dream since a very young age, says University of Puerto Rico at Mayaguez mechanical engineering major Fernando Nieves Munoz. This summer, he’ll get to fulfill that ambition as one of 12 top-ranked undergraduate Summer Scholars selected by the MIT Materials Research Laboratory to conduct graduate-level research.
“As an engineering student, I expect to grow and be deeply immersed as an educator and researcher in the future,” Nieves says. He hopes to join a project to develop and enhance properties of new materials by analyzing their behaviors and structures.
Exploring renewable energy
Interest in different aspects of renewable energy is the most popular research theme among this year’s student interns. “I would like to apply my knowledge of electrochemistry to an area of research I have not previously explored, such as battery materials,” says Elizabeth [Lily] Hallett, a chemical engineering major at the University of Arkansas, Fayetteville. “My ultimate goal is to improve energy storage and conversion devices that will help our society transition to renewable energy.”
Sarai Patterson, a University of Utah materials science and engineering major, is interested in both renewable energy and environmental remediation. “Some examples of this might be nanostructured materials for energy applications, photovoltaic devices, sustainable polymers, carbon sequestration, microbial fuel cells, or thermoelectric materials,” Patterson explains. “I am excited to directly be a part of the research at MIT, to be mentored by a faculty member and gain the experience of working full-time on a project.”
Oregon State University physics major Ryan Tollefsen would like to conduct research on materials for organic solar cells or fusion reactor blankets. “By the end of this program, I expect to be more fluent in the language of experimental physics, strengthen my computational skills, and develop meaningful friendships,” Tollefsen says.
Working in solar technologies is a career goal for University of Rhode Island chemical engineering major Michael Molinski. “I am looking forward to working with the many accomplished professors and students at MIT, all of whom share a common passion for their research and the betterment of society,” Molinski says.
Julianna La Lane, a University of Puerto Rico at Mayaguez mechanical engineering student, is inspired by Assistant Professor Jennifer L. M. Rupp’s research on ceramic materials to convert solar energy into renewable fuel. “I hope this research will help me build a clearer path towards graduate school and further down the road in the design and construction of products that will promote the use of renewable energy and prevent the further warming of planet Earth,” La Lane says.
Brown University materials engineering major Ekaterina Tsotsos says, “My main goal is to pursue research aimed towards making sustainable energy more affordable and accessible,” but she cautions, “I'm not going to pretend I know exactly what I want to study; all of the projects look exciting in their own ways!”
Bio-inspired materials and designs are also popular with incoming Summer Scholars. “I hope to pursue areas of research intrinsically connected to sustainability and the environment. Specifically, I am interested in bio-inspired design and biomimicry,” says Danielle Beatty, a sophomore materials science and engineering major at the University of Utah.
Abigail Nason seeks to study bio-inspired materials because they have the functionality of traditional polymer materials while also benefiting the health of the environment. “As a current undergraduate student, I balance my research time with a full schedule of classes, but this summer I will be excited to spend a majority of my time focused on my research project,” says Nason, a University of Florida junior who is majoring in materials science and engineering. “While at MIT, I hope to learn more about what is involved in the design and development of biologically inspired materials. Materials that are biodegradable such as these are becoming increasingly important as the earth collects more and more synthetic plastics in its landfills and oceans.”
Drawn to biomaterials and medical materials, junior Simon Egner wants to attend graduate school because he cannot imagine doing anything other than research as a career. “This internship is an unmatched opportunity to gain experience in academic research,” the University of Illinois at Urbana-Champaign materials science and engineering major says.
Johns Hopkins University junior Sabrina Shen hopes to pursue translational research in soft materials for tissue engineering, immunoengineering, or other biomedical applications. “This allows me to draw from my academic background in biomaterials and to contribute to truly impacting lives,” Shen says.
“I'm most looking forward to exploring Boston and the neighborhoods surrounding MIT,” materials science and engineering major Shen says. “I love that I get to conduct fascinating and impactful research in one of the world's top institutions while experiencing a city with such rich culture and history.
