Tuesday, 13 February 2018 16:46

Michael Concepcioñ

Summer Scholar Michael Concepción Santana works in the Cima Lab on hydrogels that can indicate changes in pH.

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Summer Scholar Michael Concepción Santana synthesized hydrogels that can indicate changes in pH near a patient’s tumor in an MRI scan. Photo, Denis Paiste, Materials Processing Center.

Cancer has long been known to make its immediate environment more acidic and starve it of oxygen [hypoxia], making measurements of these changes clinically important. “The amount of radiation you want to use to kill that tumor depends on how hypoxic the tumor is, and typically we don’t know how hypoxic it is,” says Michael J. Cima, David H. Koch Professor of Engineering at MIT.

MPC-CMSE Summer Scholar Michael Concepción Santana worked in the Cima Lab in the Koch Institute for Integrative Cancer Research at MIT, on a project to develop hydrogels that can serve as internal sensors, readable with an MRI, of a patient’s pH levels at a tumor site. Hydrogels are polymers that absorb large amounts of water.

This connection between cancer and the lack of oxygen was proposed in the 1920s by the German doctor, Otto H. Warburg, who won the Nobel Prize in Medicine in 1931. Cima’s lab has been working for several years to develop MRI contrast agents made from hydrogels. The Cima lab also is developing silicone-based contrast agents that can be implanted at the site of a tumor to measure changes in oxygen concentration through an MRI. Cima lab last year reported an implantable wireless sensor that monitors pH and dissolved oxygen.

Magnetic effect

“MRI is the machine health care professionals use to look into our bodies and look for pathologies and different diseases, so it’s a non-invasive test, and my project is working with MRI-readable pH sensors,” Concepción Santana explains. “At first, I synthesize the polymers and then I put the polymers in different pH environments.” He then analyzes their ability to show changes in pH levels with a specialized nuclear magnetic resonance (NMR) machine. Operating the Bruker minispec NMR is a new skill he learned this summer.

For Concepción Santana, the two-month project was an opportunity to delve into biomedical engineering, the field of research he’d like to pursue in graduate school. The rising senior at Polytechnic University, San Juan, Puerto Rico, is majoring in biomedical engineering as an undergrad. “I have synthesis experience, but this is my first time synthesizing polymers; so I’m really excited about doing research right here at the Cima Lab,” says Concepción Santana, who worked under supervision of materials science and engineering graduate student Gregory Ekchian [MEng, ’10].

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Summer Scholar Michael Concepción Santana used the Bruker minispec mq20 NMR analyzer in the Cima Lab at MIT to analyze the potential for different hydrogels to serve as internal sensors, readable with an MRI, of a patient’s pH levels at a tumor site. Photo, Denis Paiste, Materials Processing Center

Measuring relaxation

Specifically, he measured what are known as T1 and T2 relaxation modes of the hydrogels with NMR. This relates to their ability to display changes in an MRI machine. “MRI (H1) depends on the excitation and relaxation of protons. The difference in the rate at which the protons relax can provide contrast in images between different types of tissue and tissue and injected materials,” Ekchian explains.

“pH is an important indicator of tissue health and pH de-regulation is associated with several pathologies including cancer,” Concepción Santana explains. “That’s why we are using the polymer for pH sensing and using MRI to identify changes of pH that indicate cancer or different diseases.” If this work is successful, such pH sensors could help doctors determine tumor progression and treatment response.

Concepción Santana acknowledged the intensity of the Summer Scholars program at MIT. “Because in two weeks I have to do two months work, so I’ve been running around getting up here like 8 o’clock and getting off at 6, 7; so it’s been tough,” he says. “For the past few years I have been trying to do research with MRI agent contrast. So this is my first time doing synthesis and helping to improve that type of research for MRI agent contrast. The research accomplishments I have obtained at the Cima lab include contributing to my scientific knowledge, career plans, lab skills (polymer synthesis, Bruker Minispec and swelling ratios calculations) and my improvement toward research independence. In other words, working with Gregory Ekchian at the Cima lab strengthened my interest to apply to graduate school, and it expanded the knowledge I have gained through my professional development. “

‪MPC‬‬‬‬‬‪‬‬‬‬‬‬‬‬‬‬‬‬ and ‪CMSE‬‬‬‬‬‬ sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from ‪NSF‬‬‬‬‬‬’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program ran from June 7 through Aug. 6, 2016.‬‬‬‬‬ ‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬ 

 

– Denis Paiste, Materials Processing Center | Aug. 22, 2016

Tuesday, 13 February 2018 16:44

Ashley Del Valle Morales

Summer Scholar Ashley Del Valle Morales probes new silicon carbide system in MIT Microphotonics Center.
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Materials Science and Engineering graduate student Peter Su shows Summer Scholar Ashley Del Valle Morales how to operate a laser and detector system she will use during her summer project under Senior Research Scientist Dr. Anuradha Agarwal. The system combines an optical set up with a laser to drive light through an optical fiber into a sensor sample and collect light passed through resonators on the sample that help determine its quality as a sensor of target gas or liquid chemicals. Photo, Denis Paiste, Materials Processing Center

Lasers operating at the infrared wavelength of 1550 nanometers power high-speed fiber-optic Internet communications. MIT Microphotonics Center Principal Research Scientist Dr. Anuradha Agarwal  is developing chemical sensors based on the 1550 nanometer telecommunications wavelength using a new materials system built of silicon carbide on silicon dioxide on silicon.