Oregon State University junior Alvin Chang is interested in learning the commercialization process of engineering innovation and technology with particular application to sustainable energy and photonic nanostructures. “I am still at an impasse when it comes to committing to a direction for my future research, but I am sure that I want my research to make a humanitarian impact on others,” says Chang, a double major in chemical engineering and biological engineering, with a minor in entrepreneurship.
Summer Scholars serve as interns on the MIT campus in Cambridge, Mass., through the MIT MRL’s Materials Research Science and Engineering Center, with support from the National Science Foundation’s Research Experience for Undergraduates (REU) program, the AIM Photonics Academy and the MRL Collegium.
Begun in 1983, the program has brought hundreds of the best science and engineering undergraduates in the country to MIT for graduate-level materials research. This year’s program runs from June 17 to August 11, 2018.
|Angela Belcher, chair of MIT’s Department of Biological Engineering, and Neel Bardhan, postdoctoral fellow in MIT's Koch Institute, with an oversized model of carbon nanotube probes for detecting tiny ovarian tumors. Image, Koch Institute/MIT.|
An MIT Koch Institute team, led by Angela Belcher, chair of MIT’s Department of Biological Engineering, won the 2020 STAT Madness competition with technology to see tiny ovarian tumors.
Read more on STAT News.
New material reversibly changes its structure in response to different wavelengths of light.
|MIT chemists have designed a polymer that can reversibly switch from a large structure (orange spheres) to the smaller blue shapes, in response to light. Image, Demin Liu/Molgraphics|
MIT researchers have designed a polymer material that can change its structure in response to light, converting from a rigid substance to a softer one that can heal itself when damaged.
“You can switch the material states back and forth, and in each of those states, the material acts as though it were a completely different material, even though it’s made of all the same components,” says Jeremiah Johnson, an associate professor of chemistry at MIT, a member of MIT’s Koch Institute for Integrative Cancer Research and the Program in Polymers and Soft Matter, and the leader of the research team.
The material consists of polymers attached to a light-sensitive molecule that can be used to alter the bonds formed within the material. Such materials could be used to coat objects such as cars or satellites, giving them the ability to heal after being damaged, though such applications are still far in the future, Johnson says.
The lead author of the paper, which appears in the July 18 issue of Nature, is MIT graduate student Yuwei Gu. Other authors are MIT graduate student Eric Alt, MIT assistant professor of chemistry Adam Willard, and Heng Wang and Xiaopeng Li of the University of South Florida.
Many of the properties of polymers, such as their stiffness and their ability to expand, are controlled by their topology — how the components of the material are arranged. Usually, once a material is formed, its topology cannot be changed reversibly. For example, a rubber ball remains elastic and cannot be made brittle without changing its chemical composition.
In this paper, the researchers wanted to create a material that could reversibly switch between two different topological states, which has not been done before.
Johnson and his colleagues realized that a type of material they designed a few years ago, known as polymer metal-organic cages, or polyMOCs, was a promising candidate for this approach. PolyMOCs consist of metal-containing, cage-like structures joined together by flexible polymer linkers. The researchers created these materials by mixing polymers attached to groups called ligands, which can bind to a metal atom.
Each metal atom — in this case, palladium — can form bonds with four ligand molecules, creating rigid cage-like clusters with varying ratios of palladium to ligand molecules. Those ratios determine the size of the cages.
In the new study, the researchers set out to design a material that could reversibly switch between two different-sized cages: one with 24 atoms of palladium and 48 ligands, and one with three palladium atoms and six ligand molecules.
To achieve that, they incorporated a light-sensitive molecule called DTE into the ligand. The size of the cages is determined by the angle of bonds that a nitrogen molecule on the ligand forms with palladium. When DTE is exposed to ultraviolet light, it forms a ring in the ligand, which increases the size of the angle at which nitrogen can bond to palladium. This makes the clusters break apart and form larger clusters.
When the researchers shine green light on the material, the ring is broken, the bond angle becomes smaller, and the smaller clusters re-form. The process takes about five hours to complete, and the researchers found they could perform the reversal up to seven times; with each reversal, a small percentage of the polymers fails to switch back, which eventually causes the material to fall apart.
|The instrument, a rheometer, can measure mechanical properties of materials. The blue-colored gel on the stage of the instrument is the materials. The rheometer is used to measure the modulus of the material, thus gaining an understanding of its stiffness and degree of dynamics. Image, Felice Frankel|
When the material is in the small-cluster state, it becomes up to 10 times softer and more dynamic. “They can flow when heated up, which means you could cut them and upon mild heating that damage will heal,” Johnson says.
This approach overcomes the tradeoff that usually occurs with self-healing materials, which is that structurally they tend to be relatively weak. In this case, the material can switch between the softer, self-healing state and a more rigid state.
“Reversibly switching topology of polymer networks has never been reported before and represents a significant advancement in the field,” says Sergei Sheiko, a professor of chemistry at the University of North Carolina, who was not involved in the research. “Without changing network composition, photoswitchable ligands enable remotely activated transition between two topological states possessing distinct static and dynamic properties.”
In this paper, the researchers used the polymer polyethylene glycol (PEG) to make their material, but they say this approach could be used with any kind of polymer. Potential applications include self-healing materials, although for this approach to be widely used, palladium, a rare and expensive metal, would likely have to be replaced by a cheaper alternative.
“Anything made from plastic or rubber, if it could be healed when it was damaged, then it wouldn’t have to be thrown away. Maybe this approach would provide materials with longer life cycles,” Johnson says.
Another possible application for these materials is drug delivery. Johnson believes it could be possible to encapsulate drugs inside the larger cages, then expose them to green light to make them open up and release their contents. Applying green light could enable recapture of the drugs, providing a novel approach to reversible drug delivery.
The researchers are also working on creating materials that can reversibly switch from a solid state to a liquid state, and on using light to create patterns of soft and rigid sections within the same material.
The research was funded by the National Science Foundation.
– Anne Trafton | MIT News Office
July 18, 2018
J-WAFS-funded MIT research team shows a new method of fertilizer production can better suit the needs of farms in Africa and around the globe.
|For tropical growing regions in Brazil and some countries in Africa, differing soil and rock compositions make for a poor match for the fertilizers that are currently on the market. J-WAFS-funded MIT researchers seek to meet this challenge with a new type of fertilizer, and call for more interdisciplinary research to optimize harvests.|
Nitrogen, phosphorous, and potassium are the three elements that support the productivity of all plants used for agriculture, and are the constituents of commercial fertilizers that farmers use throughout the world.
Potassium (also referred to as potash) is largely produced in the Northern Hemisphere, where it is abundant. In fact, the potash market is dominated by just a few producers, largely in Canada, Russia, and Belarus. As a result, potash (and fertilizers in general) can be accessed relatively affordably by farmers in northern regions, where it also happens to be a closer match for the soil nutrient needs of their farms and crops.
But that's not necessarily the case for farmers elsewhere. For tropical growing regions in Brazil and some countries in Africa, differing soil and rock compositions make for a poor match for the fertilizers that are currently on the market. When these fertilizers — which are resource intensive to produce — need to be shipped long distances to reach consumers in Southern Hemisphere countries, costs can skyrocket. When the fertilizer isn’t the right match for the soil needs, farmers may need to add more in order to achieve as much gain as their counterparts in the north, if they are even able to afford more in the first place.
So while these fertilizers promise higher yields, small- and medium-scale farmers still can end up with lower profits, higher soil salinity, a rapid reduction in overall soil fertility, and increased leaching into groundwater, rivers, and streams. This makes it challenging for these farmers to thrive, especially in Africa. Expensive or unsuitable fertilizer lowers food production capacity, affecting farmers’ economic and nutritional self-sufficiency. Now, at a time when the United Nations projects that global population will rise by to 8.5 billion in 2030 — an overall increase of over 1.2 billion people — the need for local, sustainable fertilizer solutions to increase yields is even more urgent.