MPC-CMSE Summer Scholar Ashley Del Valle Morales is working under Materials Science and Engineering graduate student Peter Su as part of a team in Agarwal’s lab to characterize this new system. Once the devices are fabricated, Del Valle Morales will use a laser system to determine how effectively the sensors detect the chemical N-methylaniline, a toxic industrial chemical.

Del Valle Morales, a rising junior at University of Puerto Rico, Mayaguez campus, also will test the silicon carbide based sensor before and after it is exposed to gamma rays. Tests will show whether detection capabilities or properties of the device change as a result of radiation exposure.

During the three-day selection process, in which this year’s group of 11 Summer Scholars heard presentations by faculty, postdocs and graduate students and also toured their labs, Del Valle says she was drawn to the Agarwal lab. “Because I have done research before, I know it’s really important to select a project you like and you’re interested in. Furthermore, a research in which you can expand your knowledge, so that was one point that helped me decide to join.

“I also liked the enthusiasm and the interest that the grad students and the principal research scientist showed. I think that’s very important. It makes me feel very welcome in the lab, and it makes me feel like I wouldn’t be alone in this whole process of learning something new,” Del Valle says.

“Having an MPC-CMSE Summer scholar working alongside a graduate student in our research program is an excellent opportunity for both the summer scholar and for our group,” Agarwal says. “Our graduate student learns how to be a good role model and mentor to the Summer Scholar who is typically just a few years younger, shares a passion for science and technology, and perhaps shares dreams and aspirations for a career in the field of engineering.”

“This year, the enthusiasm of our 2016 summer scholar, Ashley Del Valle Morales, is palpable and contagious. We are excited as she starts her research in microphotonic sensors,” Agarwal adds. “Research in our group progresses faster with the presence of a Summer Scholar, since we have a willing and able “scientist-in-training” in our midst. In fact, a 2009 MPC-CMSE Summer Scholar [Brian Albert], who came to us while still an undergrad at Columbia, graduated with a PhD in DMSE in 2016.”

Del Valle says she applied to the MPC-CMSE internship program in the spring knowing it was highly competitive because of the broad topics and choice of individual projects offered. “I started working on my essays and the whole application right away. I spent maybe three weeks writing and editing my essay with the help of my English professor,” she says.

MPC‬‬‬‬‬‪ and CMSE sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from NSF’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬

– Denis Paiste, Materials Processing Center
June 29, 2016

 

Tuesday, 13 February 2018 16:39

Erica Eggleton

Summer Scholar Erica Eggleton joins Van Vliet Lab to make and test lithium manganese oxide electrodes.
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Graduate student Frank McGrogan, left, is supervising the work of Summer Scholar Erica Eggleton on LMO electrodes for lithium ion batteries in the Van Vliet Lab. Photo, Denis Paiste, Materials Processing Center.

After studying fuel cells at Montana State University, Erica Eggleton knew she wanted to do some type of research this summer, either with a college or in industry. “I’ve always been really interested in renewable energy, and in my lab at Montana State, I study PEM [proton exchange membrane] fuel cells, so I wanted to stay in that realm of research,” she says.

Her quest brought Eggleton, who just finished her junior year, to MIT as a 2016 MPC-CMSE Summer Scholar, where she is working in the Van Vliet Lab on lithium manganese oxide [LMO] electrodes for lithium ion batteries. Materials science and engineering graduate student Frank McGrogan is supervising her work.

This year’s 11 Summer Scholars spent their first three days in the internship program hearing project pitches from faculty, postdocs and graduate students and touring their labs. “I definitely wanted to expand my knowledge on electrochemical-based processes and there were a couple of projects that were in that field. Then I looked more at the principal investigators [PIs] and talked to the grad students during the lab tours and this one definitely seemed like a good fit, community-wise. Also, I thought it would be beneficial for me to learn about the topic from more of a materials science standpoint, because I’m starting to question, if I want to go more into materials science in grad school or whether I’m actually more interested in chemical-based processes like now,” Eggleton says.

Lab head Krystyn Van Vliet, who holds MIT faculty appointments in both biological engineering and materials science and engineering, says, “From my perspective, REU [Research Experience for Undergraduates] students such as Erica bring great enthusiasm to our lab during the Summer Scholar research period. They provide a valuable mentoring opportunity to our graduate students who realize anew the excitement and potential of their challenging, multi-year research projects, and the REUs themselves contribute unique perspectives on how to solve lab challenges.

“I have had several REU students contribute so much to a project in the two months they were here that they were co-authors on publications, and the impressive career trajectories of those REUs who worked in my lab – ranging from young faculty to medical school to graduate engineering research – shows that they made the most of the REU opportunity at MIT,” Van Vliet adds.

Eggleton is studying the type of fatigue that makes lithium ion batteries less efficient over time. “We’re studying whether this is based off of certain stresses, cracking or fractures and how that’s affecting the overall efficiency of the battery. I know I’m going to be working on making different types of electrodes and then I will look at them using SEM [scanning electron microscopy] to analyze the film properties,” Eggleton says.