Meeting food security needs with more interdisciplinary research
This mismatch — and the regional food security implications that it entails — was the inspiration for Antoine Allanore, associate professor of metallurgy in the Department of Materials Science and Engineering at MIT, to focus his efforts on finding alternative fertilizer materials. Over the last six years, he has built a research team, including Davide Ciceri, a research scientist in his lab through 2018.
Having immersed themselves in fertilizers research, Allanore and Ciceri have found the lack of attention by others in the materials science field to this topic surprising.
“Industry hasn’t put as much thought as is needed into doing research on the raw materials [used in fertilizers],” says Ciceri. “Their product has worked so far, and no one has complained, so there is little space for innovation.”
Allanore thinks of it this way: “Unfortunately, farming is not a very profitable field. They make so little compared to those who work in trade or food processing and marketing, which, as a result, have received a lot of investment and attention. Because of this lack of research investment, we know very little about what happens to some of the elements that we’re putting in the soil.”
This lack of investment is especially problematic for farmers in the Global South who are without affordable access to the fertilizers that are currently available on the market. Motivated by their desire to find local, sustainable fertilizer solutions for African farmers and fueled by J-WAFS seed funding, Allanore, Ciceri, and other members of their research team have created a road map that materials scientists and others can use to develop a new generation of potash-independent fertilizers suitable for African soils. Published last August in the journal Science of the Total Environment, the paper, “Local fertilizers to achieve food self-sufficiency in Africa,” was one the first comprehensive studies of the use of fertilizer across Africa from a materials science perspective. It indicated urgently needed advancements in fertilizer research, technology, and policy, and recommended approaches that can help to achieve the yield gains necessary to meet current and future demand sustainably.
“From the standpoint of materials processing, there’s really so much to do on the mineral resources required for fertilizers,” says Ciceri. “What we wanted to do was to promote a discussion in the community about this. Why is there no research on new fertilizer developments? What strategies are implementable? Is there enough field crop testing that can be done to support what chemists can do in the lab?”
While their paper was geared toward materials scientists, Allanore recognizes that what is needed is an interdisciplinary approach. “We are about to know the full genome of humans, but we don’t yet know how a crop uptakes nutrients,” he says. Collaboration between agronomists, soil scientists, materials scientists, economists, and others can improve our understanding of all of the interactions, materials, and products that go into obtaining the optimal yield of agricultural crops with minimal negative impact on the surrounding ecosystem. He is quick to state, however, that the goal is not to replicate what has been done with modern agriculture, but go beyond it to find sustainable solutions so that the African continent can provide its own food, profitability, and a decent life for the people who are growing crops.
Finding new sources for potassium and testing results
Professor Allanore’s lab has already discovered a potash alternative that is derived from potassium feldspar, a rock that is commonly found all over the world. To Ciceri, finding a solution in feldspar was startlingly obvious.
“Looking back at years of research, I was surprised to find that no one had looked to K-feldspar as a source,” he says. “It’s so abundant. How could it be that in 2015 our research team was the first to get potassium out of it?”
And yet, that’s just what they’ve been able to do. With the support of a partnership with two Brazilian entities, Terrativa and EMBRAPA (the Brazilian Agricultural Research Corporation), the research team was able to develop a hydrothermal process to turn K-feldspar rocks into a new fertilizing material. But while this early collaboration helped the researchers develop an understanding of feldspar and how it could be used as a fertilizer for specific crops in Brazil, the team did not have direct control or access to the agronomic trials.
That's where J-WAFS funding proved supportive. The 2017 seed grant provided the research team the opportunity to conduct an independent assessment of the fertilizing potential of the new materials, and also contextualize their discovery within a broader conversation about global food security, as they did in their paper.
For crop testing, they began with tomatoes, which are one of the most common and economically important horticultural crops, and ranked among the most consumed vegetables in the world. A collaboration with Allen Barker, a professor of plant and soil sciences at the Stockbridge School of Agriculture at the University of Massachusetts Amherst, made it possible. Barker provided greenhouse space for testing, as well as essential expertise in agronomy that helped the MIT research team perform the rigorous analysis of the new material that has, now, determined its effectiveness.
“This was an extremely important step for our research,” Allanore says. “The J-WAFS funding gave us the freedom to enter into this collaboration with the University of Massachusetts at Amherst. And, unlike what happens with corporate sponsorship research agreements, in this case we all had open access to the data.”
Allanore is particularly grateful to the contributions of Barker and his team, since the tests would not have been possible without their participation. The results of this work were published on Jan. 22, 2019, in the article “Fertilizing properties of potassium feldspar altered hydrothermally” in the journal Communications in Soil Science and Plant Analysis. The paper was co-authored by Ciceri, Barker, Allanore, and Thomas Close, another member of the MIT team currently completing his doctorate.
– Andi Sutton | Abdul Latif Jameel World Water and Food Systems Lab
MIT News Office | February 12, 2019
|Lucia Brunel uses an active microrheology, optical tweezer setup in the MIT Bioinstrumentation Lab during her 2017 Summer Scholar internship at MIT under Professors Gareth McKinley and Katharina Ribbeck. Photo, Denis Paiste, MIT MRL.|
2017 Summer Scholar Lucia Brunel is one of 43 outstanding American undergraduate students selected as Marshall Scholars for up to three years of study at leading British universities in a wide variety of disciplines beginning in September 2018.
During summer 2017, Brunel interned at MIT, where she worked on a joint project under Professors Gareth McKinley and Katharina Ribbeck. “My research project as a Summer Scholar was an investigation of the self-healing behavior of certain biological gels. This project was a great opportunity for me to participate in interdisciplinary materials science research with both mechanical and biological engineering components,” Brunel says.
"The whole lab was so excited to hear the great news,” says MIT graduate student Caroline Wagner, who supervised Brunel’s internship. “I had such a good time working with Lucia through the Summer Scholars program, and I wish her all the best in her future studies."
Brunel plans to study materials science at Cambridge University after she graduates from Northwestern University in June 2018 with both B.S. and M.S. degrees in Chemical and Biological Engineering. Brunel plans to work in the laboratory of Cambridge Centre for Medical Materials Co-Directors and Professors Ruth Cameron and Serena Best, whose research aims to improve performance of biopolymer scaffolds for tissue engineering. “My work in particular will focus on chemically modifying collagen-based scaffolds to achieve more selective and controllable cell affinity that can be tailored for the type of tissue that must be regenerated,” Brunel explains. Brunel previously received a Goldwater Scholarship, which supports students in science, mathematics, and engineering.
“My materials science research experience at MIT taught me many of the material characterization skills that I will utilize at the University of Cambridge,” says Brunel, who intends to pursue a PhD in the U.S. in the area of biomaterials after her Marshall Scholar program. Three MIT seniors also were named 2018 Marshall Scholars.
The Materials Research Laboratory sponsors the Summer Research Internship Program through the NSF REU program. Brunel participated through the former Materials Processing Center and Center for Materials Science and Engineering, which merged in October 2017 to form the Materials Research Laboratory at MIT.
The Summer Scholars program started in 1983, and has brought hundreds of the best science and engineering undergraduates in the country to MIT for graduate-level materials research. A wide range of project areas is available. Applications for summer 2018 must be submitted by Feb. 16, 2018.
Annual MIT Materials Day Symposium highlights latest innovations on Oct. 9, 2019.
Machine learning tools are both helping to design new materials and devices and to help those devices run at their best.
Optical spectrometers, for example, are devices that record Iight intensity as a function of wavelength and identify chemicals based on their response to light. MIT Associate Professor of Materials Science and Engineering Juejun (JJ) Hu, last year developed a new chip-based spectrometer that employs an algorithm which improves resolution 100 percent compared to the textbook limits, called Rayleigh limits.
“We developed an algorithm that allows us to extract the information with much better signal-to-noise ratio,” Hu explains. “We have validated the algorithm for many different kinds of spectrum.”
Unlike the conventional shape of glass lenses which are often curved, his new optical devices feature an array of specially designed optical antennas that add a phase delay to the incoming light, which enables many different functions. Hu currently is working with UMass researchers to perfect an algorithm that can screen potential designs for these devices. The algorithm can evaluate the workability of irregular shapes that go beyond conventional shapes likes circles and rectangles.