Working with McGrogan, Eggleton did indentation hardness testing and cracking tests in one of her first days on the job as an intern. She’ll be making electrodes and studying the materials with analytical techniques such as SEM.

McGrogan, in his first summer working with an undergraduate, says, “Working with my REU (Erica) has refreshed my perspective on my research, as she brings a new curiosity to the problems I'm trying to solve. Erica has met my research questions with eyes wide open, and I find her ambition and enthusiasm to be personally motivating. I feel certain that she will be an important contributor to my research projects by the end of the summer.”

MPC‬‬‬‬‬‪ and CMSE sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from NSF’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬

Denis Paiste, Materials Processing Center
June 29, 2016

 

 

Tuesday, 13 February 2018 16:37

Suna Njie

Summer Scholar Suna Njie works with new technique in Strano Lab.
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Suna Njie is working this summer in the Strano Lab on graphene fibers under postdoctoral associate Pingwei Liu. Two days into her project, Njie grew graphene and put it into an etching solution. Here, she removes salt contaminant from the graphene film by soaking it in water. The next step will be to scroll the graphene into fiber, a new technique developed by Liu. Photo, Denis Paiste, Materials Processing Center

Coming from a biology pre-med program at Alabama State University, junior Suna Njie wanted to try something new in her internship at MIT as an MPC-CMSE Summer Scholar. Her project on making graphene fibers in the Strano Lab is giving her just that opportunity.

“I chose this lab because it was different from what I have done before, however it is not too out of my comfort zone. This internship is about material science and engineering. I have never done anything in materials science, but here, I will be working with graphene to create fibers out that could possibly have biological implications. I could definitely use this in my future endeavors,” Njie says.

Njie hopes to pursue a joint M.D./PhD program after graduation. “When I enter an M.D./PhD program, I could use graphene in a project to further some technology in biology also, so it’s the best of both worlds,” she says.

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Close up of graphene film soaking in water to remove contaminants prior to scrolling the graphene into fiber. Photo, Denis Paiste, Materials Processing Center

Working under postdoctoral associate Pingwei Liu, Njie is fabricating polymer/graphene composite films and will scroll it into fiber, using a technique that Liu developed, which is is in the process of publication. In this project, Njie will do more mechanical tests to study the detailed elongation and failure mechanism of these new fibers, and check the stiffness and toughness of the fiber and the effect of the graphene.

“I grew graphene with a chemical vapor deposition method yesterday, and I put it into the etching solution, and now I’m trying to rinse the film in clean water,” Njie explains, during one of her first days working in the lab. “...So, right now I’m just waiting, leaving it in water, and repeating the rinse, so we can get as much of the salt contaminant out, and then I’m going to scroll it into fiber, and then I’ll have fiber.”

Michael S. Strano, Carbon P. Dubbs Professor of Chemical Engineering, says of the summer internship program, “The MPC-CMSE scholars are an extremely impressive, carefully selected set of students who have performed marvelously in my lab over the years. Although only with us for eight weeks, these students very often end up publishing with us, and always bring new ideas and energy to our projects.”

MPC‬‬‬‬‪ and CMSE sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from NSF’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬‬

– Denis Paiste, Materials Processing Center
June 29, 2016

 

Tuesday, 13 February 2018 16:35

Michael Porter

Summer Scholar Michael Porter interns with Hammond Lab to develop targeted drug delivery.
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MIT biological engineering graduate student Brett Geiger, left, and MPC-CMSE Summer Scholar Michael Porter hold a model of knee joints in Hammond Lab, which is working to develop a nanoparticle-based drug delivery system for osteoarthritis in the knee. Photo, Denis Paiste, Materials Processing Center

Osteoarthritis, a progressive deterioration of the cartilage in the joints, affects about 27 million Americans, with nearly 550,000 a year getting knee replacement surgery, according to a National Institutes of Health Fact Sheet. Researchers in the Hammond Lab at MIT are working on a nanoparticle-based drug delivery technique to slow the progress of knee cartilage wearing out.

MPC-CMSE Summer Scholar Michael Porter gravitated to the lab of Paula Hammond, head of the chemical engineering department at MIT, following his interest in drug delivery and imaging. “I wanted to look for some opportunity that would kind of nurture that interest and that’s how I found this program here at MIT,” Porter, a junior chemical engineering major at Johns Hopkins University.

“As I started taking more elective classes, I found myself gravitating more toward materials applications,” Porter says. “I was interested in drug delivery and Hammond Lab does a lot of the biomaterials, particularly, polymers and such.”

Porter will be working on the knee joint project under MIT biological engineering graduate student Brett Geiger. Porter will synthesize layer-by-layer nanoparticles designed to penetrate and stay in cartilage, using cartilage from cow’s knees as a test material.

“Part of the challenge is to get those design criteria within a nanoparticle,” Porter says. “We’re going to see how, once I’ve built the nanoparticles, how well they penetrate, and not only penetrate, but how long do they stay there to release the drug application.”