“The algorithm allows us to train it with existing data,” Hu says. “It can recognize the underlying connections between complex geometries and the electromagnetic response.” The algorithm can find hidden relations much faster than conventional full-scale simulation methods. The algorithm can also screen out potential combinations of materials and functions that just won’t work. “If you use conventional methods, you have to waste lots of time to exhaust all the possible design space and then come to this conclusion, but now our algorithm can tell you really quickly,” he says.
Hu will present his research at the MIT Materials Research Laboratory’s annual Materials Day Symposium on Wednesday, Oct. 9, in Kresge Auditorium. The Symposium runs from 8 a.m. to 3:30 p.m. and is immediately followed by a Poster Session in La Sala de Puerto Rico on the second floor of Stratton Student Center. Register here.
Atlantic Richfield Associate Professor of Energy Studies Elsa A. Olivetti will discuss her work on an artificial-intelligence system that scours through scientific papers to deduce materials science “recipes.” Her team is currently working on experimental verification, particularly focused on catalysts materials.
“We are constantly refining and improving our system from improving overall accuracy to expanding to other parts of the paper, such as results, to other kinds of documents, such as patents,” Olivetti says.
AI can also help to improve sustainability. “If we can know better how to make new materials, we might be able to inform how to make them in a lower resource consuming way,” Olivetti says.
Keynote speaker Dr. Brian Storey, Toyota Research Institute’s Director of Accelerated Materials Design & Discovery, will discuss several collaborative projects focusing on research and development of materials for battery and fuel cell electric vehicles.
Other Materials Day speakers are: Professor Carl V. Thompson, Director, Materials Research Laboratory; Professor Klavs F. Jensen, Departments of Chemical Engineering and Materials Science & Engineering; Professor Asu Ozdaglar, Department Head, Electrical Engineering & Computer Science; Professor Ju Li, Departments of Nuclear Science & Engineering and Materials Science & Engineering; and Assistant Professor Rafael Gomez-Bombarelli, Department of Materials Science & Engineering.
MIT graduate students and postdocs will give two-minute talks on their research during a “Poster Previews” session before the lunch break. The Poster Session runs 3:35 to 5:45 p.m. with an awards presentation at 5:30 p.m.
MIT’s vice president for research identifies three areas that show particular promise for climate action.
|While superior battery technology is still in our future, MIT Vice President for Research Maria Zuber is already encouraged by the increased use of renewable energy.|
Climate change is a very personal issue to Maria Zuber, MIT’s vice president for research. A native of eastern Pennsylvania, she watched her grandfathers, both coal miners, battle black-lung disease. “The burning of anthracite coal drove my community and was a central part of my childhood,” says Zuber. “Yet it’s been known since the 1800s that combustion of fossil fuels puts CO2 into the atmosphere, and that the effects can be damaging.”
Today, the catastrophic effects of climate change are showing up even faster than models predicted, she observes. “If you just look at it that way, it’s easy to despair.”
Yet Zuber, also the E. A. Griswold Professor of Geophysics, remains optimistic. “People are looking at those effects based on what we know now, but I think about the actions that will be taken when we have technological breakthroughs and an improved understanding of the climate system,” she explains. “Those breakthroughs will happen — we just don’t know exactly when.”
Zuber identifies three areas of MIT-based research that show particular promise for climate action: battery technology, renewable energy, and fusion.
“Batteries are key to combating climate change because in the deployment of renewable energy, one of the greatest challenges is intermittency,” she explains. “We need to store the power of wind and sun so we can use them when the sun isn’t shining and the wind isn’t blowing. We need better battery capacity, efficiency, and design, and we need batteries that are made out of common-earth materials as opposed to rare ones.”