MPC‬‬‬‬‬‪ and CMSE sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from NSF’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬

– Denis Paiste, Materials Processing Center
June 29, 2016

 

Tuesday, 13 February 2018 15:26

Jennifer Coulter

Summer Scholar Jennifer Coulter models how spinning colloidal particles move through a fixed array of obstacles.

 

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MPC_CMSE Summer Scholar Jennifer Coulter worked on modeling the behavior of ferromagnetic particles stimulated by a rotating magnetic field to spin in a passive cluster of non-magnetic particles. Image on computer in background shows map of the path traveled by individual active particles as they spin through the passive matrix, with colors denoting particle location at different times. Purple represents the particles’ positions at the start of the simulation, while red represents the particles’ positions at the end. Coulter interned under Alfredo Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering at MIT. Photo, Denis Paiste, Materials Processing Center.

Earlier this year, MIT Associate Professor Alfredo Alexander-Katz’s group demonstrated experimentally that ferromagnetic particles spinning under a rotating magnetic field in a milky suspension are attracted to each other across relatively long distances in a crowd of non-magnetic particles.

MPC-CMSE Summer Scholar Jennifer Coulter interned with Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering at MIT, this summer on a project to develop a more generalized computer model for these active spinning particles in a passive colloidal mixture. “We’re studying the interactions of the spinners with the passive particles through simulation,” Coulter says. Describing this theoretical environment, Coulter explains, “Only the spinners move.” The non-magnetic particles are now fixed in a pattern without moving during the simulation.

This project fits into the Alexander-Katz lab’s work on a wide range of active soft matter challenges from understanding how neurotransmitters move from one neuron to another in the brain to how single-celled organisms sense each other at a distance. “The power of soft means [that] with very small stimuli we can actually have large or strong changes,” Alexander-Katz said during a presentation to Summer Scholars in June. Alexander-Katz is part of the Physics of Living Systems group.

For Coulter, a rising senior at Rutgers University whose prior work focused on high-energy physics, biophysics is new territory. “The way I’ve been working with him on this project has been an experience in using what I know in terms of computing and general physics knowledge to develop and explore a new system,” she says.

“I’ve actually found that a lot of the work I did in high-energy physics has been really useful because that’s also computational, even though it’s very different. So I had some skills coming in, but I’ve definitely had some time to work on them here,” Coulter says.

“I’m running larger scale things, where I have to deal with huge numbers and lots of data, so I need to consider things in Unix command lines,” she says. “I’m using different computers to run my code, because I can’t run it on my laptop. It would overheat or take days,” Coulter explains. She is writing much of the code for this project herself from scratch using Python and a mix of Unix tools including Bash and Shell scripts.

“I think that in terms of just general computing stuff, in Unix and other things, it’s been really good to spend more time working on that, because those are skills I hope to use in grad school. I’d like to go for computational physics, probably,” Coulter says.

Using this computer model, Coulter analyzed how changes in simulation specifications affect the end result. For example, she could alter the speed at which the magnetic field rotates, change the torque from hydrodynamic interactions and modify the attractive or repulsive force between spinners and passive particles.

MIT researchers led by Alfredo Alexander-Katz, the Walter Henry Gale Associate Professor of Materials Science and Engineering at MIT, found long-range interaction between particles in a liquid medium based entirely on their motions. Video, Melanie Gonick, MIT.

“The key thing that we’re going to vary is a parameter that’s going to help us describe the disorder of the way we’ve arranged the passive particles; so we want to study how disorder affects the transport of the spinners through the passive particles,” Coulter says. The simulations cover a range from a highly ordered system through a range of different distortions to the ordered system to see how spinners behave as disorder increases.

She hopes to learn under what conditions spinners move in a straight line versus a diffuse pattern, that is, scatter in different directions. “I think it would be cool if we could see really diffusive transport in relation to adding disorder to our system,” Coulter says. “The end goal is to compare the active matter system to a system that’s currently very popular in terms of topological materials and 2D materials and transport in those materials. So we would like to try to create this system as an analogue to that more difficult to study system.”

Coulter says Alexander-Katz has been an extremely involved advisor. “I think in terms of my personal growth, actually the best part of my experience here has been just working with Prof. Alexander-Katz,” she says. “It’s really nice to be able to talk to him for an hour or more at a time, several times a week. He’s really supported me and gives really good feedback, and I think in terms of my development as a scientist, a lot of what I’ve gained from this has just been in my experience working with him. I really appreciate his role as a mentor.”

Success for her project would be characterizing the disorder of the arrangement of passive particles, and how it changes the nature of transport for the spinners, Coulter suggests. “It’s actually, I think, something we’re pretty close to attaining, but since it was a smaller project, we are now starting to do some more final runs of the code. I’m about to get some of the last results soon ... so hopefully they’re the good kind. They’ve looked really promising up to this point.” 

‪MPC‬‬‬‬‬‪‬‬‬‬‬‬‬‬‬‬‬‬ and ‪CMSE‬‬‬‬‬‬ sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from ‪NSF‬‬‬‬‬‬’s Materials Research Science and Engineering Centers program (grant number DMR-1419807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬ ‬‬‬‬

 

Denis Paiste, Materials Processing Center | Aug. 22, 2016

Tuesday, 13 February 2018 15:22

Victoria Yao

Summer Scholar Victoria Yao experiments with water-based, flow-driven battery concept in Brushett Lab.

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MPC-CMSE Summer Scholar Victoria Yao shows a mixture of sodium thiosulfate being stirred in a solution of copper hexacyanoferrate where its reacts to produce larger compounds that can be filtered out of the solution. These compounds are being developed for use in electrodes for a water-based flow-driven battery for grid level storage. Photo, Maria E. Aglietti, Materials Processing Center.

A convection oven cooks more uniformly because a fan creates a steady flow of hot air around the food being cooked. MIT’s St. Laurent Career Development Professor of Chemical Engineering, Fikile R. Brushett, is applying that principle to a new water-based battery design that pumps a steady flow of charge-carrying ions through a battery to create a more uniform distribution of ions in the cell.

“We’re fabricating an aqueous [water-based] battery which is safe, cheap and scalable,” MPC-CMSE Summer Scholar Victoria Yao explains. A rising junior at Vanderbilt University, Yao is majoring in chemical engineering. This summer, she worked with graduate student Thomas J. Carney to develop a convection cell battery, in which electrolyte would flow through the electrode material, rather than remain static as in a conventional battery.

During her summer internship in the Brushett Research Group, Yao synthesized electrode materials in the same chemical family as Prussian blue, which is commonly used to dye fabric and to color makeup such as eye shadow. Prussian blue is the common name for ferric ferrocyanide, but unlike some highly poisonous cyanide compounds, Prussian blue is considered non-toxic and is even ingested to treat radiation poisoning.

Yao created the Prussian blue-like materials in a liquid solution of metal nitrates, adding potassium hexacyanoferrate to precipitate the desired compounds, such as copper hexacyanoferrate. Sodium thiosulfate is added to make the particles bigger and change the amount of energy stored in the material. She then separated out the particles with a filter or centrifuge. Once dried, the colorful particles were mixed with additives to make “inks” that can be precisely dripped on carbon paper to form thin electrodes for battery testing. “Immediately after you make the ink, you need to pipette it onto carbon paper, let it dry, and then remove any contaminants under vacuum,” Yao says.

These thin electrode cells were tested in a flow-through reactor – an arrangement of glass components in an “H” configuration – that runs for hours at a time, sometimes overnight, to gather sufficient data to measure their capacity and efficiency. The carbon-paper electrodes are placed in the upright glass tubes with a sodium chloride [table salt] solution connecting the two through the middle. After adding a reference electrode, Yao bubbled argon gas through the experimental setup.

“I’ve made eight different powders, and tested their energy storage properties with thin electrodes,” she says.

After making and testing thin electrodes, Yao plans to move to producing thick porous electrodes, which could yield higher energy density. These thick electrodes require more raw material, which is compressed into pellets.

In presenting this project, which he calls Convection Enhanced Electrochemical Energy Storage, to Summer Scholars in June, Brushett said, “We’ve got a proof of concept, and we’re really excited. ... Ideally we’d like to translate this proof-of-concept device into a little canister-like flow cell with thick porous electrodes and pump electrolyte through the reactor... and there we should have our convection battery.”

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MPC-CMSE Summer Scholar Victoria Yao holds a container with a thin electrode made of carbon with a copper hexacyanoferrate [Prussian blue] type active area at the top end. Photo, Maria E. Aglietti, Materials Processing Center

“Prussian blue-related chemical compounds have an open framework that allows ions to move in and out of the two battery electrodes while remaining solvated (bound to water molecules) by the electrolyte solution which, in turn, enables fast reactions. When coupled with a flowing electrolyte we may be able to develop energy dense batteries with thick electrodes and tunable power output,” Brushett says. The project fits into the Brushett lab’s larger goal of helping to build a sustainable energy economy through innovative, new energy storage technologies.

“Victoria has been instrumental in synthesizing and characterizing Prussian blue analogue materials for use in convection-based energy storage devices this summer. The MPC-CMSE Summer Scholar’s program provides opportunities for talented undergraduates from across the country to work on cutting-edge research projects here at MIT,” Brushett says. “Not only do these students learn of the discipline, tenacity, and creativity required to perform fundamental research but our graduate students learn how to mentor enthusiastic but less experienced lab workers. Her dedication and aptitude have directly accelerated our research! We are very happy to have hosted her this summer.”

‪MPC‬‬‬‬‬‪‬‬‬‬‬‬‬‬‬‬‬‬ and ‪CMSE‬‬‬‬‬‬ sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from ‪NSF‬‬‬‬‬‬’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬ ‬‬‬‬ 

 

Denis Paiste, Materials Processing Center | Aug. 22, 2016

 Related: Going with the Flow Battery

Tuesday, 13 February 2018 15:19

Grant Smith

Summer Scholar Grant Smith works to establish parameters for making ferromagnetic thin films in Luqiao Liu lab.

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MPC-CMSE Summer Scholar Grant Smith looks into a sputter deposition chamber where he makes ultra thin films [from 2 to 10 nanometers thick] of special magnetic materials suitable for spin-based electronics. He is working under MIT Assistant Professor of Electrical Engineering and Computer Science Luqiao Liu. Smith’s summer project involves growing the films, making experimental device prototypes and measuring their properties. Spin-based systems such as magnetic tunnel junctions are often used in computer memory systems. Photo, Denis Paiste, Materials Processing Center.