At the third in a series of climate action-focused symposia sponsored by the Institute this academic year, Yet-Ming Chiang ’80, ScD ’85, the Kyocera Professor of Ceramics in MIT’s Department of Materials Science and Engineering, provided examples of this effort. Chiang is a cofounder of Form Energy, one of the portfolio companies of The Engine, an MIT-based innovation hub for startups focused on technology with potential for changing the world. Chiang described research and development of batteries based on materials such as sulfur and zinc, which are cheaper and more abundant than the lithium commonly used today.
Solar and wind
While superior battery technology is still in our future, Zuber is already encouraged by the increased use of renewable energy. “Solar and wind energy are really penetrating into society, and a lot of new jobs are being created as a result,” she says. “Just renewables won’t solve all the problems, though. We also have to move toward decarbonizing other parts of the energy system where we haven’t made as much progress. But you can really see the tide starting to turn.”
Zuber cites the work of Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology and founding faculty director of MIT.nano, who works to create next-generation, lightweight, flexible photovoltaics that could dramatically improve solar energy systems. “We have a lot going on in solar energy,” she says.
On the topic of fusion, Zuber’s enthusiasm is boundless. “Fusion is the process that powers the sun, and we need to bring that process down to Earth,” she explains. “The fuel is hydrogen, a component of water, so it’s practically free and virtually inexhaustible.” The greatest obstacle to working with fusion is designing a device that creates more energy than it uses for power. “This is a really difficult challenge,” she admits. “But fusion could be an important contributor to limiting the change in our climate. It doesn’t put CO2 in the atmosphere, and there’s no radioactive fuel waste involved.”
Zuber highlights the Institute’s collaboration with Commonwealth Fusion Systems (CFS), a startup spun out of MIT’s Plasma Science and Fusion Center. MIT’s role in CFS was conceived by researchers led by center director Dennis Whyte, the Hitachi America Professor of Engineering and cofounder of CFS.
“People never took fusion seriously, but they seem to be taking it seriously now,” says Zuber. “We have considerable investment in CFS. The fact that the private sector is also investing heavily in fusion energy indicates optimism that the technology has matured to the point where it’s a reasonable longer-term investment.”
In addition to research, Zuber described the Institute’s successful collaboration with other organizations and governments. In one example, MIT joined forces with two local organizations, Boston Medical Center and the Post Office Square Redevelopment Corporation, in a 2016 power-purchase agreement that resulted in the construction of a 650-acre, 60-megawatt solar farm on the site of a former tobacco farm in North Carolina. The power generated by the solar farm replaces power previously supplied by a coal-fired plant.
“We have also convened investment firms, fossil fuel companies, climate-scenario producers, environmental advocates, and NGOs, along with academics like ourselves, to explore the role of corporate disclosures with regard to climate change,” she says. “Companies are taking major risks if they don’t consider the financial consequences of global warming.”
Continued engagement with outside organizations and populations is key. “Climate change affects everybody on Earth, and MIT can’t solve a global problem alone,” Zuber points out. “A solution that might work here in Cambridge might not work in India or Africa, so we’ve sought out partners from different areas of the developing world. We need to consider those perspectives in energy solutions.”
Hope for the planet
Much of Zuber’s hope for climate action, she says, comes from MIT students.
“The greatest thing about our students is that they believe they can solve this problem,” she says. “We are not dispirited — we will keep working to find a solution.”
– MIT Resource Development | MIT News Office
April 22, 2020
Materials Day is the capstone event for MRL. The symposium and poster session are usually held in October. Speakers from industry as well as MIT professors present their latest research.
Member-only content is available to the MRL Advisory Board and Industry Collegium Members. To access the premium content simply log in. Premium content includes symposium presentations, presenter video, poster session abstracts and poster presentations.
Members please login to access all of the Materials Day content.
|MIT Materials Day Poster Session winners are [left to right] graduate students Vera Schroeder, Rachel C. Kurchin, Gerald J. Wang and Philipp Simons, and Postdoctoral Associate Mikhail Y. Shalaginov. Sixty students and postdocs presented their posters in La Sala de Puerto on Wednesday, Oct. 10, 2018. Of those, 20 gave two-minute poster previews during the Materials Day Symposium immediately before the Poster Session. Photo, Denis Paiste, MIT Materials Research Laboratory.|