MPC-CMSE Summer Scholar Grant Smith is working in the lab of MIT Assistant Professor of Electrical Engineering and Computer Science Luqiao Liu, to create special thin film materials suitable for spin-based devices such as magnetic tunnel junctions used in computer memory.

Smith is operating a sputter deposition chamber where he grows these ultra thin films from 2 to 10 nanometers thick. His summer project involves making devices that are precursors to a memory device and measuring their properties.

Magnetic tunnel junctions used in spin-based systems for computer memory got their start with a key breakthrough in 1994 at MIT by Dr. Jagadeesh S. Moodera and colleagues. They are especially valued because they retain information even when the power is off.

A magnetic tunnel junction pairs two thin film materials, each with a special property called ferromagnetism. “Those ferromagnetic layers can either have their magnetizations aligned or anti-aligned,” Smith explains. If they are aligned, that is their magnetic fields both point in the same direction, the electrons in one layer will have more states available for them in the other layer, but if they are anti-aligned [with magnetic fields pointing in opposite directions], there will be fewer states for electrons available in that other layer.

Change in resistance

“When you’re trying to push a current through and the magnetizations are aligned, the resistance is much lower. So if you fix one of the magnetic layers and flip the other one based on whether you want it to be a zero or a one or if you’re just trying to detect the existence of a magnetic field, you’ll be able to see something on the order of a 100 to 300 percent change in the resistance of that device,” Smith says. This is about 10 to 30 times greater that the approximately 10 percent shift in resistance in the first such devices.

Smith is working with a dual-layer of an antiferromagnet called iridium manganese and a ferromagnet called cobalt iron boron. “Those two in conjunction, when you condition them in a specific way, they pin the magnetization of the one ferromagnet in that one specific direction. So that is your fixed layer,” he explains.

For his summer project, Smith seeks to establish that ability to grow these magnetic tunnel junctions in Liu’s lab, and if that is a success, to try to manipulate that magnetization with the spin texture of a topological semimetal in order to do switching.

Nice spot to be

“I’m just happy to learn anything about this field basically,” says Smith, a rising senior at Penn State majoring in physics, who hopes to pursue a doctorate in the sciences. “I’m glad to be learning how to manufacture these magnetic tunnel junctions. That’s a really important skill. They’re used everywhere as far as doing experiments in this field. They’re useful in industry. It’s actually a very nice spot to be in.”

Liu, who joined the MIT faculty in September 2015, says, “So far I have been very glad with summer intern Grant Smith’s performance. Having a summer intern working in our lab does provide a good advantage to our research as it allows us to look into directions that we were not able to previously due to a shortage of manpower. Moreover, Mr. Smith is really diligent and smart. It is a very nice experience so far to work with such a motivated undergraduate student.”

Change of pace

For Smith, working in Liu’s lab on materials at room temperature is a change of pace from his work at Penn State on materials at extremely low temperatures in the range of 4 kelvin [minus 452.47 F]. “When you’re working with these sort of things you can learn about new behaviors, new scientific phenomenon,” he says. “Here everything is very room temperature focused working much closer towards, working much more closely with the place industry is at right now,” Smith says.

MPC‬‬‬‬‬‬‬‪ and CMSE sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from NSF’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807). The program runs from June 7 through Aug. 6, 2016. ‬‬‬‬‬‬‬

 

Denis Paiste, Materials Processing Center | July 27, 2016

Tuesday, 13 February 2018 15:16

Justin Cheng

Summer Scholar Justin Cheng explores process in Berggren group for making ordered metal nanostructures that display interesting new properties.

Summer Scholar Justin Cheng 6 MEA Web
Summer Scholar Justin Cheng holds an experimental sample of nanostructured gold on silicon that has potential for use in sensors and display technologies based on the selective light absorption properties of the material that arise from plasmonic excitations on the surface of the gold. Photo, Maria E. Aglietti.

Ordered patterns of gold nanoparticles on a silicon base can be stimulated to produce collective electron waves known as plasmons that absorb only certain narrow bands of light making them promising for a wide array of sensors and display technologies in medicine, industry and science.

MPC-CMSE Summer Scholar Justin Cheng worked this summer in Professor of Electrical Engineering Karl K. Berggren’s Quantum Nanostructures and Nanofabrication Group to develop specialized techniques for forming these patterns in gold on silicon. “Ideally, we’d want to be able to get arrays of gold nanoparticles to be completely ordered,” Cheng says.

“My work deals with the fundamentals of how to write a pattern using electron-beam lithography, how to deposit the gold, and how to heat up the substrate so we can get completely regular arrays of particles,” Cheng explains.

Cheng wrote code to produce a pattern that will guide the dewetting of a thin gold film into nanoparticles, examined partially ordered grids with an electron microscope, and worked in a clean room to spin-coat polymer resist onto samples, develop the resist, and plasma clean samples. He is part of a team that includes graduate student Sarah Goodman, postdoctoral associate Mostafa Bedewy, and he was assisted by Research Specialist James Daley, who is the lab manager in MIT’s NanoStructures Laboratory, where this work was performed.

“Plasmons are collective oscillations of the free-electron density at the surface of a material, and they give metal nanostructures amazing properties that are very useful in applications like sensing, optics and various devices,” Goodman explained in a presentation to Summer Scholars in June. “Plasmonic arrays are very good for visible displays, for example, because their color can be tuned based on size and geometry.”

This multi-step fabrication process begins with spin coating hydrogen silsesquioxane [HSQ], which is a special electron-beam resist, or mask, onto a silicon substrate. Cheng worked on software used to write a pattern onto the resist through electron-beam lithography. Unlike some resists, HSQ becomes more chemically resistant as you expose it to electron beams, he says. The entire substrate is about 1 cm by 1 cm (0.39 inch x 0.39 inch), he notes, and the write area is about 100 microns (0.0039 inch) wide.

After the electron-beam lithography step, the resist is put through an aqueous [water-based] developer solution of sodium hydroxide and sodium chloride, which leaves behind an ordered array of posts on top of the silicon layer. “When we put the sample in the developer solution, all of the less chemically resistant areas of the HSQ mask come off, and only the posts remain,” Cheng says. Then, Daley deposits a gold layer on top of the posts with physical vapor deposition. Next, the sample is heat treated until the gold layer decomposes into droplets that self-assemble into nanoparticles guided by the posts.

Solid-state dewetting

A key underlying materials science phenomenon at work in this self-assembly, Cheng says, is known as solid-state dewetting. “Self-assembly is a process where you apply certain conditions to a material that allow it to undergo a transformation over a large area. So it’s a very efficient patterning technique,” Goodman explains.

Summer Scholar Justin Cheng 3 MEA Web
Summer Scholar Justin Cheng inserts a sample into a scanning electron microscope in the NanoStructures Laboratory. Cheng explored processes for making ordered metal nanostructures that display interesting new properties. Photo, Maria E. Aglietti.

Because of repulsive interaction between the silicon and gold layers, the gold tends to form droplets, which can be coaxed into patterns around the posts. The Berggren group is working collaboratively with Carl V. Thompson, the Stavros Salapatas Professor of Materials Science and Engineering, who is an expert in solid-state dewetting. Thompson also is director of the Materials Processing Center.Using a scanning electron microscope, Cheng examines these patterns to determine their quality and consistency. “The gold naturally forms droplets because there is a driving force for it to decrease the surface area it shares with the silicon. It doesn’t look completely ordered but you can see beginnings of some order in the dewetting,” he says while showing an SEM image on a computer. “[In] other pictures you can clearly see the beginnings of patterning.”

“When we take the posts and we make them closer together, you can see that the gold likes to dewet into somewhat regular patterns. These aren’t completely regular in all cases, but for certain post sizes and spacings, we start to see regular arrays.
Our goal is to successfully fabricate a plasmonic array of ordered, monodisperse [equally sized] gold nanoparticles,” Cheng explains.

Goodman notes that the group of Carl V. Thompson, the Stavros Salapatas Professor of Materials Science and Engineering at MIT, has demonstrated exquisite control over dewetting in single crystalline films at the micron scale, but the Berggren group hopes to extend this control down to the nanoscale. “This will be a really key result if we’re able to bring this dewetting that’s beautifully controlled on the micro scale and enable that on the nanoscale,” Goodman says.

Cheng, a rising senior at Rutgers University, says that during his summer internship in Berggren’s lab, he learned to operate the scanning electron microscope and learned about nanofabrication processes. “I have learned a lot. Aside from the lab work that I’m doing, I’ve been scripting for the [LayoutEditor] CAD program that I use, and I’ve been using Matlab, too,” he says. “I actually learned a lot about image analysis because there are a lot of steps that go into image analysis. Since we have so much data and so many images to analyze, I’m doing it quantitatively and automatically to make sure I have repeatability.” 

‪MPC‬‬‬‬‬‪‬‬‬‬‬‬‬‬‬‬‬‬ and ‪CMSE‬‬‬‬‬‬ sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from ‪NSF‬‬‬‬‬‬’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program ran from June 7 through Aug. 6, 2016.‬‬‬‬‬ ‬‬‬‬

 

‬‬‬‬‬‬‬‬‬‬– Denis Paiste, Materials Processing Center | Aug. 22, 2016

 

Tuesday, 13 February 2018 15:11

Ashley Kaiser

Summer Scholar Ashley Kaiser delves into hybrid carbon nanotube materials research in nectslab.

Ashley Kaiser 6 MEA Web
Ashley Kaiser holds samples of carbon nanotubes she grew in the Wardle lab as part of her summer project studying carbon nanotube-based aligned nanofiber carbon matrix nanocomposites [CNT A-CMNCs]. The carbon nanotubes are on the left, and the pyrolytic carbon is on the right. These new materials have potential aerospace applications. Photo, Maria E. Aglietti.

University of Massachusetts Amherst chemical engineering major Ashley Kaiser joined MIT Professor of Aeronautics and Astronautics Brian L. Wardle's necstlab this summer with past experience in growing graphene and examining it with Raman spectroscopy.

During her new summer internship, Kaiser, who is a rising senior, is learning new fabrication and characterization techniques to further necstlab’s research on carbon nanotube aligned nanofiber carbon matrix nanocomposites [CNT A-CMNCs].

High temperature composites

MPC-CMSE Summer Scholar Kaiser is making these composites, which are treated at high temperatures from 600 to 1400 Celsius [1112 F to 2552 F], and analyzing their composition to study the confinement effects of the carbon nanotubes in the carbon matrix. Similar heat-treated material, called pyrolytic carbon [PyC], is currently used for aerospace applications but in a simpler form without embedded carbon nanotubes. “It’s super hard and lightweight, and since carbon nanotubes are also very strong and lightweight as well, we would like to introduce these nanotubes inside this existing matrix,” Kaiser explains.

“Ashley’s primary contribution is to help us understand how the aligned carbon nanotubes facilitate the self-organization and meso-scale evolution of the graphitic crystallites that comprise the pyrolytic carbons, and how control over the processing (i.e., pyrolysis) temperature can modify the structure and morphology of A-CNT-PyC hybrid nanocomposite materials on the nanoscale,” necstlab Postdoctoral Associate Itai Stein says.

“The results from Ashley’s project will be invaluable to better understanding the process-structure-property relations of these high temperature materials,” Stein adds. Kaiser’s project builds on work done in necstlab by 2015 MPC-CMSE Summer Intern Alexander Constable, who studied the structural evolution of pyrolytic carbon (PyC) as a function of processing parameters and the effects of aligned carbon nanotube (A-CNT) confinement.

Four key steps

Her project consists of four steps, Kaiser explains:

• Carbon nanotube growth
• Polymer resin infusion
• Oven curing the polymer matrix nanocomposites
• High temperature heat treatment (pyrolysis)

“Basically, we want to fabricate and characterize the composites to see what effect the carbon nanotubes are having on the final structure to address several questions – what it looks like, if the nanotubes stay aligned, are there functional groups inside of that, are there defects, what’s the crystallite size, etc.” Kaiser says.

“We are seeing that when we are putting our nanotubes into our composite, the effect of them governs the meso-scale [submicron scale], which means that the way the atoms are arranging in our crystallites isn’t changing too much just from having our nanotubes there, which is interesting. So in terms of scaling this up to, say, something in industry, the fact that it’s not changing the entire atomic scale is beneficial because it means that processing may not be too different,” she says.

“This composite is a closely-related material with similar strength to PyC because the atoms are arranged similarly, but it’s more lightweight, at least we think, which is a step up in improving the current technology,” she adds.

Adding new skills

Although she previously grew graphene using chemical vapor deposition, growing the carbon nanotubes using a similar chemical vapor deposition process at MIT and making the final nanocomposites requires more steps. “After the CNT growth, I do polymer infusion under vacuum, then the samples are cured in an oven, and then they are pyrolyzed in an even larger furnace. In this way, I’m working on many different pieces of equipment in the lab, which is great experimental experience,” Kaiser says.

Ashley Kaiser 3 MEA Web
Ashley Kaiser prepares to grow carbon nanotubes [CNTs] on a silicon wafer with a coating of alumina and iron in a 1-inch furnace. Alumina and iron act as catalysts to stimulate the CNTs to grow. During her summer project in the Wardle lab, Kaiser grew pyrolytic carbon as a control in addition to growing carbon nanotubes, turning out 5 samples of each at a time. Photo, Maria E. Aglietti.

Although she has previous experience with Raman spectroscopy at UMass and from her 2015 summer internship at 3M, she is learning new characterization skills at MIT this summer, including SEM [scanning electron microscopy], FTIR [Fourier Transform Infrared Spectroscopy], XRD [X-ray Diffraction] and SAXS [Small Angle X-ray Scattering]. “I think that’s going to be really beneficial experience moving forward into graduate work,” she suggests.

Diamond-like structure

“The overarching goal is to study the impact of carbon nanotube confinement on the graphitic crystallites that comprise the pyrolytic carbon, or the matrix of our nanocomposites,” Kaiser explains. “We are finding that as our temperature is increasing, our material is evolving, and it’s forming essentially a lower density pyrolytic carbon which may be more diamond-like, and very strong. We are interested in examining how the nanotubes are affecting the carbon matrix crystallite growth in the composite at various processing temperatures. If this material can be processed to maintain high strength while becoming even lighter, it could be an ideal candidate for aerospace applications.

“I’m essentially doing all the processing, characterization and analysis on my own, so I’m really very solo on this project. I have about 50 robust samples to fabricate and analyze over the course of my summer internship here at MIT,” Kaiser explains. “I’m definitely quite busy with that, but I’m very excited about it at the same time.”

MPC‬‬‬‬‬‪‬‬‬‬ and ‪CMSE‬‬‬ sponsor the nine-week National Science Foundation Research Experience for Undergraduates (NSF REU) internships with support from ‪NSF‬‬‬’s Materials Research Science and Engineering Centers program (grant number DMR-14-19807).‬ The program runs from June 7 through Aug. 6, 2016.‬‬‬‬‬ ‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬

 

Denis Paiste, Materials Processing Center | July 27, 2016

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